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Part 3/RAIL TRANSIT CAPACITY - Transportation Research Board

1. 3 87 Part 3 RAIL TRANSIT CAPACITY Page 3 ii Contents Transit Capacity and Quality of Service Manual 11 EXAMPLE PROBLEMS cccsssssssssssssesssssssersesessersesessersesessersesessessesessessesessens 3 89 APPENDIX A EXHIBITS IN U S CUSTOMARY UNITS eene 3 101 LIST OF EXHIBITS Exhibit 3 1 Line Capacity Flowchart eese 3 5 Exhibit 3 2 Average Rail Transit Headway Components in Seconds 3 6 Exhibit 3 3 Train Capacity Flow Chart sees eene 3 7 Exhibit 3 4 Distance Time Plot of Two Consecutive Trains acceleration and braking curves omitted for Clarity sposini nese an ave hee erre 3 13 Exhibit 3 5 Station Headway for Lines at Capacity sse 3 14 Exhibit 3 6 Speed Limits on Curves and Switches sesseee 3 14 Exhibit 3 7 Distance Speed Chart sess eene 3 15 Exhibit 3 8 Effect of Grade on Station Headway sss 3 15 Exhibit 3 9 Headway Changes with Voltage sese 3 16 Exhibit 3 10 Moving Block Headways with 45 Second Dwell and 20 Second Operating Margin Compared with Conventional Fixed Block Systems 3 17 Exhibit 3 11 Terminal Station Track Layout esee 3 18 Exhibit 3 12 Flat Junction Track Layout sese 3 20 Exhibit 3 13 Headway Result Summary in Seconds with 2
2. 180 m 600 ft 150 m 500 ft 120m 400ft 90m 300 ft 60 m 200 ft Train Length LIGHT RAIL Capacity passengers hour track NOTE Assumes peak hour average passenger loading of 0 5 m p Capacity for one track of a grade separated rail transit line Total of operating margin and dwell time ranges from 55 seconds lower bound to 70 seconds upper bound 13 The lower ranges for the short cars in Vancouver and Chicago should not be used in the simple procedure method which is based on 6 to 8 car trains of 23 meter 75 foot long cars Linear train loading Peak hour factor Part 3 RAIL TRANSIT CAPACITY Page 3 51 Chapter 6 Grade Separated Systems Capacity Transit Capacity and Quality of Service Manual Weakest link Constraints at the maximum load point station Exhibit 3 42 Achievable Capacity With Moving Block Signaling System 54 000 50 000 46 000 42 000 38 000 34 000 30 000 26 000 22 000 Capacity passengers hour track 18 000 14 000 10 000 180 m 600 ft 150m 500ft 120m 400ft 90m 300ft 60 m 200 ft Train Length NOTE Assumes peak hour average passenger loading of 0 5 m p Capacity for one track of a grade separated rail transit line Total of operating margin and dwell time ranges from 55 seconds lower bound to 70 seconds upper bound Note that with the exception
3. 3 50 Exhibit 3 41 Achievable Capacity with Multiple Command Cab Control Signaling SYSTEM M Em 3 51 Exhibit 3 42 Achievable Capacity With Moving Block Signaling System 3 52 Exhibit 3 43 Minimum Train Separation Parameters sss 3 54 Exhibit 3 44 Minimum Train Separation versus Length esee 3 55 Exhibit 3 45 Distance Speed Braking Into a Station esses 3 56 Exhibit 3 46 1995 Peak Period Station Dwell Times for Heavily Used Systems seconds penne esas 3 58 Exhibit 3 47 Passengers per Unit Train Length Major North American Rail Trunks 15 Minute Peak erat tee e ERE ER ET EEE EO chier 3 60 Exhibit 3 48 Diversity of Peak Hour and Peak 15 Minute Loading 3 61 Exhibit 3 49 Typical Maximum Passenger Capacities of Grade Separated Rail Transit Excluding All Seated Commuter Rail esee 3 62 Exhibit 3 50 Data Values for Single Track LRT Travel Time 3 65 Exhibit 3 51 Light Rail Travel Time Over Single Track Section 3 65 Exhibit 3 52 Light Rail Platform Options at a Crossing ssseeeeeeee 3 68 Exhibit 3 53 Light Rail Single Track Terminus with Separate Unloading Platform Baltimore ce 3 eno EE T E 3 70 Exhibit 3 54 Wheelchair Access Examples sseeeeeeeeen
4. Part 3 RAIL TRANSIT CAPACITY Page 3 22 Chapter 2 Train Control and Signaling Transit Capacity and Quality of Service Manual 3 STATION DWELL TIMES INTRODUCTION Station dwell times are the major component of headways at close frequencies as shown in Exhibit 3 14 based on a heavy rail system at capacity operating 180 meter long trains with a cab control signaling system The best achievable headways under these circumstances are in the range of 110 to 125 seconds Controlling station dwell time is the combination of dwell time and a reasonable operating margin the dwell time during a normal peak hour that controls the minimum regular headway Controlling dwell takes into account routine perturbations in operations but not major or irregular disruptions The sum of controlling dwell and the train control system s minimum train separation time produces the maximum train throughput without headway interference In this chapter the components of dwell time will be examined and procedures provided to determine dwell times Dwell Time Components Dwell time is comprised of the time passenger flow occurs a further time before the doors are closed and then a time while waiting to depart with the doors closed Exhibit 3 15 shows these dwell components for the peak period of four selected rail transit stations Each of the rail transit systems serving the particular stations has a different operating philosophy BART in the San Francis
5. Upper Limit Operational of Mean SD margin s System amp City Mean SD samples One SD Two SD 15 20 BART San Francisco 46 3 12 0 290 583 70 2 613 663 CTS Calgary 35 7 15 7 91 51 5 67 0 50 7 55 7 ETS Edmonton 24 7 8 8 18 33 6 42 3 39 7 44 7 NYCT New York 307 20 9 380 516 726 45 77 507 PATH New Jersey 513 23 0 252 643 973 663 71 3 Tri Met Portland 32 0 19 4 118 51 4 70 8 47 0 52 0 MTS San Diego 51 1 17 9 34 69 1 86 8 66 1 71 1 Muni San Francisco 50 4 21 8 75 72 2 93 9 654 70 4 TTC Toronto 36 6 23 2 322 598 83 0 51 6 56 6 SkyTrain Vancouver 30 7 7 2 82 37 9 45 1 457 50 7 SD standard deviation The third method is often the most practical involving selection of dwell times and operational allowances from comparable existing systems Chapter 5 Operating Issues discusses the need for and approaches to estimating a reasonable operating margin and provides additional examples of existing controlling dwells Part 3 RAIL TRANSIT CAPACITY Page 3 28 Chapter 3 Station Dwell Times Transit Capacity and Quality of Service Manual 4 PASSENGER LOADING LEVELS INTRODUCTION Establishing the loading level of rail transit is the final step in determining capacity After the maximum train throughput has been calculated from the inverse of the sum of signaling separa
6. TTC Toronto ETS Edmonton CTS Calgary Muni San Francisco BART San Francisco MTS San Diego Tri Met Portland Muni San Francisco NYCT IRT New York PATH New York NYCT IND New York SkyTrain Vancouver Muni San Francisco Part 3 RAIL TRANSIT CAPACITY Steps 3 57 Steps 0 1 2 3 4 3 97 Steps lighting arding 4 21 Steps Steps 5 21 5 6 Time per passenger per single stream s NOTE Level boarding except up or down steps where indicated Page 3 25 Flow time is the time in seconds for a single entering or exiting passenger to cross the threshold of the rail transit car doorway per single stream of doorway width Extensive rail transit door flow rate data collection took place in 1995 for the TCRP Project A 8 Rail Transit Capacity Data were collected from a representative set of high use systems and categorized by the type of entry level entry being the most common then light rail with door stairwells with and without fare collection at the entrance The data sets were then partitioned into mainly boarding mainly alighting and mixed flows The results are summarized in Exhibit 3 16 Chapter 3 Station Dwell Times Transit Capacity and Quality of Service Manual Passengers ascend steps into a light rail vehicle faster street level than they exit The overall fastest flow rate 1 11 seconds per passenger per ed they descend them on single stream was ob
7. Chicago TA2D E F Eros 157 ie 2 0 Tri Rail Miami Bi Level III 1988 159 6 1 2 0 CalTrain San Francisco Gallery Coach 1985 87 148 5 7 1 9 SCRRA Los Angeles Bi Level V Mod 1992 93 148 5 7 1 9 Metra Chicago Gallery 1995 148 57 19 ___ Single level cars NICTD Chicago TMU 1 1992 130 5 0 1 6 NJT New Jersey Comet IIB Brass 126 Pe 1 6 Metro North New York M 6 D 1993 126 4 9 1 6 MBTA Boston CTC 1A 1989 90 122 4 7 1 55 NJT New Jersey Comet III 1990 91 118 4 6 1 5 LIRR New York M 3 1985 120 46 1 5 SEPTA Philadelphia JW2 C 1987 118 4 6 1 5 MARC Baltimore Coach 1992 3 120 46 1 5 MARC Baltimore Coach 1985 87 114 44 1 45 NJT New Jersey Comet II IA Eu 113 lee 1 45 LIRR New York M 3 1985 114 44 1 45 MARC Baltimore E H Cab 1991 114 4 4 1 45 VRE Washington DC Cab 1992 112 43 1 4 Metro North New York SPV 2000 1981 109 42 1 4 NICTD Chicago EMU 2 1992 110 42 1 4 Metro North New York M 6 B 1993 106 4 1 1 35 MARC Baltimore E H Cab 1985 87 104 40 1 3 NJT New Jersey Comet III 1990 91 103 40 1 3 MBTA Boston BTC 3 1987 88 96 37 1 2 AMT Montreal MR90 emu 1994 95 3 7 1 2 NICTD Chicago EMU 1 1982 93 36 1 2 NJT New Jersey Comet IIB 1987 88 88 3 4 1 1 Conn DOT New York SPV 2000 1979 84 32 1 05 Part 3 RAIL TRANSIT CAPACITY
8. Margins 5 idea e e tee e ibn e eH EE re eI e EORR Ec dein de 3 39 Estimating Margins eiecit ERR eee 3 43 Skip Stop Operation eere pte DOR RR I DRESS Rer pepererunt 3 43 Passenger Actuated DOOtS 4 s rete etie tp oet edere tiene 3 44 Other Station Constraints soiis eeceeecesecesecssecsseceecseecseeeseseaeesaeeeeeeeseseeeseenseenaes 3 44 Wheelchair Accommodations eese ener 3 45 6 GRADE SEPARATED SYSTEMS CAPACITY eerte eee ense tn sen tnnnn 3 47 InttOdUCtiOl i ec ei ee ie E E e Pete tice seus dederit ere e bet te eih 3 47 The Weakest Lank 245 sa ennui niet eh a ea ei ee bee iens 3 47 Growth and Achievable Capacity eese ener 3 48 Simple Procedure iecit tod Her ee eei 3 48 Complete Procedure et Ueber e ced lubes even oe E Rester ts 3 52 7 LIGHT RAIL CAPACITY eeeeeeeee eee eeee este rK IEEE statu sons tatu KESTE 3 63 Introductio nre ie e ee AL eee E iiec e eie to bn cest 3 63 Selecting the Weakest Link sese eene nenne nenne 3 63 Other Capacity Issues etti otn Der PR PERU ER ERO TRU RR i 3 63 Single Trac ce 3 64 Calculating Single Track Headway Restrictions essere 3 64 Signaled Sections 5e ree per gnaw agin annie 3 66 On street Operations vies ern eet eere epe here ee i rere beh 3 66 Determining On Street Capacity 0 cece cee cesecsecseecseeeeseeeeeeeeeseesseesecesecsaeesaeenaes 3 67 Right
9. North South HR 22 9 68 82 3 6 MARTA Atlanta East West P HR 22 9 68 77 3 4 HR heavy rail LR light rail CR commuter rail NOTE Service through NYCT s 53rd St Tunnel is provided by line E operating 18 35 m cars and line F operating 22 8 m cars Seats and car loadings are presented as E F The number of passengers per foot given is for the combined lines individually this value is 3 3 for the E and 3 0 for the F Step 6 Determining an Appropriate Peak Hour Factor The next step is to adjust the hourly capacity from the 15 minute rate within the peak hour to a peak hour rate using a peak hour factor from Chapter 4 Passenger Loading Levels The peak hour factor is calculated according to Equation 3 9 with a summary of results shown in Exhibit 3 48 The peak hour factor was also used in Method Four for calculating the station dwell time If this method was used then obviously the same peak hour factor must be used Otherwise the factor should be selected based on the rail mode and the type of system A summary table is reproduced below to assist Unless there is sufficient similarity with an existing operation to use that specific figure the recommended peak hour factors are e 0 80 for heavy rail e 0 75 for light rail and e 0 60 for commuter rail operated by electric multiple unit trains Page 3 60 Chapter 6 Grade Separated Systems Capacity Transit Capacity and Quality of Service Manual Exhibit 3 4
10. Train Length Exhibit 3 60 Suggested AGT Separation Calculation Default Values An alternative form of this Term Unit Description Heavy Rail AGT Description HeavwRail AGT table in U S customary units P m positioning error 6 25 6 25 appears n Appendix A L m length of the longest train 200 50 D m distance from front of train to exit block 10 0 K 926 service braking rate 75 75 B train detection uncertainty constant 2 4 4 fixed block B train detection uncertainty constant 1 1 moving block tos S time for overspeed governor to operate 3 1 tjl S time lost to braking jerk limitation 0 5 0 5 ds m s service acceleration rate 1 3 0 6 dg m s service deceleration rate 1 8 1 0 tbr S brake system reaction time 1 5 0 5 Vmax km h maximum line velocity 100 80 mbsd m moving block safety distance 50 25 The results show that separation times with a simulated single aspect block system are two to three times longer than with the more complex and expensive moving block signaling system The moving block results agree with those of Auer the only reference specializing in automated guideway transit train control Here typical short train AGT separation with moving block control was cited at 15 seconds The separation range is wide and highly dependent on the train control system of the proprietary AGT system The best method of determining the minimum train separation is from the sy
11. Transit Capacity and Quality of Service Manual Exhibit 3 50 Data Values for Single Track LRT Travel Time Term Value Jerk limitation time 0 5 seconds Brake system reaction time 1 5 seconds 1 Dwell time 15 25 seconds 1 Service braking rate 1 8 m s 4 3 ft s Speed margin 1 1 to 1 2 Operating margin time 10 30 seconds Exhibit 3 51 Light Rail Travel Time Over Single Track Section 350 300 250 O o 200 E E E z 150 E 100 No stations 50 1 station k amp 2 stations 0 200 400 600 800 1000 1200 1400 1600 1800 2000 2200 2400 Single Track Length m NOTE Assumes speed limit of 55 km h train length of 55 m 20 second dwell time and other data as per Exhibit 3 50 The recommended closest headway is twice this time plus an operating allowance The value of the maximum single track section speed should be the appropriate speed limit for that section A speed of 55 km h 35 mph is a suitable value for most protected grade separated lines If the single track section is on street then a speed below the traffic speed limit should be used If there are signalized intersections an allowance of half the signal cycle should be added to the travel time for each such intersection adjusted for any improvements possible from traffic signal pre emption Trains should be scheduled from their termi
12. tom m Equation 3 16 where Hmm minimum headway s T s minimum train separation s ta dwell time s Lom operating margin s Part 3 RAIL TRANSIT CAPACITY Page 3 61 Chapter 6 Grade Separated Systems Capacity Transit Capacity and Quality of Service Manual Lax train throughput per hour Cras maximum single track capacity in passengers per peak hour direction L train length m or ft P loading level in passengers per meter or foot of train length and PHF peak hour factor Given the range of values that can be calculated estimated or assigned for the components of Equation 3 16 it is appropriate that the results be expressed as a range The results should be checked for reasonableness against typical capacities in Exhibit 3 49 which is based on the simple procedure loading levels of 5 passengers per meter 1 5 passengers per foot for light rail and 6 passengers per meter 1 8 passengers per foot for heavy rail approximately 0 5 m 5 4 ft per passenger Higher levels are possible only if less comfortable loading levels have been used Lower levels would result from the assumption that all passengers are seated inclusion of an excessive operating margin or errors in the calculation This chart is not an appropriate check for electric multiple unit commuter rail whose signaling systems are usually designed for lower throughput with loading levels based on all seated passengers C
13. 13 These concur with field data and although a reliable guide are not a substitute for a full and careful simulation of the train control system in conjunction with a multiple train performance simulation Exhibit 3 13 Headway Result Summary in Seconds with 200 m 660 ft train The components of headway for a cab signaling system with typical heavy rail parameters are shown in Exhibit 3 14 with a station dwell of 45 seconds and an operating margin of 25 seconds The components are shown in the order of Equation 3 4 with terms running from the bottom upwards Dwell is the dominant component The next chapter deals with dwells while approaches to reduce dwell and thus increase capacity are addressed in Chapter 10 Exhibit 3 14 Headway Components for Cab Control Signaling with a 120 Second Headway The components of headway for the above mid range cab control data are shown in the headway Operating Margin 25 3 components note the importance of station dwell Station Dwell 41 7 Reaction Time 15 Jerk Limitation 0 5 EI Overspeed Allowance 3 4 Safe Separation Time 12 5 Time to Travel Own Length ee Time to Clear Platform 18 0 5 10 15 20 25 30 35 40 45 Time seconds Part 3 RAIL TRANSIT CAPACITY Page 3 21 Chapter 2 Train Control and Signaling Transit Capacity and Quality of Service Manual This page intentionally blank
14. 3 4 Distance Time Plot of Two Consecutive Trains acceleration and braking curves omitted for clarity dwell om sst Station Y Rear of Leading Train Minimum o Headw ay O c i Safe Separation Distance sst Safe Separation Time om Operating Margin Front of Following Train Station X uality of Service Manual The suggested 45 seconds dwell is higher than the 20 30 seconds often used in simulation programs Time 2 H s pe bs zs Ases u IE GEL f tty tt d Va K 2d 2v V max ME i Equation 3 4 where typical values shown in square brackets H s station headway s L length of the longest train 200 m or 660 feet D distance from front of stopped train to start of station exit block 70 m or 33 feet Va station approach speed m s V max maximum line speed m s K braking safety factor worst case service braking is K of specified normal rate typically 75 75 B 7 separation safety factor equivalent to number of braking distances plus a margin surrogate for blocks that separate trains see text bse time for overspeed governor to operate 3 s ti time lost to braking jerk limitation 0 5 s thy operator and brake system reaction time 7 5 s ta dwell time 45 s see also Chapter 2 Lom operating margin 20 s see also Chapter 4 d initial service acceleration rate 1 3 m s or 4 3 fus and d service deceleration
15. 79 6 64 125 1 6 lee Chicago State Subway HR 48 0 46 75 1 6 CalTrain San Fran CalTrain CR 85 0 146 117 1 4 eee bs York Jamaica Penn Sta CR 85 0 120 117 14 Metra Chicago Metra Electric CR 85 0 E gs 1 3 r i Atlanta pasan HR 75 0 LS IN 1 1 MARTA Atlanta East West HR 75 0 1 0 HR heavy rail LR light rail CR commuter rail NOTE Service through NYCT s 53rd St Tunnel is provided by line E operating 60 2 ft cars and line F operating 74 7 ft cars Seats and car loadings are presented as E F The number of passengers per foot given is for the combined lines individually this value is 3 3 for the E and 3 0 for the F Part 3 RAIL TRANSIT CAPACITY Page 3 104 Appendix A Exhibits in U S Customary Units Transit Capacity and Quality of Service Manual Exhibit 3 51a Light Rail Travel Time Over Single Track Section 350 300 250 O o 200 E g g 150 100 No stations 50 1 station k 2 stations 0 2000 4000 6000 8000 Single Track Length ft NOTE Assumes speed limit of 35 mph train length of 185 ft 20 second dwell time and other To estimate best headway multiply data as per Exhibit 3 50 The recommended closest headway is twice this time plus an single track time by two and add operating allowance an operating margin Exhibit 3 55a Recommended Loading Level Range for Light Rail Vehic
16. Capacity Basics Transit Capacity and Quality of Service Manual THE BASICS Many rail transit capacity calculations add constants multipliers reductive factors or other methods to correlate theory with practice In this manual emphasis has been placed on reducing the number of qualifications and quantifying describing and explaining adjustments between theory and practice in determining rail transit capacity This manual uses two definitions of capacity Design Capacity The maximum number of passengers past a single point in an hour in one direction on a single track Design capacity is similar to or the same as maximum capacity theoretical capacity or theoretical maximum capacity expressions used in other work It makes no allowance for whether those spaces going by each hour will be used they would be fully used only if passengers uniformly filled the trains throughout the peak hour This does not occur and a more practical definition is required Achievable capacity takes into account that demand fluctuates over the peak hour and that not all trains or all cars of a train are equally and uniformly full of passengers Achievable Capacity The maximum number of passengers that can be carried in an hour in one direction on a single track allowing for the diversity of demand Achievable capacity sometimes called practical capacity refers to capacity in one direction on a single track This is necessary as mos
17. Chapter 4 d E service deceleration rate 7 3 m s or 4 3 fus and Sub moving block safety distance 50 m or 165 feet Equation 3 6 determines the station headway for a moving block signaling system with a variable safety separation Part 3 RAIL TRANSIT CAPACITY Page 3 16 Chapter 2 Train Control and Signaling Transit Capacity and Quality of Service Manual 2 2 H s EXE 100 B Ya Gi GSOAG Ie jo t tty tt tf t K 2d 1 0 1G 2v v cate a max Equation 3 6 where P positioning error 6 25 m or 20 ft B separation safety factor equivalent to number of braking distances 1 0 G grade percentage into station and bs time for overspeed governor to operate s 5 s Equation 3 6 adjusts the safety separation entering a station due to any grade A downgrade will increase the braking distance and so require a longer safety separation and vice versa For simplification the acceleration due to gravity 9 807m s is rounded up to 10 0 m s 33 ft s The results of Equation 3 5 and Equation 3 6 are shown in Exhibit 3 10 The resultant minimum headway of 97 seconds occurs at an approach speed of 56 km h 35 mph The respective curves for a conventional three aspect signaling system and a cab control system are included for comparison As would be expected a moving block system with a speed variable safety distance shows the lowest overall headway The difference between the two methods of de
18. One variation uses sectioned power supply Power is disconnected for a given distance behind an operating train These operating variations are not fully accommodated in the methodology of Chapters 2 and 6 If the basic AGT performance criteria are known then the procedures of Chapter 6 will provide an approximation of the minimum train separation time for a range of AGT train controls from a moving block signaling system to a simple fixed block system A surrogate of this can be roughly simulated by setting the train detection uncertainty factor B at four times the minimum braking distance The results are shown in Exhibit 3 58 and Exhibit 3 59 for trains of typical AGT lengths and the specific AGT values in Exhibit 3 60 with terms adjusted from typical rail transit values shaded Exhibit 3 58 AGT Minimum Train Separation Times Train Length Fixed Block Moving Block 50m 160ft 48 7 seconds 16 7 seconds 25 m o ft 37 6 seconds 13 4 seconds 12 5 m 40 ft 20 5 seconds 11 2 seconds AGT has a relatively low share of transit ridership Part 3 RAIL TRANSIT CAPACITY Page 3 83 Chapter 9 Automated Guideway Transit Capacity Transit Capacity and Quality of Service Manual Exhibit 3 59 AGT Train Separation versus Length 60 E Moving Block O Fixed Block 50 B o i Train Separation s wo eo 20 4 10 4 0 50 m 160 ft 25 m 80 ft 12 5 m 40 ft
19. Page 3 81 Chapter 8 Commuter Rail Capacity Transit Capacity and Quality of Service Manual This page intentionally blank Part 3 RAIL TRANSIT CAPACITY Page 3 82 Chapter 8 Commuter Rail Capacity Transit Capacity and Quality of Service Manual 9 AUTOMATED GUIDEWAY TRANSIT CAPACITY INTRODUCTION Automated guideway transit AGT fits into the category of Grade Separated Rail whose capacity determination is specified in Chapter 6 However there are some nuances specific to AGT that must be considered AGT is an almost negligible part of urban public fixed guideway transit being used for less than 1 10th of one percent of passenger trips in the U S increasing only when institutional systems are considered most of which are intra airport shuttles Technology ranges widely from the standard gauge advanced light rapid transit downtown people movers in Detroit and Miami to small scale monorails in amusement parks All AGT systems are proprietary designs As such their performance acceleration braking rate balancing speed and vehicle size and capacity vary greatly TRAIN CONTROL SEPARATION Train control systems on automated guideway transit range from sophisticated moving block signaling systems to basic manual systems in which only one train may be on a section of line or the entire line at a time Manual or radio dispatching may ensure that a train does not leave a station until the leading train has left the station ahead
20. The almost generic Siemens D wag car used in nine systems with some dimensional changes has a range of 5 0 to 8 0 passengers per meter of car length 1 5 to 2 4 p ft of car length The lower level of 5 passengers per meter length 1 5 p ft length with a standing space per passenger of 0 4 m 4 3 ft corresponds closely with the recommended quality loading of an average of 0 5 m 5 4 ft per passenger Exhibit 3 24 Linear Passenger Loading Articulated LRVs Siemens Duwag 25 m ouem cette articulated E Baltimore 29 m large car Passengers Unit Length m Standing Space m2 p Train length as a surrogate for capacity An alternative figure using U S customary units appears in Appendix A Part 3 RAIL TRANSIT CAPACITY Page 3 33 Chapter 4 Passenger Loading Levels Transit Capacity and Quality of Service Manual An alternative figure using U S customary units appears in Appendix A An alternative table using U S customary units appears in Appendix A Applying Equation 3 9 to selected heavy rail cars produces loading levels in passengers per unit length shown in Exhibit 3 25 As would be expected the smaller and narrower cars in Vancouver and Chicago have lower loadings per unit length The more generic 75 ft 23 m long cars used in over twelve North American cities have a remarkably close data set for each of the three variations 4 and 3 door versions and transverse or lon
21. a m following a short gap in service The different loading train by train is significant and it is difficult to visually pick out the peak hour or the 15 minute peak period Exhibit 3 28 Individual A M Train Loads TTC Yonge Subway Wellesley Southbound Jan 11 1995 2000 1800 1600 1400 1200 1000 800 600 400 200 0 6 05 6 25 6 46 7 06 7 26 7 46 8 06 8 26 8 47 9 07 9 27 9 47 10 07 10 27 10 48 11 08 11 28 11 48 Passengers Time Exhibit 3 29 shows an a m peak period for BC Transit that although without major delays shows the irregular loading from train to train due to the interlace of short turn trains with regular service from 7 30 a m onwards Exhibit 3 29 Individual A M Train Loads Vancouver SkyTrain Broadway Station Inbound October 27 1994 50 trains 6 932 passengers in Data Set 400 S e eo o88B88g Passengers B e 6 51 6 57 7 08 7 09 7 14 7 20 7 26 7 32 7 37 7 43 7 49 7 55 8 00 8 06 8 12 8 18 8 24 8 29 8 35 8 41 8 47 8 52 8 58 Time The peak hour factors for many North American systems are tabulated in Exhibit 3 30 Diversity of loading within a car and among cars of a train are included in the peak Part 3 RAIL TRANSIT CAPACITY Page 3 36 Chapter 4 Passenger Loading Levels Transit Capacity and Quality of Servi
22. bahn have many or all of the characteristics of heavy rail transit operated by light rail equipment Part 3 RAIL TRANSIT CAPACITY Page 3 76 Chapter 7 Light Rail Capacity Transit Capacity and Quality of Service Manual 8 COMMUTER RAIL CAPACITY INTRODUCTION Commuter rail ridership in North America is dominated by the systems in the New York area where the busiest routes use electric multiple unit trains on dedicated tracks with little or no freight service The capacity of such systems can best be determined from the procedures of Chapter 6 Grade Separated Systems Capacity Care must be taken to take into account the sometimes lower vehicle performance and lower throughput of signaling systems where these are based on railroad rather than rapid transit practices Elsewhere with the exception of SEPTA s Philadelphia lines Chicago s Metra Electric and South Shore lines and the Mont Royal tunnel line of the AMT in Montr al commuter rail uses diesel locomotive hauled coaches and follows railroad practices Electric locomotive hauled coaches are also being used by SEPTA and New Jersey Transit on routes that also see electric multiple unit cars Dual powered electric and diesel locomotives are used by the Long Island Rail Road and Metro North Railroad in the New York area All new starts are likely to use diesel locomotive hauled coaches For most commuter rail lines the determination of capacity is at once both simple and approximate U
23. each car of a fully loaded train BC Transit has measured car loadings at a station where passengers are regularly passed up as shown in Exhibit 3 27 Exhibit 3 27 Peak Hour Passenger Distribution Between Cars of Trains Ed m 6 00 a m 12 00 p m B 7 00 9 00 a m 8 00 9 00 a m L17 30 8 30 a m er o a D Passenger Distribution Passenger Distribution ka P e p e iy 1 2 3 4 1 2 3 4 5 6 Number of Cars in Train Number of Cars in Train Vancouver SkyTrain Broadway Station Toronto Yonge Subway Wellesley Station NOTE 1 0represents even loading Vancouver data collected inbound direction Oct 27 1994 50 trains 6 932 passengers Toronto data collected southbound direction Jan 11 1995 99 trains 66 263 passengers In Vancouver there is no significant variation in the average loading diversity between the peak hour and the peak period both of which remain within the range of 5 to 6 The imbalance for cars on individual trains ranges from 61 to 33 The evenness of loading can be attributed to four factors the short trains wide platforms close headways and dispersed entrance exit locations between the stations of this automated driverless system Toronto s Yonge Street subway shows a more uneven
24. from disrupting terminal operations Junctions should not constrain capacity Part 3 RAIL TRANSIT CAPACITY Page 3 19 Chapter 2 Train Control and Signaling Transit Capacity and Quality of Service Manual Exhibit 3 12 Flat Junction Track Layout T i Cc gt A The worst case is based on a train lower left held at signal A while a train of length T moves from signal B to clear the interlocking at C The minimum operable headway is the line headway of train A plus the time required for the conflicting train to clear the interlocking plus the extra time for train A to brake to a stop and accelerate back to line speed Ignoring specific block locations and transition spirals this can be expressed approximately as H j H 1 ERI Q2 Lc a a d Equation 3 8 where typical values shown in square brackets H j limiting headway at junction s H l line headway 32 seconds T train length 200 meters or 655 feet S track separation 70 meters or 33 feet C switch angle factor 5 77 for 6 switch 6 41 for 8 switch and 9 62 for 10 switch as initial service acceleration rate 7 3 m s or 4 3 fus d service deceleration rate 1 3 m s or 4 3 fus vi line speed 100 km h 27 8 m s or 60 mph 91 ft s te switch throw and lock time 6 seconds and bii operating margin time s The limiting headway at the junction can then be calculated u
25. in U S Customary Units 1000 900 800 700 600 500 400 300 200 100 Stopping distance feet Transit Capacity and Quality of Service Manual Exhibit 3 45a Distance Speed Braking Into a Station Speed mph Exhibit 3 47a Passengers per Unit Train Length Major North American Trunks 15 Minute Peak Length Avg Pass System amp City Trunk Name Mode ft Seats _ Pass Car ft NYCTA New York 53rd Street Tunnel HR see note 50 70 197 227 3 2 Ivers New York Lexington Ave Local HR 51 0 44 144 2 8 NYCTA New York Steinway Tunnel HR 51 0 44 144 2 8 pesa New York Broadway Local HR 51 0 44 135 2 7 TTC Toronto Yonge Subway HR 74 5 80 197 2 7 cn New York Lexington Ave Ex HR 51 0 44 123 24 NYCTA New York Joralemon St Tun HR 51 0 44 122 2 4 eras New York Broadway Express HR 51 0 44 119 2 3 NYCTA New York Manhattan Bridge HR 74 7 74 162 2 2 lores New York Clark Street HR 51 0 44 102 2 0 CTS Calgary South Line LR 79 6 64 153 1 9 Ie Transit Toronto Lakeshore East CR 85 0 162 152 1 8 BCT Vancouver SkyTrain HR 40 7 36 73 1 8 PATH New York World Trade Center HR 51 0 31 92 1 8 PATH New York 33rd St HR 51 0 31 88 1 7 Ives fase Dearborn Subway HR 48 0 46 82 1 7 NYCTA New York 60th Street Tunnel HR 74 7 74 126 1 7 lors to New York Heres St Tunnel HR 74 7 74 123 1 6 CTS Calgary Northeast Line LR
26. loading between cars In the morning peak period the rear of the train is consistently more heavily loaded reflecting the dominance of the major transfer station at Bloor Street with the interchange at the northern end of the Yonge subway platform As would be expected there is less variation in the average car loading diversity between the peak hour and the peak period due to the pressures on passengers to spread along the platforms at busy times The average diversity of individual car loading over the peak period has a range of 26 to 39 The unbalance for cars on individual trains ranges from 156 to 89 Loading diversity within a car Loading diversity within a train Part 3 RAIL TRANSIT CAPACITY Page 3 35 Chapter 4 Passenger Loading Levels Transit Capacity and Quality of Service Manual Loading diversity over the It is this peak 15 minute period that provides the third and most important diversity peak period factor termed the peak hour factor and defined by Eus I PHF Equation 3 10 15 min where PHF Peak hour factor Ryu Ridership in peak hour and Rismin Ridership in peak 15 minutes Passengers do not arrive evenly and uniformly on any rail transit system as shown dramatically over the extended peak period in Exhibit 3 28 for the Toronto Transit Commission s Yonge subway This shows the realities of day to day rail transit operation The morning peak 15 minutes has a pronounced abnormality at 8 35
27. maintenance costs of multiple aspect color light signals although it is prudent and usual to leave signals at interlockings and occasionally on the final approach to and exit from each station Reducing the number of color light signals makes it economically feasible to increase the number of aspects and it is typical although not universal to have the equivalent of five aspects on a cab signaling system A typical selection of reference speeds would be 80 70 50 35 and 0 km h 50 43 31 22 and 0 mph MOVING BLOCK SIGNALING SYSTEMS Moving block signaling systems are also called transmission based or communication based signaling systems A moving block signaling system can be compared to a fixed block system with very small blocks and a large number of aspects However a moving block signaling system has neither blocks nor aspects The system is based on a continuous or frequent calculation of the clear safe distance ahead of each train and then relaying the appropriate speed braking or acceleration rate to each train This requires a continuous or frequent two way communication with each train and a precise knowledge of a train s location speed and length and fixed details of the line curves grades interlockings and stations Based on this information a computer can calculate the next stopping point of each train often referred to as the target point and command the train to brake accelerate or coast accordingly The
28. minimum separation are the two major factors in determining line capacity In many circumstances dwells are the dominant factor The third factor in headway is any operational allowance or margin In some cases this margin can be added to the dwell time to create a controlling dwell time An example of these headway components is shown in Exhibit 3 2 based on data from an at capacity line in New York Exhibit 3 2 Average Rail Transit Headway Components in Seconds 70 60 4 B o Time seconds wo o 20 4 10 4 Dwell Time Train Separation Operating Margin The three main components of dwell times are e passenger flow time e door open time after flow ceases and e waiting to depart time after doors close These components vary widely from system to system The methodology to determine dwell times is contained in Chapter 3 Station Dwell Times and their associated operating margins in Chapter 5 Operating Issues Commuter Rail Dwells Dwells on many commuter rail lines are set by schedule or policy and can be relatively independent of passenger flows although the schedule may be based on anticipated passenger flow times As a result passenger flow times on commuter rail can have a lesser effect on capacity than occurs on other modes Part 3 RAIL TRANSIT CAPACITY Page 3 6 Chapter 1 Rail Capacity Basics Transit Capacity and Quality of Service Manual TRAIN CAR CAPACITY Introduction Train capacity is th
29. minutes in a rush but five minutes is the minimum scheduled time Capacity into the station could be increased by improving track connections to the West Side Yard and so further reducing the number of trains which must be turned in Penn Station this change would permit the East River tunnels to be operated with three tracks in the peak direction and allow the operation of additional trains This modification would however only meet projected demand in the short term In the longer term new rail lines and new or expanded terminal facilities will be required Station Dwells Station dwell times on commuter rail lines are generally not as critical as they are on rapid transit and light rail lines as frequencies are lower and major stations have multiple platforms In most cases the longest dwells are at the downtown terminals where the train is not blocking others while passenger activity takes place Passenger flows are generally uni directional and so are not slowed by passengers attempting to board while others alight and vice versa Exceptions are locations where major transferring activity takes place between trains but these are limited Jamaica station on the Long Island Rail Road is one of the few examples of a station with major transfers as it serves as a funnel where eight lines converge from the east and two major lines diverge to the west Most transfers are made cross platform and are scheduled for two or three minutes SEPTA s four tra
30. of San Francisco s Muni Metro signaled grade separated light rail lines are rarely provided with the minimum headway capabilities represented by the capacity ranges in Exhibit 3 41 and Exhibit 3 42 Complete Procedure The complete procedure to estimate the peak hour capacity of grade separated rail transit requires sequential steps The first step is to determine the capacity limiting constraint either the station close in and dwell time or junction or turn back throughput The approach given at the start of this chapter The Weakest Link should be followed If necessary the junction or turn back throughput can be calculated from the methodologies and equations of Chapter 2 Should a junction or turn back appear to be the limitation on train throughput then the first recourse is to consider design or operating practice changes that will remove or mitigate such limitations In all but the most exceptional situations the limitation will be the close in dwell and operating margin time at the maximum load point station The complete procedure requires that the following values be calculated the close in time at the maximum load point station the dwell time at this station a suitable operating margin the peak 15 minute train passenger load and the peak hour factor to translate from the peak 15 minutes to peak hour CA Uo paces These procedures can be calculated manually or by experienced users developing their own comput
31. of Way with Grade Crossings 0 ceccescesecssecseecseeeeeeeeeeseeeecesecseesaecsaessaeaee 3 68 Signal Preemption aueh tee RENI EB ee ee inre pex 3 68 Grade Crossings and Station Dwell Times eee 3 68 Train Length and Station Limitations nennen 3 69 Street Block Length ck 5 io teed ie CSA e EET oh Eee a EEEE EEEE ei 3 69 Station Limitatiofs cete teer enter ederet poteet eee teet eese cs 3 69 Wheelchair Accessibility Effects eene nenne enne 3 70 IntrodUCtOn 3 Sese Rot eR eia iiie e ete e 3 70 High Platforms arae Er RE d OR I ed ae 3 71 LowsEloor Cats rp elsi Ripe 3 73 Capacity Determination Summary sese nenne 3 74 8 COMMUTER RAIL CAPACITY eese esses enses en sento seta tuse tatnen sesta sea tu 3 77 Introductio cote matu RO en Sha ae Gee ead 3 77 Train Thro ghput eerte tte ree iret ee ipei erts 3 77 Station COnStralbls 5c ERI gent eden dee eR E eT 3 78 Station Dwell i icc 2 ca tete te ttt suds eere tertie ice gea utn 3 79 Tram Capacity adeb ei Shree ee Rev des Se A ee 3 80 9 AUTOMATED GUIDEWAY TRANSIT CAPACITY ecce eee 3 83 Introduction o ee A eet me eee eie eet 3 83 Train Control Separation n iere tee pet pier io eerie ie E tp cip ban 3 83 Passenger Flow Rates and D wells tert eet reete a 3 85 Loading Levels eed aee eR tiet eai ee eec 3 85 Off Line Stations aee IRIespeeivedeu eri hist ieee 3 86 IMHUU
32. quarters of rail transit accidents or incidents has resulted in new train control systems using automation to reduce or remove the possibility of human error Automatic train control adds further features to the train protection of basic signaling including automatic driving and train supervision that regulates service This chapter describes and compares the separation capabilities of various rail transit train control systems It is applicable to the main rail transit grouping of electrically propelled multiple unit grade separated systems All urban rail transit train control systems are based on dividing the track into blocks and ensuring that trains are separated by a suitable and safe number of blocks Train control systems are then broken down into fixed block and moving block signaling systems FIXED BLOCK SYSTEMS In a fixed block system trains are detected by the wheels and axles of a train shorting a low voltage current inserted into the rails The rails are electrically divided into blocks The blocks will be short where trains must be close together for example in a station approach and can be longer between stations where trains operate at speed The signaling system only knows the position of a train by the simple measure of block occupancy It does not know the position of the train within the block it may have only a fraction of the train front or rear within the block At block boundaries the train will occupy two
33. range design capacity after decades of growth A difficult question is what ultimate capacity a rail transit system should be designed for Certain transportation models can predict passenger demand for several decades ahead However predictions beyond 10 to 15 years are of decreasing accuracy particularly in areas without an existing rail transit system or good transit usage The resulting uncertainty makes the modal split component of the model difficult to calibrate When modeling does not provide a reasonable or believable answer it is possible to fall back on an old rail transit rule of thumb namely to design for three times the initial mature capacity Mature capacity occurs five to ten years after a system opens when extensions and branches are complete modal interchanges bus feeders and park and ride have matured and some of the rail transit initiated land use changes including development and densification around stations have occurred The achievable capacity determined from this manual can be used to establish the train and station platform lengths and the type of train control that will allow this long term demand to be met whether obtained from a long range model or by rule of thumb This long term demand may be 30 to 50 years ahead If this suggests that 180 m 600 ft long trains and platforms will be required then it does not mean they have to be built initially Stations can be designed to have platforms expanded in
34. sections determined by the procedures of this chapter This is due to two reasons Several light rail systems converge surface routes into a signaled grade separated section operating at or close to capacity Other less busy systems have the signaled grade separated sections designed economically not for minimum headways down to two minutes Typically this signaling is designed for three to four minute headways more restrictive than the headway limitations of on street operation with or without varying forms of traffic signal pre emption However signaled grade separated sections may not always be the prime headway limitation Chapter 7 explains how to calculate and determine the weak link in the capacity chain for light rail Determining the weak link in the capacity chain is also the starting point in this chapter with respect to this main category grade separated rail transit THE WEAKEST LINK Chapter 2 Train Control and Signaling developed the methodology for the train control system maximum throughput in three situations 1 the close in time at the busiest station 2 junctions and 3 turnbacks In new grade separated rail systems capacity should not be limited by junctions or Junctions and turnbacks turnbacks Both can be designed to avoid constraints Chapter 2 shows that a flat junction can handle 200 m 660 ft trains with standard rail transit performance under fixed block train control on non interference hea
35. service For these reasons the popularity of lifts and other special devices for the mobility impaired is decreasing in favor of more reliable and less exclusionary methods such as low floor cars Reducing the delays associated with wheelchair boardings and alightings is an important issue where capacity is constrained and is a particular concern on lines with single track or operating on a tight schedule Part 3 RAIL TRANSIT CAPACITY Page 3 70 Chapter 7 Light Rail Capacity Transit Capacity and Quality of Service Manual Exhibit 3 54 illustrates the various kinds of wheelchair access provided in the U S and Canada These access methods are discussed in detail in the following sections Exhibit 3 54 Wheelchair Access Examples High Level San Francisco Light Rail Low Floor Car Portland OR Mini High Platform Sacramento Curbside Lift Portland before low floor cars Car Mounted Lift San Diego Curbside Lift San Jose High Platforms High platforms allow level movement between the platform and the car floor This allows universal access to all cars of a train and removes the reliability and exclusionary effects associated with lifts ramps and special platforms Passenger flow is speeded for all passengers since there are no steps to negotiate on the car High platform stations can be difficult to fit into available space and can increase costs Nevertheless high platforms are used exclusively on a number of systems i
36. service rolling stock Fourth and finally a three track terminal station can handle exceptional passenger flows from trains on headways below 90 seconds On new systems turn backs can be disregarded as a capacity constraint unless economic circumstances or labor practices prevent an optimal terminal design Only in such exceptional circumstances is it necessary after determining the minimum headway from this chapter to apply Equation 3 7 to ensure that adequate terminal time is provided to allow for the anticipated passenger flows and the train operator to change ends On older systems terminal station design may be less than optimal and Equation 3 7 should be checked with the actual station cross over geometry to ensure there is adequate terminal time This calculation should then be cross checked with actual field experience In either case a turn back constraint is only likely if all trains use the terminal station If peak period short turns are operated such that only a proportion of trains use the terminal station then a rail line s capacity limitation can be assumed to be the close in movement at the busiest station GROWTH AND ACHIEVABLE CAPACITY The achievable capacity as defined in this manual is not the capacity which a rail transit line will provide on opening day or reach after a decade It is the maximum achievable capacity when the system is saturated and provided with a full complement of rolling stock That is the long
37. the current installation is reliable with a failure rate of about one in 400 operations Boarding and alighting times with the car mounted lifts are around one minute for each passenger movement However the need for the train operator to leave the cab to operate the lift adds to the time required and can mean the total station dwell time extends to 15 2 minutes when the lift is used If the operator is required to assist in tying down the wheelchair the dwell can be further extended Platform Mounted Lifts Platform mounted lifts are used on the San Jose light rail system They offer advantages over car mounted lifts in that all car doors are left available for other passengers when the lift is not required the lift is not subject to car vibration and the failure of a lift need not remove a car from service Disadvantages include increased susceptibility to vandalism and an increase in the distance that the train operator must walk to operate the lift For the San Jose system wheelchair handling is slow because of their wayside lift arrangement The lift is stored vertically in an enclosed housing at the front of each platform To operate the lift the train operator must raise sliding steel doors on each side of the lift housing lower the car side of the lift to floor level lower the platform side to ground level have the passenger board the lift raise the lift and board the passenger store the lift and secure the housing This procedu
38. the station stopping point Then compare this speed restriction with the normal approach speed at that distance from the station as shown in Exhibit 3 7 The most restrictive approach speed must then be entered in Equation 3 4 Exhibit 3 6 Speed Limits on Curves and Switches Speed limit km h 0 20 40 60 80 100 120 140 160 180 200 Curve radius m Part 3 RAIL TRANSIT CAPACITY Page 3 14 Chapter 2 Train Control and Signaling Transit Capacity and Quality of Service Manual Exhibit 3 7 Distance Speed Chart An alternative version of this figure in U S customary units appears in Appendix A 300 250 200 150 100 Stopping distance m 50 Speed km h Two other factors affect minimum headways Grades into or out of a station will change the acceleration and braking rates Line voltage will drop below the nominal value on heavily used systems and reduce train performance The results of grades and voltage drops are shown in Exhibit 3 8 and Exhibit 3 9 respectively The calculations of these effects are complex and best left to a computer simulation If a simulation model is not available then the approximate headway changes can be read from Exhibit 3 8 and Exhibit 3 9 and the calculation from Equation 3 4 adjusted by the number of seconds Exhibit 3 8 Effect of Grade on Station Headway 150 140 130 120 Headw ay seconds 110 100 0 1 2 3 4 5 6 7 8 9 10 Grade percent NOTE cab signa
39. transit line is to find the weakest link the location or factor that limits the capacity of the entire line SELECTING THE WEAKEST LINK Determining the capacity of light rail transit lines is complicated by the variety of rights of way that can be employed In the simplest case a grade separated right of way is used and the capacity calculation techniques given in Chapter 6 can be applied However most light rail transit lines use a combination of right of way types which can also include on street operation often in reserved lanes and private right of way with grade crossings Other limitations can be imposed by single track sections and the street block lengths The line capacity is determined by the weakest link this could be a traffic signal with a long phase length but is more commonly the minimum headway possible on a block signaled section The first portion of this chapter discusses the capacity limitations imposed by right of way characteristics The right of way capacity constraints are discussed in the following sections in the order of their decreasing relative importance for most systems This order is as follows e single track e signaled sections e on street operation and e private right of way with grade crossings This order is not definitive for all systems but it is appropriate for most System specific differences such as short block lengths on signaled sections will change the relative importance of each i
40. vice versa in the afternoon Shorter trains may be used at the extremities of the peak period In this case the total number of seats provided over the peak hour must be determined and the peak hour factor applied Where the rolling stock design is unknown the number of seats per unit length of train can be used based on the shortest platform where the service will stop A number of systems particularly the older ones operate trains which exceed the platform length at a number of stations This situation is particularly common where platforms are constrained by physical and built up features Passengers must take care to be in the correct car s if alighting at a station with short platforms Train length on electric lines can also be limited by the amount of current the overhead or third rail is able to supply Exhibit 3 57 shows the number of seats and seats per meter length of selected North American commuter rail cars All cars have substantially the same outside dimensions the AAR passenger car maximums of 25 2 m 82 7 ft long and 3 2 m 10 5 ft wide Passenger loads range from over 7 to below 2 passengers per meter of car length 2 1 to 0 6 p ft of car length At the high end are the double deck car types bi levels 2 and gallery cars A 2 3 seating configuration is needed to reach 7 passengers per meter length 2 1 p ft length Such seating is not popular with passengers and the middle seats are not always occupied with some pas
41. 0 9 seconds with a variable safety distance moving block system and automatic train operation 2 In Chapter 6 Grade Separated Systems Capacity four methods were shown for Determine dwell using simple determining the controlling dwells Method 2 Using Existing Dwell Data is not applicable method to a new system The simplest option is to use Method 1 which recommends a range of dwell values from 35 to 45 seconds If there are no indications of any single very high volume stations where the more complicated dwell calculations should be used then a median value of 40 seconds can be selected In Chapter 5 Operating Issues it was suggested that the more operating margin that can Determine operating margin be incorporated in the headway the better with 20 to 25 seconds as the best guide Here 25 seconds is selected to provide better reliability The total of the controlling dwell at the busiest station and the operating margin is then 65 seconds Adding this to the minimum train separation times calculated above results in minimum headways of 116 1 and 97 4 seconds respectively These should be rounded up to an integral number of trains per hour that is 120 seconds 30 trains per hour and 100 seconds 36 trains per hour 3 Exhibit 3 25 indicates the lower level of heavy rail car loading at 7 passengers per linear meter of train length inclusive of diversity allowances At this more conservative loading the specified train of eigh
42. 00 m 660 ft train 3 21 Exhibit 3 14 Headway Components for Cab Control Signaling with a 120 Second Headway iot s sim ttt erret re e getestet eret NS 3 21 Exhibit 3 15 Dwell Time Components of Four Rail Transit Stations 3 24 Exhibit 3 16 Selection of Rail Transit Door Flow Times eese 3 25 Exhibit 3 17 Summary of Rail Transit Average Door Flow Times 3 26 Exhibit 3 18 BC Transit SkyTrain Door Flow Rate Comparisons 3 26 Exhibit 3 19 Quadruple Stream Doorways eese eene 3 27 Exhibit 3 20 Controlling Dwell Data Limits seconds eese 3 28 Exhibit 3 21 Passenger Space on Selected North American Heavy Rail Systems 3 29 Exhibit 3 22 Male Passenger Space Requirements ssseeeeeee 3 30 Exhibit 3 23 Schematic LRT Car Showing Dimensions seeeeeee 3 33 Exhibit 3 24 Linear Passenger Loading Articulated LRVS esses 3 33 Exhibit 3 25 Linear Passenger Loading Heavy Rail Cars esses 3 34 Exhibit 3 26 Summary of Linear Passenger Loading p m sss 3 34 Exhibit 3 27 Peak Hour Passenger Distribution Between Cars of Trains 3 35 Exhibit 3 28 Individual A M Train Loads TTC Yonge Subway Wellesley Southbound Jan 11 1905 et esee roe tre nne tede PERO ORDERS P
43. 27 8 m s v line speed in m s 27 8 m s 100 km h 6 0 seconds ts switch throw and lock time seconds 45 seconds lom operating margin seconds Transit Capacity and Quality of Service Manual Example Problem 3 The Situation A busy heavy rail line operates through a major interchange Heavy rail with long dwell station with long station dwell times The Question What is the maximum passenger carrying capacity through this station The Facts Y A generous loading standard means more passengers seated Y Service is provided by 10 car trains with each car being 22 8 m long Y The transit agency s loading standard is 6 passengers per meter of car length Y The dwell time at the controlling dwell station averages 30 seconds with a standard deviation of 21 seconds There is a 1 5 percent downgrade into the station The line is automated using moving block signaling Train operators are responsible for closing the doors and initiating acceleration this delay is incorporated into the dwell time Y Assume that trains are evenly loaded over their length SSS Outline of Solution The solution consists of three key steps a determining the train capacity b determining the minimum train separation based on the signaling system and train length and c incorporating the station dwell time and an operating margin To determine the minimum headway allowances for dwell time and an operating margin must be added to the minimum train sep
44. 4 59 20 Commuter Rail 4 8 4 5 0 7 Heavy Rail 6 8 6 3 2 0 Heavy Rail less New York 5 5 5 6 1 5 NYCT alone 7 9 7 8 1 8 Part 3 RAIL TRANSIT CAPACITY Page 3 34 Chapter 4 Passenger Loading Levels Transit Capacity and Quality of Service Manual LOADING DIVERSITY Passengers do not load evenly into cars and trains over the peak hour Three different types of loading diversity have to be considered The first level of loading diversity is within a car In individual cars the highest standing densities occur around doorways the lowest at the end of the cars Several European urban rail systems add doors sometimes only single stream at the car ends to reduce this unevenness A second level of diversity occurs in uneven loading among cars of a train Cars that are closer to station exits and entrances will be more heavily loaded than more remote cars This inefficiency can be minimized by staggering platform entrances and exits between ends centers and third points of the platforms This is not always possible or practiced Even so relatively even loading often occurs due to the duress factor that encourages passengers to spread themselves along the platform during heavily traveled times or risk being unable to get on the next arriving train Few systems count passengers by individual cars when these are crush loaded This is difficult to do with any accuracy and the results differ little from assigning a set full load to
45. 5 Operating Issues Transit Capacity and Quality of Service Manual Exhibit 3 32 shows the headway components with the final column indicating the residual time that is a surrogate for the operating margin Exhibit 3 33 shows this data graphically with the operating margin as the top component of each bar The bars are arranged in order of increasing headway Note that the bar furthest to the right is the only off peak data set It is included only for comparison and shows the large operating margin available when a system is not at capacity The operating margins range widely and bear little relationship to system technology or loading levels Exhibit 3 32 Dwell and Headway Data Summary of Surveyed North American Heavy Rail Transit Lines Operating at or Close To Capacity 1995 Avg Train Estimated Station Avg Dwell Control Operating Station amp Dwell Dwell Hdwy as of Separation Margin System amp City Direction s SD s s BART Embarcadero San Francisco WB 49 9 19 7 201 7 CTS 1 St SW Calgary WB 34 6 11 1 176 6 19 6 80 0 39 9 CTS 3 St SW Calgary EB 40 0 16 2 181 4 22 1 80 0 28 9 CTS City Hall Calgary EB 36 8 206 1914 192 80 0 33 4 Muni Montgomer eee UE T 344 11 0 146 0 23 6 60 0 29 6 NYCTA Queens Plaza New York WB 40 7 17 3 134 7 30 2 53 0 6 4 NYCTA Grand Central New York SB 64 3 16 7 164 7 39 0 53 0 14 1 NYCTA Grand Ce
46. 8 Diversity of Peak Hour and Peak 15 Minute Loading System amp City Routes Peak Hour Factor Commuter Rail CommuerRil mem S M LIRR New York 13 0 56 Mes Chicago 11 0 63 Metro North New York 4 0 75 NJT New tes 9 0 57 SEPTA Philadelphia 7 0 57 Light Rail CTS Calgary 2 0 62 RTD Denver 1 0 75 SEPTA Philadelphia 8 0 75 Tri Met Portland 1 0 80 Rapid Transit BC Transit Vancouver 1 0 84 CTA Chicago 7 0 81 MARTA Atlanta 2 0 76 MDTA Baltimore 1 0 63 NYCT New York 23 0 81 PATH New York 4 0 79 UM Montreal 4 0 71 TTC Toronto 3 0 79 1 Mainly diesel hauled not electric multiple unit 2 This figure is suspicious Step 7 Putting it all Together The final step in the complete method of determining a grade separated rail transit line s maximum capacity is to determine the closest minimum headway as the sum of the calculated value of the minimum signaling system train separation plus the calculated or estimated value of dwell time plus the assigned operating margin H i T s t t Equation 3 14 The maximum number of trains per hour Ta then is T _ 3 600 _ 3 600 mx g T s t t min Equation 3 15 The maximum capacity Cmax is the number of trains multiplied by their length and the number of passengers per unit length adjusted from peak within the peak to peak hour 3 600LP PHF C T LP PHF T s ta
47. 8 per person Pushkarev et al suggest gross vehicle floor area as a readily available measure of car occupancy recommending the following standards e Adequate 0 5 m 5 4 ft provides comfortable capacity per passenger space e Tolerable with difficulty 0 35 m 3 8 ft is the lower limit in North America with some touching e Totally intolerable 0 2 m 2 2 ft is the least amount of space that is occasionally accepted Commuter rail capacity is based on the number of seats Commuter rail cars in North America are typically 28 m 86 ft long and with few exceptions have seating for 114 to 185 passengers The higher levels relate to bi level or gallery cars and or cars with 2 3 seating arrangements Wheelchair space provisions range from 0 55 to 1 2 m 5 9 12 9 ft with 0 8 m 8 6 ft typical This space can include folding or jump seats Provision must also be made for wheelchair maneuvering and for any requirements to carry push chairs baggage and bicycles particularly on rail lines that serve airports More space is required for electric chairs and ones whose occupants have a greater leg inclination less for compact and sports chairs The vehicle capacity for existing systems should be based on actual loading levels of a comparable service Actual levels on a specific system or line should be adjusted for any difference in car size and interior layout particularly the number of seats Manufa
48. Alighting Rock Concert Alighting Peak Hour Alighting Peak Hour Boarding Off peak Mixed Flow Peak Hour Mixed Flow While most of the field data collection on doorway flow rates was done during peak periods off peak and special event flows were observed on BC Transit s SkyTrain and o e a 1 oa 2 Time per passenger per single stream seconds Page 3 26 Chapter 3 Station Dwell Times 2 5 Transit Capacity and Quality of Service Manual Special event flows were observed before a football game before a rock concert and on a busy suburban station in the early afternoon base period The resultant data are contrary to the supposition that special event crowds move faster and that off peak flows are slower than in the peak hour BC Transit has also measured car occupancy differences between normal peak hour operation and after service delays In the ensuing pressure to travel after a delay standing density almost doubled from a mean of 2 8 passengers per m to 5 passengers per m 3 8 to 2 2 ft p Effect of Door Width on Passenger Flow Times Extensive doorway flow data has failed to show any meaningful relationship between door width and flow rate within the 1 14 to 1 37 m 3 75 to 4 5 ft range of door widths observed all double stream doors are essentially equal Double stream doors frequently revert to single stream flows and very occasionally three passengers will move through the d
49. Capacity Transit Capacity and Quality of Service Manual The maximum number of trains per hour can be selected from the above two charts rounded down and multiplied by the selected train loading level obtained from Chapter 4 Passenger Loading Levels Exhibit 3 25 which shows a range of linear loading levels for heavy rail cars from 7 to 11 passengers per meter of length 2 1 3 4 p ft of length Exhibit 3 24 shows a range of linear loading levels for light rail cars from 5 to 9 passengers per meter of length 1 5 2 7 p ft of length These linear loading levels represent the peak 15 minutes and a peak hour factor should be applied if loading levels in the upper ranges of these charts are selected When calculating diversity on the capacity of a line in a city with existing rail transit of the same mode the existing peak hour factor or near equivalents should be obtained from Chapter 4 Passenger Loading Levels For new systems a peak hour factor of 0 8 is recommended for heavy rail and 0 7 for light rail Applying these loading levels to the throughput ranges above provides a direct range of passengers per peak hour direction per track versus train length shown in Exhibit 3 41 and Exhibit 3 42 Exhibit 3 41 Achievable Capacity with Multiple Command Cab Control Signaling System 40 000 38 000 36 000 34 000 32 000 30 000 28 000 26 000 24 000 22 000 20 000 18 000 16 000 14 000 Sooo F 1N iUo E d
50. Chapter 1 Rail Capacity Basics Transit Capacity and Quality of Service Manual 3600 Cp r PX ts et Equation 3 2 where Cp design capacity p h t minimum train separation s ty dwell time at the controlling station s Pc total passengers per car and Nc number of cars per train In turn the achievable capacity can be expressed as C C PHF Equation 3 3 where Ca achievable capacity p h Cp design capacity p h PHF peak hour factor The first expression in Equation 3 2 determines the number of trains per hour and is the inverse of the closest or minimum headway It determines train throughput at the controlling station usually the maximum load point station In rare cases speed restrictions or heavy mixed passenger flows may dictate that other than the maximum load point station controls train throughput The relevant minimum train separation in seconds is the minimum time from when a train starts to leave the most restrictive station usually the maximum load point station until the following train can berth at that station This is referred to as the close in time and is based on non interference with the following train i e no speed restrictions or stops In a small number of cases the critical governor of headway is a junction or a terminal maneuver Controlling dwell is based on actual station dwell time adjusted to a controlling value over the peak hour The controlling dwell may con
51. Improving Rail Transit Line Capacity Using Computer Graphics Logistics and Transportation Review Vol 17 No 4 University of British Columbia Faculty of Commerce December 1981 2 Anderson J Edward Transit Systems Theory Lexington 1978 3 Auer J H Rail Transit People Mover Headway Comparison IEEE Transactions on Vehicular Technology Institute of Electrical and Electronics Engineers 1974 4 Batelle Institute Recommendations en vie de l am nagement d une installation de transport compte tenu de donn es anthropom triques et des limites physiologiques de l homme Geneva 1973 5 Demery Leroy W Supply Side Analysis and Verification of Ridership Forecasts for Mass Transit Capital Projects APA Journal Summer 1994 6 Jacobs Michael Robert E Skinner and Andrew C Lerner Transit Project Planning Guidance Estimate of Transit Supply Parameters Transportation Systems Center U S Department of Transportation Washington DC 1984 7 Parkinson Tom and Fisher Ian Rail Transit Capacity TCRP Report 13 Transportation Research Board Washington DC 1996 8 Pushkarev Boris S Jeffrey M Zupan and Robert S Cumella Urban Rail in America An Exploration of Criteria for Fixed Guideway Transit Indiana University Press 1982 Part 3 RAIL TRANSIT CAPACITY Page 3 87 Chapter 10 References Transit Capacity and Quality of Service Manual This page intentionally blank Part 3 RAIL TRANSIT CA
52. ON LIMITATIONS Street Block Length The length of street blocks can be a major limitation for at grade systems which operate on street Most jurisdictions are unwilling to allow stopped trains to block intersections and so require that trains not be longer than the shortest street block where a stop is likely This issue is especially noteworthy in Portland where unusually short street blocks of 65 m 200 ft in the downtown area limit trains to two cars The San Diego Trolley also faced this issue when they operated four car trains on the East Line for a time Since three cars is the maximum that can be accommodated by the downtown blocks trains were split in two sections before entering downtown Sacramento is an exception to the street block length rule and is able to operate 4 car trains in the peak hours These long trains block one intersection when stopped This situation is almost a necessity as the extensive single track nature of the Sacramento line imposes a minimum headway of 15 minutes on the service The capacity limitation of this headway restriction is therefore partially made up for by the operation of relatively long trains Street block length is also an issue if another vehicle occupies the same lane used by light rail trains in a block If this would cause the rear of the train to protrude into an intersection then the train must wait for the block to clear before advancing This fact provides a strong argument for the provision o
53. PACITY Page 3 88 Chapter 10 References Transit Capacity and Quality of Service Manual 11 EXAMPLE PROBLEMS High Capacity Heavy Rail Heavy Rail Line with Junction Heavy Rail with Long Dwell Light Rail with Single Track Section Commuter Rail with Limited Train Paths Automated Guideway Transit with Short Trains Automated Guideway Transit with Off Line Stations PO OT com c Part 3 RAIL TRANSIT CAPACITY Page 3 89 Chapter 11 Example Problems Transit Capacity and Quality of Service Manual High capacity heavy rail Solution required for two signaling systems Example Problem 1 The Situation A transit agency is planning to build a heavy rail transit line and wants to determine the minimum train separation possible with a fixed block cab control signal system and with a variable safety distance moving block signaling system The Question 1 What is the minimum train separation ignoring station dwell time and operating margin effects with each type of signaling system 2 What is the minimum headway with typical dwells and operating margins 3 What is the resultant maximum capacity for a new system with higher quality loading standards The Facts The agency is planning to use trains consisting of a maximum of eight 24 5 m cars Trains will operate at a maximum of 100 km h 27 8 m s and will be travelling at 52 km h 14 4 m s when entering stations if the cab control system is chosen and at 55 km h 15 3 m s if
54. Passengers per Unit Train Length Major North American Rail Trunks 15 Minute Peak Length Avg PassJ System amp City Trunk Name Mode m Seats Pass Car m Ra New York 53rd Street Tunnel HR see note 50 70 197 227 10 4 NYCT New York Lexington Ave Local HR 15 6 44 144 9 3 Iver New York Steinway Tunnel HR 15 6 44 144 9 3 NYCT New York Broadway Local HR 15 6 44 135 8 7 lave Toronto Yonge Subway HR 22 7 80 197 8 7 NYCT New York Lexington Ave Ex HR 15 6 44 123 7 9 Det New York Joralemon St Tun HR 15 6 44 122 7 8 NYCT New York Broadway Express HR 15 6 44 119 7 6 Duct New York Manhattan Bridge HR 22 8 74 162 7 1 NYCT New York Clark Street HR 15 6 44 102 6 6 lee Calgary South Line LR 24 3 64 153 6 3 GO Transit Toronto Lakeshore East CR 25 9 162 152 5 9 SkyTrain Vancouver SkyTrain HR 12 4 36 73 5 9 PATH New York World Trade Center HR 15 6 31 92 5 9 PATH New York 33rd St HR 15 6 31 88 5 7 CTA Chicago Dearborn Subway HR 14 6 46 82 5 6 NYCT New York 60th Street Tunnel HR 22 8 74 126 5 5 Iver New York Rutgers St Tunnel HR 22 8 74 123 5 4 lene Calgary Northeast Line LR 24 3 64 125 5 1 CTA Chicago State Subway HR 14 6 46 75 5 1 CalTrain San Fran CalTrain CR 25 9 146 117 4 5 LIRR New York Jamaica Penn Sta CR 25 9 120 117 4 5 ete Chicago pees Electric CR 25 9 156 113 4 4 MARTA Atlanta
55. RAIL TRANSIT CAPACITY Page 3 96 Chapter 11 Example Problems Transit Capacity and Quality of Service Manual Example Problem 5 The Situation An existing commuter rail agency would like to expand its Commuter rail with limited train operations to a new route that is owned by a freight railroad paths The Question Based on the constraints given below can the commuter rail agency provide service on the new line with its current single level car fleet or must it order new double level cars for the line The Facts Y The freight railroad will only allow six commuter rail trains per hour to use its line Y Physical constraints mean that station platforms on the new line can be no more than eight cars in length Y The commuter rail agency currently uses single level cars that have 120 seats but is considering the purchase of two level cars with 180 seats although it would prefer to purchase more single level cars to maintain a standard fleet Y The agency has a policy of planning service based on cars being at 9096 of seated capacity Y The agency would like to be able to accommodate a flow of 6 000 passengers per hour in the peak hour Y Train scheduling can be adjusted to meet the peak 15 minute demand provided no more than six trains are operated per hour Y Trains are limited by railroad contract but can be spaced through the peak hour to best match demand Outline of Solution To determine which car type if either can satisfy t
56. RANSIT CAPACITY Exhibit 3 15 Dwell Time Components of Four Rail Transit Stations BART Montgomery Station San Francisco E1Wait to Dep El Doors Open o Pass Flow 0 10 20 30 40 50 60 DWELL seconds Average headway 153 seconds Number of passengers observed 586 Flow time averages 38 of total dwell BC Transit SkyTrain Burrard Station Vancouver Wait to Dep Doors Open O Pass Flow 0 10 20 30 60 DWELL seconds Average headway 153 seconds Number of passengers observed 586 Flow time averages 38 of total dwell Page 3 24 NYCT Grand Central Station New York Wait to Dep Doors Open OPass Flow 0 20 40 60 80 100 120 DWELL seconds Average headway 160 seconds Number of passengers observed 1 143 Flow time averages 64 of total dwell TTC King Station Southbound Toronto Wait to Dep Doors Open O Pass Flow 10 20 30 40 50 60 DWELL seconds Average headway 160 seconds Number of passengers observed 1 143 Flow time averages 64 of total dwell Chapter 3 Station Dwell Times Doorway Flow Rates Transit Capacity and Quality of Service Manual Exhibit 3 16 Selection of Rail Transit Door Flow Times SkyTrain Vancouver TTC Toronto SkyTrain SE Vancouver CTS Calgary BART San Francisco SkyTrain Vancouver Muni San Francisco ETS Edmonton MTS San Diego Tri Met Portland PATH New York SkyTrain Vancouver
57. Station Dwell Times for Heavily Used Systems seconds Total Median Median System amp City Station Pass Dwell s Headway s BART San Francisco Embarcadero CTS Calgary 1st St SW LRT CTS Calgary 3rd St SW LRT CTS Calgary City Hall LRT NYCT New York Grand Central 4 amp 5 SB NYCT New York Queens Plaza E amp F PATH Newark Journal Square Muni San Francisco Montgomery LRT SkyTrain Vancouver Broadway SkyTrain Vancouver Metrotown off peak TTC Toronto King TTC Toronto Bloor SB Southbound 2 298 48 0 155 0 Method 3 Using Dwells from the Same System This method is only applicable where a line of the same mode is being added to an existing system in which case the controlling dwell time from an existing similar peak point station can be used Where passenger volumes at the headway critical station of the new line are different from the equivalent station on an existing line the flow component of dwell time can be adjusted in proportion to hourly passenger movements in the station Alternatively the dwell time from an existing station with similar passenger volumes can be used Care should be taken if the train control system or operating procedures are different If this is the case consideration should be given to adjusting both the station dwell time and the operating margin Method 4 Calculating Dwells from Passenger Flows
58. TCRP Report 13 Rail Transit Capacity develops regression equations to relate passenger flow times to the number of boarding alighting or mixed flow passengers and in turn to convert this flow time to dwell time These regression equations can be used to estimate the dwell time from hourly passenger flows into the maximum load point station However the best regression fit involves logarithmic functions and the estimation of a constant for the ratio between the highest doorway and the average doorway passenger flow rate The mathematics are complex and it is uncertain if the results provide any additional accuracy that merits this complexity particularly if the hourly station passenger volumes by direction are themselves somewhat uncertain This method is best suited to new lines in locations without rail transit and with a sufficiently refined and calibrated regional transportation model that can assign hourly passenger flow by direction to individual stations The method is not detailed further in this manual and can be found in full in TCRP Report 13 8 Step 4 Selecting an Operating Margin Chapter 5 Operating Issues introduced the need to add an operating margin to the minimum train separation and dwell time to create the closest sustainable headway without interference Part 3 RAIL TRANSIT CAPACITY Page 3 58 Chapter 6 Grade Separated Systems Capacity Transit Capacity and Quality of Service Manual Ironically the closer the tr
59. The flow rate analysis showed that flat fare payments added one second per boarding passenger about 2596 to an up stairs board and 5046 to a level board This is an inefficiency that increases running time station by station day by day These factors however cannot be applied to the dwell time calculations of Chapter 3 Station Dwell times as the far more drastic impact is the restriction of boarding to a single staffed door If on board manual fare collection is used dwell times must be increased by the above percentages to arrive at achievable capacity A system using manual on board fare collection and restricting boarding to driver attended doors only cannot achieve its maximum capacity Stations with high mixed flows must also have platforms of adequate width to accommodate the flows Platform width is also a factor in making it easy for passengers to distribute themselves along the length of a train and so improve the loading diversity factor WHEELCHAIR ACCOMMODATIONS With dwell times being one of the most important components of headway the time for wheelchair movements is important Measured lift times run 2 3 minutes with some as low as 60 seconds Level wheelchair movements are generally faster than walking passengers except where the car or platform is crowded Level loading is essential to achieve high capacity Where high platforms or low floor cars cannot be provided mini high or high block loading arrangements for wheelchair
60. Transit Capacity and Quality of Service Manual PART 3 RAIL TRANSIT CAPACITY CONTENTS 1 RAIL CAPACITY BASICS eese esses enses tns en asta tuse ta sone ta sens tasses suse ta sone ta an 3 1 T trod tin C 3 1 inp I 3 1 The Bas168 etre EUROPEE tU a AER REA 3 2 Design versus Achievable Capacity essere 3 3 service Headway ot eU ORE aUe D HR UR RA 3 4 Line Capacity ient ORUM eeepc 3 5 Train Control Throughput esee nennen enne nnne 3 5 Commuter Rail Throughput essent 3 6 Staton Dwells eet nites e toro ect bte e rt Rp teh e rte reete 3 6 Tram Car Capacity eoo m En os tase cheb ERE e DE et 3 7 Introduction petere ter ates ae ae he eet ed eee tee 3 7 Car Capacity erecto ce nre ne re oe rt reri Or EREE EEST 3 7 Tram Capacity a eoque ette Vcn ted etna eerste 3 7 Station Svo rn EP 3 8 2 TRAIN CONTROL AND SIGNAL INQG esee ee eene seen tenen sns ta sns enses snae 3 9 TiO CUCTION MEE 3 9 Fixed Block Systems tec Ie ors re E et ives ee E RE E eerte Rehd un 3 9 Cab Signaling 4 i Nee aA eomeleve ete ee 3 10 Moving Block Signaling Systems essere 3 10 NEAL EET 3 11 Hybrid Systems oet Rete eed ettet pete tee eere 3 11 Automatic Train Operation sseseeseeeeeeeeeeee nennen eene rennen enne 3 11 Automatic Train Supervision sessseeeeeene
61. UM Montr al 2 6 3 2 4 0 3 4 Care should be taken in comparing and applying the service standards with hourly average loadings Service standards are usually based on the peak within the peak 15 minutes or less The difference between 15 minute and peak hour flows can be represented by a peak hour factor The peak hour factor for New York subway s trunk routes averages 0 817 Outside New York the peak within the peak period tends to be more pronounced and the peak hour diversity factor is lower In part this is due to the long established Manhattan program to stagger work hours and the natural tendency of passengers to avoid the most crowded period particularly on lines that are close to capacity In addition to standards or policies for the maximum loading on peak within the peak period trains and for standards based on minimum policy headways at off peak times some operators specify a maximum standing time This is more often a goal rather than a specific standard 20 minutes is typical Loading levels for commuter rail are unique and uniform Although standing passengers may be accepted for short inner city stretches or during times of service irregularities the policy is to provide a seat for all passengers Capacity is usually cited at 90 to 95 of the number of seats on the train Part 3 RAIL TRANSIT CAPACITY Page 3 29 Loading levels vary widely by transit mode and system Mexico City s Metro is an exception and experien
62. Y Page 3 4 Chapter 1 Rail Capacity Basics Transit Capacity and Quality of Service Manual Line Capacity Line capacity is the maximum number of trains that can be operated over a line in a peak hour Exhibit 3 1 Line Capacity Flowchart 3600 LINE CAPACITY minimum controlling maximum throughput in train station TRAINS HOUR separation dwell seconds seconds boarding height door no amp width fare collection wheelchair use formula for closest spacing different signalling types junction and turnback constraints Rapid transit and AGT and those parts of light rail and commuter rail that are equal to rapid transit i e double track grade separated electric Commuter rail not included in other category Light rail not included in other category l Low Loading High Loading Wheelchair Wheelchair Wheelchair Wheelchair Wheelchair via profiled via ramp at via ramp at via platform via vehicle platform 2nd stop main stop lift lift Not all wheelchair options apply to commuter rail As shown in Exhibit 3 1 throughput of the train control system and dwell time at stations are the two major factors in determining line capacity Both factors can be sub divided into the three categories based on alignment equipment train control and operating practices In turn light rail and commuter rail lines must be div
63. a moving block system is selected The distance from the front of a stopped train to the station exit block is 10 meters Assume that there are no grades into or out of stations and that no civil speed restrictions limit approach speeds to sub optimal levels Outline of Solution 1 To answer this question two equations must be used one for each signaling system type Equation 3 4 and Equation 3 6 may be found in Chapter 6 Note that the equations provide allowances for grades and line voltage effects that have been removed as they are not required to answer this question The values for all variables are summarized as follows r Value Term Description calculated T s train control separation in seconds 200 meters L length of the longest train 10 meters D distance from front of stopped train to start of station exit block in meters 14 4 m s cab cont station approach speed in m s 15 3 m s m block 27 8 m s p Vmax s maximum line speed in m s 27 8 m s 100 km h 75 K braking safety factor worst case service braking is K of specified normal rate typically 75 1 2 cab control B separation safety factor equivalent to number of braking 1 moving block distances surrogate for blocks that separate trains 3 0 seconds tos time for overspeed governor to operate on automatic systems driver sighting and reaction times on manual systems 0 5 seconds til time lost to braking jerk limitat
64. aged over the peak hour that is no loading diversity factor is required This provides a recommended linear loading level of 6 passengers per meter of train length 1 8 p ft for heavy rail and 5 p m 1 5 p ft for light rail An alternative approach is to base the loading levels on either the nominal capacity of a vehicle or the actual peak hour utilization The nominal capacity of vehicles whether specified by the operating agency or manufacturer is arbitrary and for identical vehicles can differ by a factor of almost two Exhibit 3 47 shows the actual peak 15 minute linear loading levels for major North American trunks again in descending order Discounting the uniquely high values in New York the remaining data offer realistic existing levels to apply in selecting a loading level for a comparable system or a new line in the same system with similar characteristics 16 A goal for an operating margin based on an average of one disturbed peak period per ten weekdays two weeks has been discussed with rail transit planners but has not been documented Dilemma on at capacity lines Nominal linear loading levels Actual linear loading levels Part 3 RAIL TRANSIT CAPACITY Page 3 59 Chapter 6 Grade Separated Systems Capacity Transit Capacity and Quality of Service Manual An alternative version of this figure in U S customary units appears in Appendix A Part 3 RAIL TRANSIT CAPACITY Exhibit 3 47
65. ain less than ideal for typical North American light rail systems with their extensive open segregated trackage CAPACITY DETERMINATION SUMMARY Calculating the capacity of light rail transit lines is a complex process because of the varieties of rights of way which can be employed for the mode The basic approach is to find the limiting factor or weakest link on the line and base the capacity on this point The limiting factor for each line could be street running with long traffic signal phases a section of single track or the length of signal blocks where block signaling is used The key factors to be considered are 1 Single track 2 Signaled sections Of particular importance where for cost reasons the signaling is not designed to allow minimum possible headway operation 3 On street operation Capacity effects are strongly related to the degree of priority given to light rail vehicles relative to other traffic 4 Private right of way with grade crossings The first step in the process is to check the headway capabilities of any single track section over 500 m 1 600 ft in length following the procedure given earlier in this chapter Then compare this with the design headway of the signaling system and with twice the longest traffic signal phase of any on street section Select the most restrictive headway in seconds and convert this into trains per hour by dividing into 3 600 The simple procedure provides a reasonable estimat
66. ains operate and the busier they are the more chance there is of minor incidents delaying service due to an extended station dwell time stuck door or late train ahead It is never possible to ensure that delays do not create interference between trains nor is there any stated test of reasonableness for a specific operating margin A very small number of rail transit lines in North America are operating at capacity and so can accommodate little or no operating margin On such lines operations planners face the dilemma of scheduling too few trains to meet the demand resulting in extended station dwell times and erratic service or adding trains to the point that they interfere with one another Striking a balance is difficult and the tendency in practice is to strive to meet demand equipment availability and operating budget permitting While the absolutely highest capacity is so obtained it is poor planning to omit such an allowance for new systems The greater the operating margin that can be incorporated in the headway the better systems running at maximum capacity have little leeway and the range of operating margins used in the simple procedure 20 to 25 seconds remains the best guide The recommended procedure is to aim for 25 seconds and back down to 20 or even to 15 seconds if necessary to provide sufficient service to meet the estimated demand Where demand is unknown or uncertain in the long term future when a rail line in planni
67. aration time The results of these steps can then be combined to produce the maximum capacity based on the parameters given a Determining the train capacity This step is very straightforward and is based on the number of cars in each train the length of each car and the number of passenger spaces per unit of car length 10 cars train 22 8 m car 6 passengers m 1 368 passengers train b Determining the minimum train separation This step requires use of Equation 3 6 Since consideration of station dwell times and the operating margin are deferred to the next step they are not included in the equation below L P 100 v H s B K 2d 1 0 1G a 1 0 1G t v C Mos Po et tti t 2v v EL a max where H s minimum train separation in seconds L length of the longest train in meters Pe E positioning error default 6 25 m Va 7 station approach speed in m s 55 km h 15 3 m s K braking safety factor worst case service braking is K of specified normal rate default 75 B separation safety factor equivalent to number of braking distances surrogate for blocks that separate trains default 1 Vmax maximum line speed in m s 80 km h 22 2 m s ag initial service acceleration rate in m s default 1 3 m s ds service deceleration rate in m s default 1 3 m s2 G grade into the station 1 5 Ts time for overspeed governor to operate default 3 0 seconds tor braking reaction time 0 f
68. at operating margin and schedule recovery times are most needed to correct service irregularities Part 3 RAIL TRANSIT CAPACITY Page 3 39 Allowance for operating variables Uniformity of train performance Operating margins Schedule recovery Operating margin examples Chapter 5 Operating Issues Transit Capacity and Quality of Service Manual Light rail headways on observed systems were generally sufficiently long that any irregularities reflected problems other than schedule interference between trains One of the closest on street headways is in Calgary shown at the top Additional examples of these dwell headway charts are contained in Chapter 6 of TCRP Report 13 Rail Transit Capacity n7 Part 3 RAIL TRANSIT CAPACITY Exhibit 3 31 Observed Rail Headways and Dwell Times CTS 3rd St SW EB Calgary Apr 25 1995 4 00 5 30 PI BC Transit Broadway EB Vancouver 180 EB Dwell Time s Headway s Average headway Page 3 40 CTS 1st St SW WB Calgary Apr 25 1995 7 30 8 50 AM BART Embarcadero WB San Francisco 450 400 350 300 250 200 150 Feb 8 1995 7 35 8 45 AM TTC Bloor NB Toronto Feb 7 1995 4 05 6 00 PM NB northbound SB southbound EB eastbound WB westbound Chapter
69. ation previously arrived at produces a station headway of 107 1 seconds which should then be rounded off to 112 5 seconds to provide an integral number of 32 trains per hour Part 3 RAIL TRANSIT CAPACITY Page 3 94 Chapter 11 Example Problems Transit Capacity and Quality of Service Manual Example Problem 4 The Situation A light rail line operates with a single track section The Question The Facts Y Service is provided by three car trains each car 28m long v Initial acceleration is 1 0 m s Y The single track section is 1250 m long with one intermediate stop Y The section is on a road with a speed limit of 50 km h What is the maximum possible service frequency Comments Y Itis assumed that there are no other longer single track sections on the line nor more restrictive limitations imposed by any signaled sections of the line or by any signalized intersections Outline of Solution The maximum possible service frequency is twice the travel time through the single track section plus an allowance for operational irregularities Steps Calculate the travel time over the single track section from Equation 3 17 a N 1 3V nax L tL N t t t t N ot t 2 d J r V nax S om where tst time to cover single track section s Lst length of single track section 1250 m L train length 84 m Ns number of stations on single track section 1 lg station dwell time 20 s Vmax E maximu
70. blocks simultaneously for a short time In the simplest two aspect block system the signals display only stop red or go green A minimum of two empty blocks must separate trains and these blocks must be long enough for the braking distance plus a safety distance The simplest system can accommodate a throughput approaching 24 trains per hour This does not provide sufficient capacity for some high volume rail lines Higher capacity can be obtained from combinations of additional signal aspects three is typical shorter block lengths and overlay systems that electronically divide blocks into yet shorter phantom sections for trains equipped for this overlay In this way conventional train control systems can support a throughput of up to 30 trains per hour with typical train length performance station dwells and operating margins Overlay systems can increase this throughput by 10 to 1596 A notable exception to this is in Russia where conventional signaling routinely handles 40 metro trains per hour This is achieved by tightly controlling station dwells to a maximum of 25 seconds and rigorous adherence to schedule using digital clocks in each station to display the seconds from the departure of the previous train New Moscow metro lines are being Functions of signaling Signaling technology is very conservative Signaling cannot protect from every eventuality Automatic train control Track circuits Fixed block system
71. case the signaling system design capacity should be used to determine the maximum throughput of trains Typical design headways of 3 to 3 minutes allow 20 and 17 trains per hour respectively ON STREET OPERATION Historically streetcar operation has achieved throughput in excess of 125 cars per hour on a single track in many North American locations Even now the Toronto Transit Commission schedules single and articulated streetcars at a peak 15 minute rate of over 60 cars an hour on Queen Street East in Toronto where several car lines share a four block stretch The price of this capacity is low speed congestion irregular running and potential passenger confusion at multiple car stops Despite this record on street operation is often raised as a major capacity constraint for modern light rail systems yet this is rarely the case on contemporary lines This is particularly true on most newer lines where light rail trains have exclusive use of road lanes or a reserved center median where they are not delayed by other traffic making turns queuing at signals or otherwise blocking the path of the trains Exclusive lanes for light rail are also being instituted on some of the older streetcar systems Even with these improvements in segregating transit from other traffic light rail trains must still contend with traffic signals pedestrian movements and other factors beyond the control of the transit operator The transit capacity in these situa
72. ce Manual 15 minute recommended loading levels The peak hour factor is not so included and must be used to adjust passenger volumes from the estimated design capacity to a more practical achievable capacity This important peak hour factor is discussed for each mode in the relevant chapter for calculating capacity for that mode In each chapter suitable values are recommended for use in calculating the maximum achievable capacity Exhibit 3 30 Diversity of Peak Hour and Peak 15 Minutes System City fofRoutes Peak Hour Factor Commuter Rail CalTrain San Francisco 1 0 64 GO Transit Toronto 7 0 49 Long Island Rail Road New York 13 0 56 MARC Baltimore 3 0 60 MBTA Boston 9 0 53 Metra Chicago 11 0 63 Metro North New York 4 0 75 NICTD Chicago 1 0 46 New Jersey Transit Newark 9 0 57 SCRRA Los Angeles 5 0 44 SEPTA Philadelphia 7 0 57 STCUM Montr al 2 0 71 VRE Washington DC i 2 0 35 Light Rail CTS Calgary 2 0 62 RTD Denver 1 0 75 SEPTA Philadelphia 8 0 75 Tri Met Portland 1 0 80 d Rapid Transit i SkyTrain Vancouver 1 0 84 CTA Chicago 7 0 81 MARTA Atlanta 2 0 76 Metrorail Miami 1 0 63 NYCT New York 23 0 81 PATH New Jersey 4 0 79 STCUM Montr al 4 0 71 TTC Toronto 3 L 0 79 Part 3 RAIL TRANSIT CAPACITY Page 3 37 Chapter 4 Passenger Loading Levels Transit Capacity and Quality of Service Manual This page intentionally blank Pa
73. ces loading that can exceed 8 passengers m 1 8 f p It is customary to express passenger space requirements in passengers per square meter in metric and in square feet per passenger in U S customary units even though this results in a reciprocal relationship Service standards are usually based on peak within the peak loads Peak hour diversity is lower in New York than most other cities Maximum standing time policies Chapter 4 Passenger Loading Levels Transit Capacity and Quality of Service Manual Passenger standing density Gross vehicle floor area Suggested minimum space Maximum full and crush loads SPACE REQUIREMENTS The Batelle Institute recommends comfort levels for public transport vehicles and provides details of the projected body space of passengers in various situations The most useful of these for rail transit capacity are shown in Exhibit 3 22 for males e Comfortable 2 3 passengers per m 5 4 to 3 6 ft p e Uncomfortable 5 passengers per m 2 2 ft p and e Unacceptable gt 8 passengers per m 1 3 ft p Exhibit 3 22 Male Passenger Space Requirements Situation _ Projected Area m Projected Area f Standing 0 13 0 16 1 4 1 7 Standing with briefcase 0 25 0 30 2 7 3 2 Holding on to stanchion 0 26 2 8 Minimum seated space 0 24 0 30 2 6 3 2 Tight double seat 0 36 per person 3 9 per person Comfortable seatin 0 54 per person 5
74. city by 2 to 4 4 An unsafe event may be referred to as a wrong side failure Communication can be made secure Hybrid systems can allow equipment not equipped for moving block operation to operate on lines signaled with moving blocks Automated train operation systems often also provide for manual operation The acceptance of driverless trains in transit service has been slow Automated train operation may provide a 2 to 4 capacity increase Part 3 RAIL TRANSIT CAPACITY Page 3 11 Chapter 2 Train Control and Signaling Transit Capacity and Quality of Service Manual Corrective measures to correct late running trains Predictive control The close in time is the main constraining factor on rail transit lines Computer simulations often provide the basis for accurate estimations of capacity AUTOMATIC TRAIN SUPERVISION Automatic Train Supervision ATS is generally not a safety critical aspect of the train control system At its simplest it does little more than display the location of trains on a mimic board or video screen in the central control or dispatcher s office Increasing levels of functionality are available In more advanced systems where there is automatic train operation computer algorithms are used to attempt to automatically correct lateness These are rare in North America and are generally associated with the newer moving block signaling systems A further level of ATS strategies is pos
75. city constraint for light rail The headway limitation is very simply twice the time taken to traverse the single track section plus an allowance for switch throw and lock unnecessary for spring switches or gauntlet track plus an operating margin to minimize the potential wait of a train in the opposite direction The time to cover a single track section is N D 3 L tL s V max t t ut TNI t 2 d J 7 s max T SM om Equation 3 17 N I time to cover single track section s Ly length of single track section m or ft L train length m or ft N number of stations on single track section tq average station dwell time on section s Vmax maximum speed reached m s or ft s d deceleration rate m s Or ft s ti jerk limiting time s tpr operator and braking system reaction time s SM speed margin and D operating margin s The results of applying Equation 3 17 are shown graphically in Exhibit 3 51 17 See Allen Duncan W Practical Limits of Single Track Light Rail Transit Operation in the bibliography 18 Gauntlet track interlaces the four rails without needing switches saving capital and maintenance costs and potential operating problems due to frozen or clogged switch points The disadvantage is that the single track section cannot be used as an emergency turn back reversing location Part 3 RAIL TRANSIT CAPACITY Page 3 64 Chapter 7 Light Rail Capacity
76. ck regional rail tunnel through Center City Philadelphia is one of the few North American locations where commuter trains run through from one line to another without terminating downtown SEPTA schedules provide a very generous time of 10 minutes for trains to make two station stops over this 2 3 km 1 4 mi line segment 2 Commuter rail station dwell times are dependent on the platform level and car door layout The busiest lines are equipped with high platforms and remotely controlled sliding doors as on rapid transit cars Single level cars often use conventional traps for high and low platform stations but these are time consuming to operate and require a large operating crew Cars used on lines with both high and low platforms can be fitted with conventional trap doors at the car ends and sliding doors for high platform use at the center of the car as on New Jersey Transit the South Shore in Chicago and the Mont Royal line in Montr al Most bi level and gallery cars are designed for low platforms and have the lowest step close to the platform for easy and rapid boarding and alighting Bi level cars of the type popularized by GO Transit feature two automatic sliding double stream doors per side allowing cars to be emptied in one to two minutes Gallery cars usually feature one exceptionally wide door 2 meters wide at the center of each side to allow rapid boarding and alighting with multiple passenger streams 23 While there are three sta
77. co Bay Area is automatically driven with door closure and departure performed manually the latter subject to override by the automatic train control NYCTA in New York and the TTC in Toronto are entirely manual subject only to a permissive departure signal The TTC has a safety delay between door closure and train departure BC Transit s SkyTrain in Vancouver B C is an entirely automatic system with unattended cars door closing and departure times are pre programmed This is evident from the exhibit which shows two services including a short turn service with shorter dwells that ends about half way down All data represent the heaviest used doorway s on the train The proportion of dwell time productively used for passenger movements ranges from 31 to 6446 of the total dwell time This presents a challenge in determining dwell times from the passenger volumes Dwells also vary depending on the operating practices of each system Several North American light rail and heavy rail systems are notably more expeditious at station dwells than their counterparts contributing to a faster and so more economic and attractive operation Ironically several automatically driven systems have sluggish station dwells in which expensive equipment and staff sit and wait long after all passenger movement has ended The high capacity rail systems in Europe and Asia particularly those of Russia and Japan are noted for their efficient management and control of s
78. control separation in seconds 200 m 660 ft L length of the longest train 10 m 33 ft D distance from front of stopped train to start of station exit block in meters or feet calculated y station approach speed in m s or ft s 27 8 m s 88 ft s maximum line speed in m s 27 8 m s 100 km h maximum line speed in ft s 88 ft s 60 mph 75 K braking safety factor worst case service braking is K of specified normal rate typically 75 2 4 three aspect B separation safety factor equivalent to number of braking distances 1 2 cab control surrogate for blocks that separate trains 1 moving block 3 0 seconds t time for overspeed governor to operate on automatic systems to be replaced with driver sighting and reaction times on manual systems 0 5 seconds tj time lost to braking jerk limitation 1 5 seconds thr brake system reaction time 1 3 m s 4 3 ft s a _ initial service acceleration rate 1 3 m s 4 3 ft s d service deceleration rate 0 G grade into station downgrade negative 0 G grade out of station downgrade negative 90 L line voltage as percentage of specification 6 25 m 20 5 ft P positioning error moving block only 50 m 165 ft S Moving block safety distance moving block only L The equation for three aspect and cab control signaling systems derived from Equation 3 4 in Chapter 2 with dwell and operating margin components removed and grad
79. control system plus an allowance for switch operation lock and clearance and a reduced operating margin Morgantown and certain other AGT systems use on vehicle switching techniques where even this allowance typically 6 seconds can be dispensed with In theory trains or single vehicles can operate at or close to the minimum train control separation which can be as low as every 15 seconds refer to Exhibit 3 60 Major stations with high passenger volumes may require multiple platform berths otherwise partial dwell times must be added to the train separation times to obtain the minimum headway The achievable capacity of such specialized systems should be determined through consultation with the system manufacturer or design consultant 26 Systems with multiple platform terminal stations could be regarded as a sub set of off line stations The Mexico City Metro and PATH New York are examples of such arrangements Not coincidentally these two systems achieve respectively the highest passenger throughput and the closest regular headway on the continent for two track rail transit systems 27 Operating margins are intended to accommodate irregularities in train control separation and dwell times Off line stations remove the need to allow for dwell time variations Part 3 RAIL TRANSIT CAPACITY Page 3 86 Chapter 9 Automated Guideway Transit Capacity Transit Capacity and Quality of Service Manual 10 REFERENCES 1 Alle P
80. covery an amount of time added to the terminal turn around time to allow for recovery from accumulated delays on the preceding trip Schedule recovery time has some effect on achievable capacity and has economic implications as it can increase the number of trains and staff required to transport a given volume of passengers OPERATING MARGINS A starting point for recommending suitable operating margins to incorporate into the determination of the maximum achievable capacity are the operating margins incorporated into the schedules of existing systems The maximum load point peak period station dwell time and headways for several rail transit lines are presented in Exhibit 3 31 The headways in Exhibit 3 31 for Calgary are all multiples of the 80 second traffic signal cycle The seemingly erratic headways in Calgary are misleading as three routes forming two interlaced services share this downtown bus and light rail mall The exhibit also shows the dwell and headway regularity of interlaced services on BC Transit s fully automatic SkyTrain and more erratic operation on BART where there is automatic train operation but poor control of station dwells and headways The lower four charts in Exhibit 3 31 show the range of dwell and headway irregularities on manually driven systems These are not typical of most heavy rail lines throughout the day but represent lines at or near capacity at the peak point in the peak period It is at these times th
81. cturer specified passenger loading total maximum full or crush load does not necessarily represent a realistic occupancy level Rather it reflects applying a set criteria such as 5 or occasionally 6 passengers per square meter 2 2 to 1 8 ft p to the floor space remaining after seating space is deducted In particular crush load can represent the theoretical and often unattainable loading used to calculate vehicle structural strength or the minimum traction equipment performance Part 3 RAIL TRANSIT CAPACITY Page 3 30 Chapter 4 Passenger Loading Levels Transit Capacity and Quality of Service Manual Vehicle Specific Calculations Detailed calculations of the person capacity of individual vehicles are not recommended Given the wide range of peak hour occupancy that is dependent on policy decisions elaborate determination of interior space usage is generally not practical Reasonably accurate estimates of vehicle capacity are all that are needed The following procedures offer a straightforward method The first step after obtaining the interior car dimensions is to determine the length of the car side free from doorways Deducting the sum of the door widths plus a setback allowance of 0 4 m 16 inches per double door from the interior length gives the interior free wall length Seating can then be allocated to this length by dividing by the seat pitch e 0 69 m 27 inches for transverse seating and e 0 43 m 17 inches fo
82. cy at the station level can be poor particularly if there is more than one station in a zone Nevertheless this is often the sole source of individual station volumes and without it selection of the maximum load point station requires an educated guess Step 2 Determining the Control System s Minimum Train Separation Chapter 2 Train Control and Signaling developed the methodology for determining the minimum train separation with three types of train control systems each providing progressively increased throughput 1 three aspect signaling system 2 multiple command cab control and 3 moving block signaling system Although the equations appear long the arithmetic is simple and can be implemented using basic functions in a spreadsheet Before going to this effort check the availability of the required input parameters in Exhibit 3 43 Parameters can be adjusted for system specific values or left at their default value Train length is the most important variable However if most parameters are left at their default values then it would be simpler to refer to Exhibit 3 44 which shows the minimum train control separation against length for the three types of train control system Part 3 RAIL TRANSIT CAPACITY Page 3 53 Chapter 6 Grade Separated Systems Capacity Transit Capacity and Quality of Service Manual Exhibit 3 43 Minimum Train Separation Parameters BE Default value Term Description calculated l T s train
83. d Station Dwell Times Grade crossing activation and occupancy times can be affected by the presence of a station adjacent to the crossing If the train must use the crossing after stopping at a station the activation of the crossing signals is often premature and the crossing is unavailable to other traffic for more than the optimum time In this case the train is also starting from a stop and so must accelerate through the crossing adding to the total delay Where the station platform is on the far side of the crossing the arrival time at the crossing can be predicted consistently and premature activation of the crossing is not a factor The train is also either coasting or braking through the crossing from cruising speed and so will occupy it for less time Stations can be designed to place both platforms on one side of the crossing or to locate one platform on each side of the crossing such that trains use the crossing before stopping at the station Both arrangements are shown in Exhibit 3 52 Using far side platforms is advantageous for the operational reasons given above reduced right of way requirements and for median operation allowing left turn bays to be readily incorporated into the street Exhibit 3 52 Light Rail Platform Options at a Crossing l Facing Far side Part 3 RAIL TRANSIT CAPACITY Page 3 68 Chapter 7 Light Rail Capacity Transit Capacity and Quality of Service Manual Delays caused by premature acti
84. d to a frequency as calculated by Equation 3 17 and line capacity is reduced As an example if normal service is a train every 5 minutes and a 1250 m section of single track is used to pass an obstruction service will be limited to 7 2 minutes Nominal capacity will be reduced from 12 to 8 trains per hour or by one third This reduction is Part 3 RAIL TRANSIT CAPACITY Page 3 95 Maximum light rail frequency with a long single track section A self guiding spreadsheet with this equation and instructions may be available on the American Public Transit Association s TCRP dissemination web site at http www apta com A 7 2 minute headway is often expressed in transit timetables as service every 7 8 minutes Single track working in emergencies Chapter 11 Example Problems Transit Capacity and Quality of Service Manual Capacity reduction with single track working Changes in minimum single track headway with length not including rounding up to clock headway or adding an allowance for schedule irregularity sufficiently small that it may be accommodated temporarily by accepting higher levels of crowding Passengers are generally willing to accept this in emergency conditions Longer single track sections will reduce capacity further This loss may be made up where operational policies and signaling systems permit by platooning cars over the single track section Two of three trains can follow each other closel
85. data can be collected at busy stations to allow the mean and standard deviation to be calculated Both one and two standard deviations have been used in other work In either case it is necessary to ensure that the calculated controlling dwell time contains a sufficient allowance or margin to compensate for minor irregularities in operation With the Door widths on observed systems seemed to have little effect on flow rates All observed doors were essentially double stream Relating passenger volumes and flow rates and times to dwell times Part 3 RAIL TRANSIT CAPACITY Page 3 27 Chapter 3 Station Dwell Times Transit Capacity and Quality of Service Manual addition of one standard deviation some additional allowance for operational irregularities is necessary With the addition of two standard deviations the need for any additional allowance is minor or unnecessary In many situations particularly new systems insufficient data is available to estimate the dwell standard deviation over a one hour or even a 15 minute peak period In these cases or as an alternate approach in situations where data is available an operational allowance or margin can be added to the estimated dwell time due to a specific volume of passenger movements The results on controlling dwell times of adding 15 and 20 second operating margins on existing systems are shown in Exhibit 3 20 Exhibit 3 20 Controlling Dwell Data Limits seconds
86. dequate or comfortable loading level 11 243 seating is only possible on cars with width greater than 3 meters 10 feet not applicable to light rail or automated guideway transit Part 3 RAIL TRANSIT CAPACITY Page 3 32 Chapter 4 Passenger Loading Levels Transit Capacity and Quality of Service Manual S single setback allowance ft or m 0 2 m 0 67 ft or less and Sw seat pitch ft or m 0 69 m 2 25 ft for transverse and 0 43 m 1 42 ft for longitudinal L Number of doorways D 4 Ws Exhibit 3 23 Schematic LRT Car Showing Dimensions Default Method A default method is to divide the gross floor area of a vehicle exterior length x exterior width by 0 5 m 5 4 ft and use the resultant number of passengers as the average over the peak hour without applying a vehicle loading diversity factor An average space over the peak hour of 0 5 m 5 4 ft per passenger is the comfortable loading level on U S rail transit systems recommended in several reports and is close to the average loading on all trunk rail transit lines entering the CBD of US cities LENGTH Another default method to approximate loading levels is to assign passengers per unit length Applying Equation 3 9 produces loading levels in passengers per unit length for two typical light rail vehicles as shown in Exhibit 3 24 As would be expected the wider and longer Baltimore car has proportionately higher loadings per meter of length
87. dways down to 102 seconds plus an operating margin The equivalent time for the same length trains with a moving block signaling system is 63 seconds plus an operating margin Chapter 2 recommends that junctions controlled by a three aspect signaling system should be grade separated where trains combine to a joint headway below 3 minutes Only where there are flat junctions with headways for their respective train control systems below these levels plus a 20 second operating margin is it necessary to utilize Equation 3 8 to determine the junction throughput limitation Chapter 2 similarly shows that a two track terminal station can turn 200 m 660 ft trains every 120 seconds with a terminal time of 175 seconds that is the time required for passenger flows and for the driver to change ends on each train Chapters 2 and 5 suggest a number of measures to maximize capacity First where passenger flows are Part 3 RAIL TRANSIT CAPACITY Page 3 47 Chapter 6 Grade Separated Systems Capacity Transit Capacity and Quality of Service Manual The close in at the busiest station is commonly the weakest link Design for mature capacity heavy dual faced platforms can be provided Second where changing ends is a limitation then crew set backs should be used Third greater operational flexibility and improved failure management is obtainable by providing turn back capability both ahead of and behind the station with a storage track for spare or out of
88. dwell time Grax longest cycle length s in the line s on street section ta dwell time s at the critical stop te clearance time between trains s defined as the sum of the minimum clear spacing between trains typically 15 20 seconds or the signal cycle time and the time for the cars of a train to clear a station typically 5 seconds per car Za one tail normal variate corresponding to the probability that queues of trains will not form from Exhibit 2 15 and Cy coefficient of variation of dwell times typically 40 for light rail while streetcars running in mixed traffic have c values similar to buses Heritage streetcar operation The minimum sustainable headway is double the longest traffic signal cycle Some transit agencies use the signal cycle time C as the minimum clearance time Part 3 RAIL TRANSIT CAPACITY Page 3 67 Chapter 7 Light Rail Capacity Transit Capacity and Quality of Service Manual Pre emption delays Grade crossings adjacent to stations Far side platforms can be advantageous RIGHT OF WAY WITH GRADE CROSSINGS Private right of way with grade crossings is the predominant type of right of way for many light rail transit systems This can take the form of a route which does not follow existing streets or one which runs in the median of a road physically separated from other traffic except at crossings Capacity on lines with full signal pre emption can be determined usin
89. e PASSENGER ACTUATED DOORS The majority of new North American light rail systems use passenger actuated doors increasing comfort by retaining interior heat or air conditioning and reducing wear and tear on door mechanisms The practice can extend station dwell time but is of little value at higher capacities or busy stations where the use of all doors is generally required Consequently some systems use the feature selectively and allow the train operator to override passenger actuation and control all doors when appropriate A typical heavy rail transit car door will open and close in five seconds Certain light rail doors associated with folding or sliding steps can take double this time in their operation Obviously a door opening initiated at the end of a station dwell will extend the dwell time by the door opening and closing time plus any added passenger movement time A system approaching achievable capacity could not tolerate such dwell extensions but would in any event be using all doors which might just as well be under driver control avoiding any last minute door opening and closing OTHER STATION CONSTRAINTS Many station related factors can influence demand Poor location inconvenient transfers to connecting modes inadequate or poorly located kiss and ride or park and ride facilities may all deter usage However the only factor that has a potential effect on the achievable capacity of a rail transit line is the rate of
90. e and voltage factors added is 2 L4 D L UE v P B a 1 01G v K 2d a T s a 1 0 1G Xt V lt t ttit 20 000v v Equation 3 11 The equation for moving block signaling systems with a fixed safety separation distance derived from Equation 3 5 of Chapter 2 with dwell and operating margin components removed is T s L S 100 v tiati v K 2d a Equation 3 12 Part 3 RAIL TRANSIT CAPACITY Page 3 54 Chapter 6 Grade Separated Systems Capacity Transit Capacity and Quality of Service Manual Note that this equation is not affected by either line voltage or station grade Lower voltages increase the time for a train to clear a station platform In moving block systems this time does not affect throughput When a train starts to leave a station the target point of the following train is immediately advanced accordingly The worst case approach grade is included in the determination of the safety distance This can result in sub optimal minimum train separation Exhibit 3 44 Minimum Train Separation versus Length 65 60 e 3 aspect R Cab control 14 Moving block VSD 55 50 45 40 35 30 25 Minimum Train Separation s 20 15 180 m 600 ft 150m 500ft 120 m 400 ft 90 m 300 ft 60 m 200 ft Train Length Higher throughput is usually obtained with a moving block signaling system with a variable safety distance co
91. e approximations the number should be rounded down in this case to 3 000 ppphd Part 3 RAIL TRANSIT CAPACITY Page 3 98 Chapter 11 Example Problems Transit Capacity and Quality of Service Manual Example Problem 7 The Situation The above developer is expanding his suburban office Automated guideway transit with development to include a major shopping complex and off line stations recreation facility with an ice hockey arena The Question How can the automated guideway transit be expanded to handle this load The Facts Y Ridership estimates are that the system will handle 25 of the arena s maximum capacity of 24 000 people plus an estimated demand of 1 200 passengers per hour from the shopping complex Y Two adjacent stations serve the sports arena while the shopping center has three stations Y The developer has contracted with the office building tenants to run trains at least every six minutes until midnight each day including weekends and holidays Outline of Solution To handle 24 000 4 1 200 7 200 passengers per hour one solution would be to Longer trains could skip stations operate longer trains with higher occupancy and to omit stops in the office buildings with with too short platforms their short stations The 45 train per hour capacity is no longer practical as heavy loads at the two sports arena stations will extend dwells and longer trains will increase the minimum train separation The capacity is downrated
92. e greatest possible operating margin and recovery time to ensure reasonably even service and to achieve maximum capacity Selecting a recommended operating margin is a dilemma as too much reduces achievable capacity but too little will incur sufficient irregularity that it may also serve to reduce capacity It is recommended that a range be considered for an operating margin A reasonable level for a system with more relaxed loading levels where all of the capacity is not needed should be 35 seconds On systems where headways prohibit such margin a minimum level of 10 seconds can be used with the expectation that headway interference is likely In between these extremes is a tighter range of 15 20 or 25 seconds that is recommended This range is used in estimating achievable capacity in this manual and is recommended as a default value for computations using the complete procedures SKIP STOP OPERATION Skip stop service is used on several of the high capacity rail transit operations in Japan New York and Philadelphia and until recently in Chicago Skip stops provide faster travel times for the majority of passengers with less equipment and fewer staff They do not increase capacity as the constraint remains the dwell time at the maximum load point station at which by definition all trains must stop In fact capacity can be slightly reduced as the extra passengers transferring between A and B trains at common stations can increase dwel
93. e near crush load for North Americans with frequent body contact and inconvenience with packages and brief cases Moving to and from doorways is extremely difficult 7 A lower set back dimension of 0 3 m 12 inches may be used if this permits an additional seat row of seats between doorways Increase to 0 8 m 32 inches for seats behind a bulkhead 9 For more accurate results the sidewall should be divided into the lengths between each set of doors and when appropriate between the door and any articulation and checked or adjusted to ensure that an integer of the seat pitch is used This can be done by dividing the interior free wall length by the number of doorways plus one The number of integer seat pitches in each space is then determined and used to calculate the total vehicle seating However this approach can result in the seating changing radically with a small change in vehicle length articulation length or door width any of which are sufficient to add or remove a row of seats between each set of doors On a four door car with 2 2 seating this results in the seating adjusting up or down by 20 seats at a time five rows of four seats Simple calculations can not substitute for a professional interior layout design that can optimize seating with a combination of transverse and longitudinal seats Other design criteria can also be accommodated including the provision of wheelchair spaces and maximizing circulation space around doorway
94. e of capacity by using the range of loading levels shown in Exhibit 3 55 with peak hour factors of 0 70 to 0 90 Part 3 RAIL TRANSIT CAPACITY Page 3 74 Chapter 7 Light Rail Capacity Transit Capacity and Quality of Service Manual Exhibit 3 55 Recommended Loading Level Range for Light Rail Vehicles in Simple Capacity Calculation N D B Passengers per meter of car length gt c1 oo O0 oc Uo oc Oo o o io 0 3 0 4 Standing Space per square meter NOTE Peak hour factor ranges from 0 7 lower bound to 0 9 upper bound Exhibit 3 56 Light Rail Capacity on Segregated Right of Way With Maximum Cab Control Signaling 22 000 21 000 20 000 19 000 18 000 17 000 16 000 15 000 14 000 13 000 12 000 11 000 10 000 Passengers per peak hour per direction per track 120 90 60 Train Length m NOTE Throughput based on a range of dwell times plus an operating margin of 45 70 seconds Where there are no single track or on street constraints and the signaling system is designed for maximum throughput the maximum capacity can be determined through the procedures of Chapter 6 Grade Separated Systems Capacity summarized for shorter light rail trains in Exhibit 3 56 At the upper end of these levels the system has become a segregated heavy rail transit system using light rail technology No allowance is contained in Exhibit 3 56 f
95. e product of passengers per car and the number of cars adjusted to achievable capacity using a diversity factor to compensate for uneven car loadings over multiple car trains See Exhibit 3 3 Exhibit 3 3 Train Capacity Flow Chart TRAIN CAPACITY Number of PASSENGERS TRAIN PASSENGERS PER NUMBER OF CARS DIVERSITY CAR IN TRAIN FACTOR MAJOR STUDY Limited by MAJOR STUDY DETERMINANT several variants Platform Length LRT street block DETERMINANT train length is main variant Car Size System specific Number of seats Lost space step wells cabs etc Season of year Special event loads Consider treating number and width of doors as of usable train length For simple analysis consider using only train length as surrogate for occupancy i e passengers per metre of length for each mode Loading levels for the calculation of Car capacity is often quoted at the crush loading level but such loading levels are car capacity rarely achieved in practice in the U S and Canada but represent the load for which a car s structure propulsion and braking systems are designed Pass ups define achievable car The only true means of measuring achievable car capacity is on those systems where J capacity pass ups occur That is where passengers wait for the next train rather than crowd onto the one in their station Determining full car capacity and pass
96. e r ec a a ppp ft tt Stopping distance feet Speed mph Exhibit 3 10a Moving Block Headways with 45 Second Dwell and 20 Second Operating Margin Compared with Conventional Fixed Block Systems Headway s 0 10 20 30 40 50 60 Approach speed mph Part 3 RAIL TRANSIT CAPACITY Page 3 102 Appendix A Exhibits in U S Customary Units Transit Capacity and Quality of Service Manual Exhibit 3 24a Linear Passenger Loading Articulated LRVs 3 0 l Ogi iA A A Siemens Duwag 82 ft 2G po articulated 6 Baltimore 95 ft large car Passengers Unit Length ft VIVI V SONRODADWONDA poy LE EL 4E 4 N N e N AR wo Standing Space ft2 p Exhibit 3 25a Linear Passenger Loading Heavy Rail Cars Generic 75 ft car 4 doors longitudinal seating Generic 75 ft car 4 doors 2 2 transverse seating k Generic 75 ft car 3 doors 2 2 transverse seating Chicago 48 ft car 2 doors transverse seating K Vancouver 41 ft car 2 doors mixed seating Passengers Unit Length ft Standing Space ft2 p Exhibit 3 26a Summary of linear passenger loading p ft f Standard Average Median Deviation All Systems 20 18 06 Commuter Rail 1 5 1 4 0 2 Heavy Rail 2 1 1 9 0 6 Heavy Rail less New York 1 7 1 7 0 5 NYCTA alone 2 4 2 4 0 5 Part 3 RAIL TRANSIT CAPACITY Page 3 103 Appendix A Exhibits
97. e tabulated in Chapter 4 Passenger Loading capacity Levels and levels are recommended for use in calculating achievable capacity Station Constraints In rare cases station capacity constraints can reduce achievable capacity by limiting the flow of passengers to the platform and trains Although this manual is concerned with supply rather than demand a section of Chapter 5 Operating Issues discusses these factors Part 3 RAIL TRANSIT CAPACITY Page 3 8 Chapter 1 Rail Capacity Basics Transit Capacity and Quality of Service Manual 2 TRAIN CONTROL AND SIGNALING INTRODUCTION The role of signaling is to safely separate trains from each other and protect specific paths through interlockings at junctions and crossovers Additional functions include automatic train stops should a train run through a stop signal and speed control to protect approaches to junctions sharp curves and approaches to terminal stations where tracks end at a solid wall Rail transit signaling maintains high levels of safety based on brick wall stops and fail safe principles ensuring that no single failure and often multiple failure should allow an unsafe event The rigor with which fail safe principles have been applied to rail transit has resulted in an exceptional safety record However the safety principles do not protect against all possibilities including possible human errors An increasing inability to control the human element responsible for three
98. eeeen nennen eene 3 12 Fixed Block Throughput ssy 4 4o ter heroe eri p d esee 3 12 Station Close In Time eee e e ree HER De A ESEO EEAS 3 12 Moving Block Throughput esee nennen nennen 3 16 Turn Back Throughbput 2 te erect eir three he eR sE 3 18 Junction Througliput eed ee eR eto etse Dee UR ERIS 3 19 Summary e elegit I eii aa eles 3 21 3 STATION DWELL TIMES eeeeeee eren eese ee tenete tns tn atus tn sees su seta sns tn sens enses tuse 3 23 lii P EE Pn 3 23 Dwell Time Components sees rennen enne 3 23 Doorway Flow Rates et metier eR EE EEEE 3 25 Estimating Dwell Times eU emen gehn IIo ir n e e RE 3 27 4 PASSENGER LOADING LEVELS eere eee eese en seen enne ta tne ta sins tn aestu sena 3 29 Introduction n net eer etui re pietre Dto re tee ee Tetris 3 29 Loading Standards acer pee eror aiti i ton 3 29 Space Requirements iie etre tette e etie E ERE HER eee SPD Reb eene entis 3 30 Vehicle Specific Calculations eese 3 31 Default Method tete e OO REDE PR Reste 3 33 Educ 3 33 Loading Diyersity i aee Rn hk ahaa ana 3 35 Part 3 RAIL TRANSIT CAPACITY Page 3 i Contents Transit Capacity and Quality of Service Manual 5 OPERATING ISSUES eese eee eene esent n estatua ons tn tns tn statu ikeen sns en sensn sensa sn sno 3 39 IntrOdUctioh uice tl SEARS ieee eh Se AUR ee Ree 3 39 Operating
99. ene 3 71 Exhibit 3 55 Recommended Loading Level Range for Light Rail Vehicles in Simple Capacity Calculation etre ier eet ete ree Ren 3 75 Exhibit 3 56 Light Rail Capacity on Segregated Right of Way With Maximum Cab Control Signaling inet certet er ih eese i e Pee t eo e rH pite en 3 75 Exhibit 3 57 Commuter Rail Car Capacity sese eren 3 81 Exhibit 3 58 AGT Minimum Train Separation Times eee 3 83 Exhibit 3 59 AGT Train Separation versus Length 3 84 Exhibit 3 60 Suggested AGT Separation Calculation Default Values 3 84 Exhibit 3 61 Orlando Airport People Mover Doorways seen 3 85 Part 3 RAIL TRANSIT CAPACITY Page 3 iv Contents Transit Capacity and Quality of Service Manual 1 RAIL CAPACITY BASICS INTRODUCTION This chapter develops an initial framework to analyze and determine the capacity of rail transit modes in North America Throughout Part 3 capacity analysis is sub divided into two methods The first called the simple method is an easy to use procedure for calculating capacity The second called the complete method adds more variables and is aimed at the experienced user who wishes to review rail transit capacity in alternate scenarios for example changes in seating arrangements or other aspects of interior car design light rail with high or low loading with single track sections with or without traffic signal pre emption etc The procedu
100. er spreadsheet Part 3 RAIL TRANSIT CAPACITY Page 3 52 Chapter 6 Grade Separated Systems Capacity Transit Capacity and Quality of Service Manual When there is uncertainty about these factors fully described in Chapter 3 Station Dwell Times Chapter 4 Passenger Loading Levels and Chapter 5 Operating Issues or where several of the performance variables are unknown for example the technology or specific vehicle has not been selected then following the complete procedure is not recommended The simple procedure provides a generic achievable capacity range with less effort and potentially as much accuracy as the complete method where one or more input factors will have to be estimated Step 1 Determining the Maximum Load Point Station Traditionally the maximum load point station is the principal downtown station or the downtown station where two or more rail transit lines meet However this is not always the case With increasingly dispersed urban travel patterns some rail transit lines do not serve the downtown Los Angeles Green Line and Vancouver s proposed Broadway Lougheed light rail line are examples A regional transportation model will usually produce ridership data by station both Ridership models ons and offs and direction of travel Such data are usually for a two hour peak period or single peak hour and rarely for the preferable 15 minute period Depending on the number of zones and nodes in the model data accura
101. eriod of three decades have resorted to simply assigning a reasonable value to station dwell time Method 1 Assigning a Value Existing rail transit systems operating at or close to capacity have median station dwell times over the peak hour that range from 30 to 50 seconds with occasional exceptional situations such as the heavy peak hour mixed flow at NYCT s Grand Central Station of over 60 seconds A tighter range of dwell time values 35 to 45 seconds is used in the simple procedure and can be used together with the more accurate calculation of the minimum train separation Method 2 Using Existing Dwell Time Data Examples of existing dwell time data from the highest use station on lines that are close to capacity are summarized in Exhibit 3 46 Selection of a dwell time from this table is less arbitrary than Method 1 and allows some selectivity of mode and the opportunity to pick systems and stations with similar characteristics to those of the one under examination The selected median station dwell times range from 27 5 seconds to 61 5 seconds The highest data are mainly alighting and mixed flow records from manually operated systems with two person crews Most station dwell times in Exhibit 3 46 fit into the 35 to 45 second range suggested in the previous method Part 3 RAIL TRANSIT CAPACITY Page 3 57 Chapter 6 Grade Separated Systems Capacity Transit Capacity and Quality of Service Manual Exhibit 3 46 1995 Peak Period
102. erring activity between the subway and streetcars The high volumes of transit vehicles and passengers can cause delays to following streetcars while passengers board and alight from the preceding car Scheduled recovery time for the streetcar operator is hard to accommodate in these conditions as the volume of following cars precludes layover time The Baltimore light rail line also uses single track termini but the level of service 15 minute headway is not high enough for these to be a capacity limitation However the terminals are designed to allow an arriving train to unload passengers before the departing train ahead leaves through the use of an extra platform as shown in Exhibit 3 53 This arrangement allows the location of a station in a relatively narrow right of way since the platforms are not adjacent to each other and a wider center platform is not required Exhibit 3 53 Light Rail Single Track Terminus with Separate Unloading Platform Baltimore 4 gt Arrivals amp Departures Arrivals Only WHEELCHAIR ACCESSIBILITY EFFECTS Introduction The accessibility of light rail transit to wheelchairs and other mobility devices considered together with wheelchairs in this section is a major issue for light rail transit systems The relative rarity of level loading with high level platforms on light rail has resulted in a variety of methods to allow wheelchair access to light rail vehicles Each of the methods is outlined in
103. ete 3 36 Exhibit 3 29 Individual A M Train Loads Vancouver SkyTrain Broadway Station Inbound October 27 1994 50 trains 6 932 passengers in Data Set 3 36 Exhibit 3 30 Diversity of Peak Hour and Peak 15 Minutes sees 3 37 Exhibit 3 31 Observed Rail Headways and Dwell Times sess 3 40 Exhibit 3 32 Dwell and Headway Data Summary of Surveyed North American Heavy Rail Transit Lines Operating at or Close To Capacity 1995 sss 3 41 Exhibit 3 33 Headway Components of Surveyed North American Heavy Rail Transit Lines At or Close to Capacity seconds sseeeeeeee 3 42 Exhibit 3 34 Relationship Between Operating Margin and the Headway Coefficient of MEGEUDMEE T TE 3 43 Exhibit 3 35 Wheelchair Loading Platform and Ramp sees 3 45 Part 3 RAIL TRANSIT CAPACITY Page 3 iii Contents Transit Capacity and Quality of Service Manual Exhibit 3 36 Profiled Light Rail Platform Providing For One Wheelchair Accessible IDE Atavus 3 46 Exhibit 3 37 Profiled Light Rail Platform with Slide Out or Fold Down Step 3 46 Exhibit 3 38 Grade Separated Rail Transit Performance Assumptions Simple Method Capacity Calculation 5 e peteret pter diete 3 49 Exhibit 3 39 Cab Control Throughput esee 3 50 Exhibit 3 40 Moving Block Variable Safety Distance Throughput
104. exiting from a platform Adequate passageways stairways and escalators must be provided to ensure that a platform can clear before the arrival of the next train Inadequacies in passenger access to a station may reduce demand but not capacity Station exiting requirements are specified by the U S National Fire Prevention Association rapid transit standards 130 Exits emergency exits and places of refuge must be adequate to allow a platform with one headway s worth of passengers plus the entire complement of a full length fully loaded train to be able to be evacuated to a safe location within four minutes without using elevators and treating escalators as a single width stairway These regulations ensure that in all but the most unusual circumstances where there is a disproportionate reliance on emergency exits full capacity loads can leave the platform before the next train arrives On older systems NFPA 130 requirements may not be met Additional exits must be provided to ensure that achievable capacity is not constrained by platform back ups Rates of flow are established for passageways and up and down stairs and escalators according to width In emergencies exit fare payment devices can be placed in a free passage mode This is not the case in normal operation when adequate exit fare control checks must be provided on those systems with distance related fares Part 3 RAIL TRANSIT CAPACITY Page 3 44 Chapter 5 Operating Issues Tra
105. f an exclusive light rail transit lane where street running with long trains occurs Indeed as a result of this concern operation with mixed traffic is very rare on new light rail transit systems Where buses and light rail transit trains operate alongside each other on transit malls in Baltimore and Calgary the rail stations bus stops and lanes are laid out to cause a minimum of interference between the modes Station Limitations An obvious limitation to train length is the length of station platforms For most light rail transit routes this is not a problem as stations have been built with current ridership and service levels in mind The relative importance of this constraint is much greater for commuter rail where platform length is often constrained for historical reasons A more important restriction can be in the design of terminal stations Toronto s streetcars face such terminal design problems where two or more routes share a common terminal and single track turning loop This is the case at the Broadview and Dundas Avoiding premature activation of crossing gates and signals Train to wayside communication Exclusive lanes can mitigate street block length constraints Platform length Terminal station design Part 3 RAIL TRANSIT CAPACITY Page 3 69 Chapter 7 Light Rail Capacity Transit Capacity and Quality of Service Manual Wheelchair boarding and alighting times West subway stations where there is heavy transf
106. f time particularly to contain a schedule recovery allowance many systems maintain such close headways with minimal delays 5 While side platforms reduce the track to track centers and so reduce the maneuver time they require passengers to be directed to the correct platform for the next departing train This is inherently undesirable and becomes more so when a train cannot depart due to a defect or incident and passengers must be redirected to the other platform Part 3 RAIL TRANSIT CAPACITY Page 3 18 Chapter 2 Train Control and Signaling Transit Capacity and Quality of Service Manual This analysis assumes that any speed restrictions in the terminal approach and exit are below the speed a train would reach in the calculated movements approximately 21 km h 34 mph on a stop to stop approach and 29 km h 47 mph as the end of the train leaves the interlocking on exit Normally there would be no restrictions so low but following London Transport s Moorgate disaster when a fully loaded train accelerated into the wall at the end of a terminal station some systems have imposed low entry speeds occasionally enforced with speed control signaling This maximum permitted terminal time can be calculated for the specific system and terminal parameters Where the time is insufficient there are numerous corrective possibilities These include moving the cross over as close to the platform as possible however note that structures can restrict
107. g the methods for grade separated rail transit given in Chapter 6 However allowances for any speed restrictions due to grade crossings must be made Where full signal pre emption is not available the procedures of Part 2 for street running should be used to determine line capacity since it incorporates the cycle length of traffic signals pre empted or not Signal Pre emption Light rail transit lines operating on private right of way are generally given full priority at grade crossings by railroad type crossbucks bells and gates or by traffic signal pre emption Gated railroad style crossings are used where train and or traffic speeds are high Railway type gated crossings consistently have the longest phase lengths of the three main crossing devices Crossbucks and bells alone or pre empted traffic signals are used where speeds are lower Delays to other traffic are reduced when gates are not used since the time taken for gates to be lowered and raised around 30 seconds is removed as a factor The potential delay to cross traffic at crossings with traditional railroad protection is almost three times longer than with 100 pre empted signalized intersections At higher train frequencies these occupancy times will become unacceptable and signalized intersections would be required potentially reducing light rail speeds but not the light rail capacity as the crossing occupancy time is well within a normal green phase Grade Crossings an
108. gency plans to build its tracks 5 m apart and use 10 switches with a throw to lock time of 6 seconds at main line junctions To make operations through a flat junction reliable the agency plans to increase the operating margin to 45 seconds hence the headway increase from 100 to 120 seconds Outline of Solution Solving this problem requires use of Equation 3 8 from Chapter 2 Steps Equation 3 8 is 2 T 2 HOBO ac pay a a d The variables used are summarized in the following table Substituting the known variables into the equation produces H j 32 4421 34 10 7 6 0 45 H j 115 4 seconds While the resulting value of H j would appear to support two minute headways it is only about four seconds less than the planned headway Based on this narrow margin it would be prudent to opt for a flying junction rather than risk service disruptions with a flat junction even with the operating margin increased to 45 seconds This is consistent with recommendations in Chapter 2 that junctions where headways are below 3 minutes should be grade separated Value Term Description calculated H j limiting headway at junction seconds 32 4 seconds H I line headway from Example 1 b 200 m T train length meters 9 62 C switch angle factor 9 62 for a 10 switch 5m S track separation meters 1 8 m s ag initial service acceleration rate m s 1 8 m s ds service deceleration rate m s
109. gitudinal seating with a range of 7 0 to 11 5 passengers per meter of car length 2 1 3 5 p ft of car length The higher end of this range approaches that of crush loaded conditions The lower end of the range at 7 to 8 passengers per meter length 2 1 2 4 p ft length with a standing space per passenger of 0 4 to 0 3 m 4 3 to 3 2 ft is an appropriate and tight range for higher use systems A lower figure of six corresponds closely with the recommended quality loading of an average of 0 5 m 5 4 ft per passenger and is appropriate for a higher level of service on new systems In either case a reduction by one should be used for smaller narrower cars Exhibit 3 25 Linear Passenger Loading Heavy Rail Cars Generic 23 m car 4 doors longitudinal seating Generic 23 m car 4 doors 242 transverse seating k Generic 23 m car 3 doors 242 transverse seating gt lt Chicago 14 6 m car 2 doors transverse seating K Vancouver 12 5 m car 2 doors mixed seating Passengers Unit Length m Standing Space m2 p Exhibit 3 26 summarizes the average loading level in passengers per unit length for typical North American rail transit cars Exhibit 3 26 Summary of Linear Passenger Loading p m pM m Standard Average Median Deviation All Systems 6
110. han in others e namulti car train some cars carry more passengers on average than others e Many factors reduce train performance propulsion faults or differences door problems operator variation which may not only increase the sustainable average headway but will increase the variation in headway and consequently the passenger load waiting for that train e Minimum headway by definition leaves no margin for schedule recovery from even minor delays leaving the system susceptible to more variation in service e Passenger demand is unevenly distributed within the peak period there may be predictable waves of demand corresponding to specific work start and finish times The capacity rate requirement for the peak 10 to 15 minutes may have to be higher than the average for the peak one or two hours e There is day to day fluctuation in demand Some may be associated with the day of the week peaks have become lighter on Mondays and Fridays as more people move into shorter or flexible work weeks seasonally lighter in the summer and at Christmas time weather and special events e Passengers are resilient to a degree and will tolerate overcrowding or delay on occasion This permits systems at capacity to accommodate special events or recover from service delays Achievable capacity is the product of the design maximum capacity and a series of reality factors which adjust the ideal capacity These factors are not absol
111. he agency s capacity needs the hourly capacity of the line using each car type must be determined This procedure is simplified in this example by the agency s ability to schedule trains to meet the peak 15 minute demand avoiding the need to consider the temporal distribution of travel The capacity that can be provided with each car type should be considered independently hourly capacity passengers per car x cars per train x trains per hour a Single level cars The effective capacity per car is 9096 of 120 or 108 passengers An eight car train of single level cars could thus carry 864 passengers With six trains per hour the capacity is 5 184 passengers per hour b Two level cars The effective capacity per car is 9096 of 180 or 162 passengers An eight car train of two level cars could thus carry 1 296 passengers With six trains per hour the capacity is 7 776 passengers per hour Since eight car trains of single level cars are unable to handle the predicted demand it Double deck cars needed to appears that the agency should plan on ordering two level cars for use on this route The handle capacity calculation above shows that the two level cars can accommodate the projected demand with some room for ridership growth The only alternative to purchasing the two level cars would be to operate longer trains Longer trains that overhang and assign passengers to cars according to their destination station since not all cars platfo
112. ht rail capacity teething problems Most low floor designs are intended for city streetcar or tramway applications and do not have the top speeds nor ride quality suitable for North American light rail operations and track standards These restrictions can be overcome or reduced by hybrid or partial low floor cars with up to 7096 of the floor at the low height This design results in a lower cost higher top speed and better ride quality on open track The ends of the car and the driving end trucks can be of conventional construction and can retain component and maintenance commonality with conventional high floor light rail equipment Steps inside the car provide access to the high floor sections 10096 low floor designs require the use of stub axles hub motors and other space saving components These items add to costs and have not yet been satisfactorily proven for high speed use or on the lower quality of tracks typical of North America when compared to Western Europe As a result the cars purchased for Portland and Boston are of the partial low floor type Despite high costs and technical challenges the substantial benefits of low floor cars have made them a popular choice in Europe Many European light rail systems have extensive on street operation and recent new vehicle procurements have been predominantly low floor Manufacturers are rationalizing production to fewer modular designs Vehicles designed for on street operation still rem
113. ide from the need for a second stop is very efficient with the time required for a passenger movement being as low as 10 seconds Two of the major surface stops on the Muni system have been converted entirely to high platforms with proof of payment fare collection to speed general passenger flows with the additional benefit of making wheelchair loading and unloading easier Where no high or mini high platforms exist the Muni light rail system is not accessible to wheelchairs Pittsburgh s PAT light rail lines are only available to wheelchairs at high platform stations Street level stops as in San Francisco are not accessible Low Floor Cars Low floor cars2 offer a straightforward solution to the need for universal access to light rail vehicles By bringing the floor height down to just above the railhead boarding is simplified for all passengers as steps are no longer required Small extendible ramps and slight increases in platform edge height allow passengers in wheelchairs and other mobility devices to board without the aid of lifts or special platforms Low floor cars provide much of the benefit of level loading without the need for high platforms Typical floor height is 350 mm 14 inches about double the height of a normal curb Medium or intermediate height platforms are therefore still required for no step boarding Bridge plates and the assistance of train operating staff are still required on most designs although it appears
114. ided by high or low loading and by the method of handling wheelchairs Train Control Throughput The number of trains per hour that is theoretically possible is dependent on the particular signaling systems including e conventional block signaling e block signaling with short blocks overlapping blocks or ghost overlays to decrease headways and e communication or transmission based signaling systems with moving blocks Chapter 2 Train Control and Signaling describes different signaling systems and develops empirical methods to estimate their throughput More precise throughput determination requires the use of computer simulations Line capacity definition Line capacity is determined by the train control system and station dwell times Part 3 RAIL TRANSIT CAPACITY Page 3 5 Chapter 1 Rail Capacity Basics Transit Capacity and Quality of Service Manual Specific factors affecting throughput of commuter rail trains Operational allowances and controlling dwell times Commuter rail dwells are often relatively independent of passenger flows Commuter Rail Throughput Certain line capacity issues are specific to commuter rail operation Commuter rail signaling generally is of standard railroad operation and must accommodate trains of different lengths and speeds Contract operations may set limits on the number of trains per hour See Chapter 8 for specifics Station Dwells Station dwells and train control system
115. ime is spent waiting for the progression to start at each station The progression is frequently made part of the normal traffic signal phasing and so is fully integrated with signaling for automobiles on cross streets This reduces delays for transit and car drivers alike Station stops are accommodated by the train missing one signal cycle and proceeding on the next Ideally the signal cycle length will be slightly longer than a long average dwell time in order to allow the majority of trains to leave shortly after passenger boardings and alightings have ended Part 3 RAIL TRANSIT CAPACITY Page 3 66 Chapter 7 Light Rail Capacity Transit Capacity and Quality of Service Manual It is useful if the train operator waiting at the first signal in a series of signals can determine when the green window will start as this allows the operator to serve more passengers by maximizing the dwell time at the station In this way the train operator only closes the doors when he knows that the train will soon be able to proceed In some cases this can be done by observing the operation of the other traffic signal phases However this may not be possible at some locations and in these cases a special signal display can be added that counts down the time to the start of the light rail phase Such countdown timers are used at a number of locations on the downtown portion of the San Diego Trolley Operating heritage streetcars vintage trolleys in conjunction
116. ion 1 5 seconds tbr brake system and operator reaction time 1 3 m s as initial service acceleration rate 1 3 m s ds service deceleration rate 6 25 meters Pe positioning error moving block only L 28 Note that these station approach speeds are the optimal speeds to achieve minimum train separation Solving for the optimal approach speed directly is not a simple task and is best done using a computer spreadsheet s solver or goal seek function to automate the iterative process that is required Part 3 RAIL TRANSIT CAPACITY Page 3 90 Chapter 11 Example Problems Transit Capacity and Quality of Service Manual Steps a with cab control signaling The relevant equation is Equation 3 4 modified to remove dwell and operating margin 2 T s 2 L D i L i 100 B Va n ati 1 V es a v K 2d 2v V ax d Substituting the known variables into the equation produces T s 18 0 13 9 2 53 5 54 0 406 0 507 3 0 0 5 1 5 T s 51 1 seconds b with moving block signaling ose e ve y K 2d a 1 01G I r 4 al DL h v v OS 20 000v s J t t max Substituting the known variables into the equation produces T s 13 5 2 33 5 88 0 382 0 550 3 0 0 5 0 T s 30 9 seconds The net result is that the minimum train separation at stations negating the effects of station dwells and an operating margin would be 51 1 seconds with a cab control system or 3
117. ion the standard variation deviation divided by the mean There could be expected to be a relationship between operating margin and service reliability however Exhibit 3 34 shows no such relationship Some inference can be drawn in that the system with the best headway adherence SkyTrain in Vancouver British Columbia also has the most generous operating margins Part 3 RAIL TRANSIT CAPACITY Page 3 42 Chapter 5 Operating Issues Transit Capacity and Quality of Service Manual Exhibit 3 34 Relationship Between Operating Margin and the Headway Coefficient of Variation 80 Te T T i i i Vie ene mm Me eee mne dne 4 e i i i M tetera rete fos E i i I O i i po r o i l i SG l l z i I i pb psteccteet esee estes oieege peescsesescet pesesesesesern E 30 Joanne i Ian ee o i f f i OG EE uce es tois cce fees tee sme Do Sot ores oeste s 6 Sis its tet aii iva airs TOSS eee ee ne ne tees spe Dees eae ps Sa ee i i i 0 I I I 0 1 0 2 0 3 0 4 0 5 Headway Coefficient of Variation ESTIMATING MARGINS Although there is no clear relationship between existing rail transit operating margins and other operating criteria this important factor and the related terminal recovery or lay over time cannot be discounted The inevitable headway irregularities and the need for reasonable operating flexibility require th
118. ivity center Although most automated guideway transit is a sub set of the main category Grade Separated Rail with very short trains the use of off line stations on certain systems is unique to this mode and requires separate examination Off line stations can also increase the capacity of more conventional rail transit as discussed in Chapter 5 Operating Issues Each of these categories is provided with its own section with procedures for determining capacity Chapter 6 Grade Separated Rail Capacity Chapter 7 Light Rail Capacity Chapter 8 Commuter Rail Capacity and Chapter 9 Automated Guideway Transit Capacity The minor exceptions where there are grade crossings on rail rapid transit CTA will be discounted Routes with more than two tracks will be discussed relative to express local and skip stop service However it is not intended to otherwise develop unique capacity calculations for multiple track routes The Morgantown automated guideway transit the only North American example of AGT with off line stations is not classed as a public operation by APTA Part 3 has been condensed from TCRP Report 13 Rail Transit Capacity Exhibits appearing in Appendix A are indicated by a marginal note such as this Fully segregated electric multiple unit rail Light rail without full segregation Commuter rail without full segregation Automated guideway transit Part 3 RAIL TRANSIT CAPACITY Page 3 1 Chapter 1 Rail
119. l adjustments unnecessary Cars intended for higher density loading should have a greater number of doors Space inefficiencies at the extremities of a car are unavoidable unless the London Transport Underground arrangement of doors at the very end of each car is adopted The above process can be expressed mathematically as v L 05DW D i 2 L L D 25 sp sp w Equation 3 9 where V vehicle capacity peak 15 minutes E vehicle interior length m or ft L articulation length for light rail m or ft W stepwell width certain light rail only m or ft W vehicle interior width m or ft Ssp space per standing passenger m or ft 0 2 m 2 15 ft maximum 0 3 m 3 2 ft reasonable and 0 4 m 4 3 ft comfortable N seating arrangement 2 for longitudinal seating 3 for 2 1 transverse seating 4 for 2 2 transverse seating and 5 for 243 transverse seating Sa area of single seat m or ft 0 5 m 5 4 ft for transverse and 4 3 ft 0 4 m for longitudinal D number of doorways doorway width ft or m S z l 10 This upper level is a peak 15 minute occupancy level for standing passengers Over the peak hour it corresponds closely to Pushkarev and Jacobs estimates of a United States rush hour loading average of 0 5 m 5 4 ft per passenger both seated and standing It also corresponds to Pushkarev and Batelle s recommendation for an a
120. l times Skip stop operation is only applicable if the headways are sufficiently short that the up to two headway wait at minor stations is acceptable to passengers Part 3 RAIL TRANSIT CAPACITY Page 3 43 Suggested operating margin range Skip stop operation increases speed but not capacity Chapter 5 Operating Issues Transit Capacity and Quality of Service Manual Advantages of on demand light rail stops Door cycle times Inadequate platform exit capacity can reduce capacity The common stations on the Japanese skip stop operations have multiple platforms typically two island platforms allowing passengers to transfer across the platform between A and B or between local and express trains Light rail operations may also skip stations when an on demand operating policy is adopted This requires that an on board passenger signal to stop the train Drivers must observe whether there are any waiting passengers as they approach each station This is a particularly efficient way to increase line schedule speed and reduce operating costs However at higher capacity levels all trains will stop at all stations and so the practice has no effect on achievable capacity Demand stops are rare on new North American light rail systems even where there are clearly some low volume stations where during off peak times on demand stops could contribute to lower energy consumption lower maintenance costs and a faster more attractive servic
121. l trains share trackage or where the signaling system is designed solely for freight with long signal blocks Additional complications are raised by the variety of services operated and the number of tracks available The busier commuter rail lines tend to offer a substantial number of stopping patterns in order to minimize passenger travel times and maximize equipment utilization A common practice is to divide the line into zones with trains serving the stations in a zone and then running express to the station s in the central business district Through local trains provide connections between the zones A number of lines in the Chicago and New York areas are operated this way Metra s Burlington Northern line to Aurora operates with five zones in the morning peak Metro North s New Haven line including the New Canaan Branch operates with seven zones Such operating practices are made possible with three or more tracks over much of the route and the generous provision of interlockings to allow switching between tracks Grade separated junctions are also common where busy lines cross or converge The capacity of this type of operation is hard to generalize and should be considered on a case by case basis Such heavy operations are similar to grade separated rapid transit in many ways but with some notable exceptions such as the wide range of services operated Station Constraints Another principal difference between commuter rail and the othe
122. les in Simple Capacity Calculation 2 50 2 25 2 00 1 75 1 50 1 25 Passengers per foot of car length 1 00 2 1 3 2 4 3 Standing Space per square foot NOTE Loading diversity factor ranges from 0 7 lower bound to 0 9 upper bound Part 3 RAIL TRANSIT CAPACITY Page 3 105 Appendix A Exhibits in U S Customary Units Transit Capacity and Quality of Service Manual Exhibit 3 56a Light Rail Capacity on Segregated Right of Way With Maximum Cab Control Signaling 22 000 21 000 20 000 19 000 18 000 17 000 16 000 15 000 14 000 13 000 12 000 11 000 10 000 direction per track Passengers per peak hour per 400 300 200 Train Length ft NOTE Throughput based on a range of dwell times plus an operating margin of 45 70 seconds Exhibit 3 60a Suggested AGT Separation Calculation Default Values Term Unit Description Heavy Rail AGT Pe ft positioning error 20 20 L ft length of the longest train 660 165 D ft distance from front of train to exit block 35 0 K service braking rate 75 75 B train detection uncertainty constant 2 4 4 fixed block B train detection uncertainty constant 1 1 moving block tos S time for overspeed governor to operate 3 1 tjl S time lost to braking jerk limitation 0 5 0 5 ds ft s service acceleration ra
123. ls dwell 45 seconds operating margin 20 seconds Part 3 RAIL TRANSIT CAPACITY Page 3 15 Chapter 2 Train Control and Signaling Transit Capacity and Quality of Service Manual Exhibit 3 9 Headway Changes with Voltage 124 z 122 ks c o o o e gt 120 G z o oj 2 118 116 100 95 90 85 80 75 70 of line voltage Moving Block Throughput Moving block signaling systems replace separation by fixed blocks with a moving Moving block train separation safety distances block based on the braking distance to a target point plus a safety separation distance The can be fixed or variable safety separation distance can be fixed for a given system and type of rolling stock or can be continually adjusted with speed and grades Equation 3 5 determines the station headway for a moving block signaling system with fixed safety separation Note that the time for the overspeed governor to operate is incorporated into the safety distance and so does not appear in the equation LS 100 v H s K 2 tty thy tty i Equation 3 5 where typical values shown in square brackets H s station headway s L length of the longest train 200 m or 660 feet Va station approach speed m s K braking safety factor 75 ti time lost to braking jerk limitation s 0 5 s thy operator and brake system reaction time s 1 5 s ta dwell time s 45 s see also Chapter 2 Lm operating margin s 20 s see also
124. ly the agreement will ensure a minimum number of commuter rail trips per hour These may be uni directional that is all trains must platoon in one direction in each peak period This is generally not a capacity problem but rather an efficiency issue with respect to equipment and staff utilization Uni directional operation is an issue on lines where reverse commuting to suburban work sites is important For example Chicago s Metra is planning new services aimed specifically at the growing reverse commuter market The number of commuter rail trips available per hour may range from one upwards into the double digits Ten or more trains per hour is at the upper range of traditional railroad signaling and will exceed it if long slow freights must be accommodated At the upper end of this range commuter rail is effectively in sole occupancy of the line for the peak period and is approaching levels where the capacity calculations of Chapter 6 Grade Separated Systems Capacity should be considered Only in this case can the train separation equation be used as a rough approximation of railroad signaling throughput by using suitably lower braking and acceleration rates longer train length and adjusting the separation safety factor B from the suggested value of 2 4 for a rapid transit three aspect signaling system to 3 or 4 This equation and the associated equation for junction throughput do not apply in locations and times where freight and commuter rai
125. m Hybrid or overlay systems are available that allow use by unequipped trains with longer separation while still obtaining the close headway of the moving block system for the urban or short distance trains AUTOMATIC TRAIN OPERATION Automatic acceleration has long been a feature of rail transit where relays and more recently microprocessors control the rate of acceleration smoothly from the initial start to maximum speed Linking this feature to on board commands from the signaling system provides automatic train operation The driver or attendant s role is typically limited to closing the doors pressing a train start button and observing the line ahead with limited manual operating capabilities to deal with certain failures Dispensing entirely with a driver or attendant is controversial but has demonstrated its economy and safety on numerous Automated Guideway Transit AGT systems and on rail transit systems in Europe and Vancouver B C Automatic train operation ATO with or without attendants or drivers allows a train to more closely follow the optimum speed envelope and commence braking for the final station approach at the last possible moment This reduces station to station travel times and more importantly from the point of capacity it minimizes the critical station close in time the time from when one train starts to leave a station until the following train is berthed in that station This can increase total line capa
126. m a stop traverse the cross over and be fully berthed in the station before the next exiting train lower right can leave The exiting train must then clear the cross over and the interlocking switches must be reset before another train can enter the station The minimum time for a train to unload and load passengers and for the driver to change ends inspect the train and check train integrity and braking allowing for the two berths is shown in Equation 3 7 2 P T CS E P T CS t 2 H t a t d 2a Equation 3 7 where typical values shown in square brackets t terminal layover time s H train headway 120 seconds te switch throw and lock time 6 seconds P platform length 200 meters or 660 feet T distance from cross over to platform 20 meters or 65 feet S track separation platform width 1 6 m 5 25 feet 10 meters or 33 feet C switch angle factor 5 77 for 6 switch 6 41 for 8 switch and 9 62 for 10 switch d initial service acceleration rate 1 3 m s or 4 3 fiss d service deceleration rate 1 3 m s or 4 3 fus A typical terminal layover time can then be calculated using the typical parameters in the square brackets above including a headway of 120 seconds The terminal time f is less than or equal to 175 seconds per track This would increase by 9 seconds if the incoming train did not stop before traversing the cross over While this is not a generous amount o
127. m speed reached 50 km h 13 9 m s ds deceleration rate 1 3 m s lj jerk limiting time 0 5 s tor operator and braking system reaction time 1 5 s SM speed margin constant 1 1 lom operating margin 20 s The resultant time to cover the single track section is 183 1 seconds The minimum headway on a single track section is twice this time 366 2 seconds plus approximately six seconds for the switch to throw The total should be rounded up from 6 minutes 12 seconds to the nearest even hourly headway of 71 2 minutes If the light rail line has significant on street operating segments it is unlikely that service can be maintained with sufficient regularity that trains will not be held up at the entrance to the single track section waiting for the opposing train to clear In this case it is prudent to increase the minimum headway to the next even interval trains every 10 minutes In the event of track maintenance or an emergency such as a traffic accident failed light rail train or derailment crossovers are usually provided to permit single track working around the obstruction For long term obstructions such as a track renewal program temporary crossovers called shoo flys can be used Where there is a signaling system this is only possible if the signaling system is equipped for two way operation on either track or by reverted to a slower manual line of sight operation Such emergency operation is then limite
128. mprised of the braking distance at the particular speed plus a runaway propulsion allowance The equation for such a system derived from Equation 3 6 of Chapter 2 with dwell and operating margin components removed and a line voltage factor added is L P T s hs 209 B ve v K 2d a 0 01G IS v 20 000v a Jr Rit max y Equation 3 13 The appropriate equation must be solved for the minimum value of 7 s The approach speed v that produces this minimum value must then be checked against any speed restrictions approaching the station from Exhibit 3 45 Part 3 RAIL TRANSIT CAPACITY Page 3 55 Chapter 6 Grade Separated Systems Capacity Transit Capacity and Quality of Service Manual An alternative version of this figure in U S customary units appears in Appendix A Exhibit 3 45 Distance Speed Braking Into a Station 300 250 200 150 100 Stopping distance m 50 Speed km h The dotted line example in Exhibit 3 45 shows that at 120 meters 400 feet from a station the approaching train will have a speed of 65 km h 40 mph If there is a speed limit at this point that is lower than 65 km h 40 mph then the minimum train separation T s must be calculated with the approach speed v set to that limit Finally check the results with Exhibit 3 44 The minimum train separation should be close to or moderately greater than the values charted If lower there is probably an error as the cha
129. n this section The first method is the one used in the simple procedure of this chapter and by 14 Distance from the front of the approaching train to the stopping point 15 See Reference 1 No operating margin should be added when controlling dwell is calculated Part 3 RAIL TRANSIT CAPACITY Page 3 56 Chapter 6 Grade Separated Systems Capacity Transit Capacity and Quality of Service Manual Four methods of estimating most of the literature references simply assigning a reasonable figure to the headway Controlling dwell critical station The second method uses field data from this study allowing the selection of a controlling dwell time from the headway critical station of rail transit lines with similarities to the one being analyzed These two methods are suitable where information on passenger flows at the headway critical station is not available The third method is only suitable for new lines in cities with existing rail transit systems Here the method outlined in Chapter 3 of using the mean dwell time plus 2 standard deviations based on a comparable station on the existing network is suggested The fourth and final method uses the statistical approach of Chapter 4 of determining station dwell times based on peak hour passenger flows This method is complex and still requires an estimate of the ratio of the busiest door to average door flow None of these methods are entirely satisfactory This explains why practitioners over a p
130. ncluding Los Angeles St Louis and Calgary The use of high platforms on the transit mall portion of Calgary s light rail lines illustrates the difficulty accommodating this preferred loading method in on street locations Part 3 RAIL TRANSIT CAPACITY Page 3 71 Chapter 7 Light Rail Capacity Transit Capacity and Quality of Service Manual Mixed use of high and low platforms Dwell times with car mounted lifts Dwell times with wayside lifts High level platforms at stations are also used in Buffalo Pittsburgh and San Francisco in combination with low level loading at other stops Buffalo is unusual in that a subway with high level platforms serves the outer portion of the line while the downtown segment is on a transit mall with low level loading using fold out steps and mini high platforms discussed below for wheelchair access Pittsburgh has separate doors for each platform level while the San Francisco Muni uses cars fitted with steps which can be mechanically raised to floor height at high platform stations Car Mounted Lifts Car mounted lifts are used only on the San Diego Trolley one of the first light rail transit systems to be wheelchair accessible Lifts are mounted in the cars so that the first door on the right side of every train is lift equipped When not in use the lift is stored in a vertical position which blocks the doorway from use by other passengers While the lift model used initially was prone to failure
131. nd headways can exceed maximum loading levels to be followed by a number of under utilized trains Doorway flow rates on AGT AGT headways AGT loading levels tend to be atypical of transit overall Part 3 RAIL TRANSIT CAPACITY Page 3 85 Chapter 9 Automated Guideway Transit Capacity Transit Capacity and Quality of Service Manual Off line stations increase capacity At the other extreme are the narrow all seated configuration amusement park monorails with loading as low as 2 3 passengers per meter of train length 0 6 0 9 p ft of length The peak hour factor on the latter type systems attains unity when arrangements and continual passenger line ups ensure that every seat on every train is occupied in some cases through all hours of operation The hourly achievable capacity of non public transit AGT systems requires consultation with the system supplier The methodologies and calculations of this report should only be used as a last resort and then treated as a guideline OFF LINE STATIONS Off line stations maximize system capacity They are used on several rail transit lines in Japan to achieve some of the highest throughput for two track rapid transit lines in the world In North America they are the exclusive preserve of the automated guideway transit line in Morgantown West Virginia 2 Off line stations permit a train throughput that is partly independent of station dwell time Throughput is that of the train
132. ng reaches maximum capacity then 25 seconds should be used Step 5 Selecting a Passenger Loading Level Chapter 4 Passenger Loading Levels discusses the wide range of loading levels used in North America Selecting a loading level is a policy issue and the process for the complete procedure is the same as that of the simple procedure Use of the passenger occupancy per unit length of train is recommended In selecting a loading level take into account that this is for the 15 minute peak period and that the average over the peak hour will be more relaxed If the line for which capacity is being determined is an addition to an existing system then existing occupancy levels or where available existing loading policies can be used Some cities have a wide variation of peak 15 minute loading levels from line to line Where this variety exists then the loading level should be selected based on the closest matching line for example a heavy trunk serving downtown or a cross town feeder line Exhibit 3 24 and Exhibit 3 25 provide a range of loading levels from 5 to 9 passengers per meter of car length 1 5 2 7 p ft of length for light rail and from 7 to 11 2 1 3 4 p ft of length for heavy rail For new systems where attempts are being made to offer a higher quality of service the recommended approach is to base the loading level on the commonly suggested medium comfort level for new rail transit systems of 0 5 m 5 4 ft per passenger aver
133. ng to build more expensive off line stations and purchase addition rolling transit stock for a sports arena demand that only occurs a few days a year It is more likely that the system would be designed for maximum office and shopping complex demands When a sports event takes place the automated guideway transit system would be filled to capacity and the overload handled by transit authority buses of which there is a surplus at the off peak hours typical of sport event starts and finishes Part 3 RAIL TRANSIT CAPACITY Page 3 99 Chapter 11 Example Problems Transit Capacity and Quality of Service Manual This page intentionally blank Part 3 RAIL TRANSIT CAPACITY Page 3 100 Chapter 11 Example Problems Transit Capacity and Quality of Service Manual APPENDIX A EXHIBITS IN U S CUSTOMARY UNITS Exhibit 3 5a Station Headway for Lines at Capacity 170 160 150 140 Headway s 130 120 EJ TT 39 110 0 10 2 0 40 50 60 Approach speed mph RN Er 0 3 Exhibit 3 6a Speed Limits on Curves and Switches Speed limit mph nim Ea L a EE E Ea Z A 4 AT EXT EE 0 50 100 150 200 250 300 350 400 450 500 550 600 Curve radius feet Part 3 RAIL TRANSIT CAPACITY Page 3 101 Appendix A Exhibits in U S Customary Units Transit Capacity and Quality of Service Manual Exhibit 3 7a Distance Speed Chart Exe esses eS MC ON DN CUN ae CD CILE SIL I JM ese a
134. ni such that passing locations are not close to the single track sections Where there is more than one single track section this can become difficult but not impossible Lengthy single track sections can severely limit headways and capacity and may require one or more double track passing sections in the single track section These should wherever possible be of sufficient length to allow opposing trains to pass on the fly and to allow some margin for off schedule trains Obviously trains should be scheduled to pass at this location An alternative version of this figure in U S customary units appears in Appendix A To estimate best headway multiply single track time by two and add an operating margin Scheduling for single track Passing sections Part 3 RAIL TRANSIT CAPACITY Page 3 65 Chapter 7 Light Rail Capacity Transit Capacity and Quality of Service Manual Economic signaling constraints On street capacity Reserved lanes for light rail vehicles and streetcars Calculating on street train throughput Signal pre emption Signal progression SIGNALED SECTIONS Restrictions due to signaled sections are largely covered in Chapter 6 Grade Separated Systems Capacity However it should be realized that many light rail lines are not signaled with the minimum possible headway in mind but more economically for the minimum planned headway This can easily make signaled sections the capacity constraint In this
135. nlike the grade separated rail capacity determination there are no reasonable methodologies that allow the calculation of the train control throughput and controlling station dwell times to produce the achievable passenger capacity of a line The number of trains that can be operated in the peak hour is dependent on negotiations with the owning railroad Many factors are involved single or double or more track the signaling or train control system grade crossings speed limits freight service switching services and the priorities to be accorded to these Although railroads are becoming more conducive to accommodating commuter rail services and the revenue and capital upgrading they produce they have the upper hand and obtaining paths for commuter trains at a reasonable cost can require difficult and protracted negotiations There are an increasing number of exceptions where the operating agency has purchased trackage and or operating rights and so has more or total say in the operation and the priority of passengers over freight The two New York carriers own the great majority of track they operate on while New Jersey Transit SEPTA the MBTA Metra and Los Angeles Metrolink among others own substantial portions of the trackage they use Some agencies such as SEPTA have leverage with the freight railroads as they own track used by the freight carriers as well as the reverse However there may still be strict limits on the number of t
136. nsit Capacity and Quality of Service Manual The nominal passenger handling rate for a single coin or magnetic ticket actuated fare gate or turnstile is 60 passengers per minute This is optimistic Actual usage will range between 30 and 40 passengers per minute possibly longer at stations with a large proportion of tourists or other non regular transit users The exit fare gate rate is also reduced by periodic failures and on systems with distance related fares by tickets with inadequate stored value Typically 1096 of fare gates should be assumed to be out of service at any time About one in four thousand transactions will fail with magnetic tickets Proximity cards are reported to have failure rates two to three times better but there is insufficient use to confirm this Add fare requirements can be as low as one in a hundred depending on operator policy several systems allow a passenger to underpay on the final ride on higher value stored value tickets as a form of random discount Whether due to a failure to read a ticket or the need to add fare to a card the exiting fare gate can be obstructed for a considerable period particularly if the passenger repeats the ticket insertion It is essential that adequate exiting fare equipment be provided at high capacity stations to ensure that passenger queues do not back up onto a platform Fare payment is a particular factor on the few light rail systems that still use on board payment and checks
137. ntral New York NB 53 9 14 8 184 1 29 3 53 0 47 5 PATH Exchange Place Newark ERA 233 7 4 1158 20 1 55 0 22 6 PATH Journal Square We WELT 473 234 1997 237 55 0 50 6 SkyTrain Broadwa eG aoe 302 26 1456 207 40 0 70 2 SkyTrain Burrard VEM ME WB 26 7 2 5 1507 177 40 0 79 0 SkyTrain Metrotown E COSE EB 378 10 4 241 3 157 40 0 142 8 TTC Bloor Toronto NB 43 0 15 3 145 5 29 4 55 0 17 0 TTC King Toronto SB 28 1 5 9 168 3 16 7 55 0 73 4 NB northbound SB southbound WB westbound EB eastbound SD standard deviation Hdwy headway 12 The operating margin is estimated to be Operating margin average headway avg station dwell 2 standard deviation of station dwell train control separation Part 3 RAIL TRANSIT CAPACITY Page 3 41 Chapter 5 Operating Issues Transit Capacity and Quality of Service Manual Exhibit 3 33 Headway Components of Surveyed North American Heavy Rail Transit Lines At or Close to Capacity seconds Vancouver BC San Francisco BART Newark Calgary New York Calgary Calgary Toronto New York Toronto Vancouver BC San Francisco Muni E Dwell 2 SD Vancouver BC Bl Train Control New York Separation O Operating Margin Newark i H g 0 50 100 150 200 250 300 Seconds Headway coefficient of A proxy for service reliability is the headway coefficient of variat
138. nwise The results are unlikely to be accurate or may reflect only a very specific sub set of users The selection of a minimum headway for AGT systems should reflect the train control separation dwell time and any operating margin that conforms with existing operations or is suggested by the system manufacturer The typical headway of airport systems is 120 seconds with a few operating down to 90 seconds Claims have been made for closer headways with some proprietary systems Headways shorter than 90 seconds are possible but may limit dwell times and constrain the operating margin They should be considered with caution unless off line stations are adopted Off line stations make closer headways possible and practical at a price LOADING LEVELS Loading levels of automated guideway transit cars tend to be atypical of normal transit operations Those systems that are integral parts of public transit networks such as the Detroit and Miami downtown people movers can use loading levels derived from Chapter 4 Passenger Loading Levels Other systems range widely At one extreme are the airport shuttles with wide cars and no or few seats where loading can reach 10 passengers per meter of length 3 p ft of length under pressure from arriving business type flights Loading diversity on airport systems fluctuates related to flight arrival times rather than 15 minute peak periods within a peak hour After an arriving flight three trains at 120 seco
139. ny schedule recovery allowance More expensive ways to improve turn backs include extending tracks beyond the station and providing crossovers at both ends of the station This permits a storage track or tracks for spare and disabled trains a useful if not essential failure management facility With crossovers at both ends of the station on time trains can turn back beyond the station with late trains turning in front of the station providing a valuable recovery time of some 90 seconds at the price of additional equipment to serve a given passenger demand JUNCTION THROUGHPUT Correctly designed junctions should not be a constraint on capacity Where a system is expected to operate at close headways high use junctions will invariably be grade separated At such flying junctions the merging and diverging movements can all be made without conflict and the only impact on capacity is the addition of the switch throw and lock times typically 3 to 6 seconds Speed limits imposed in accordance with the radius of curvature and any superelevation may reduce the schedule speed but should not raise the minimum headway unless there is a tight curve close to a headway limiting station The capacity of a flat junction can be calculated in a similar manner to the terminal station approach The junction arrangement is shown in Exhibit 3 12 Dual faced platforms and loops can reduce dwell times Allowances should be made to prevent common delays
140. ommuter rail capacity based on train length is also affected by the common use of bi level cars although few such trains currently fit into the applicable category of electric multiple unit operation Exhibit 3 49 Typical Maximum Passenger Capacities of Grade Separated Rail Transit Excluding All Seated Commuter Rail 50000 45000 40000 35000 T7 30000 25000 20000 Capacity passengers hour track 15000 10000 180 m 600 ft 150 m 500 ft 120 m 400 ft 90m 300 ft 60m 200 ft Train length NOTE Assumes peak hour average passenger loading of 5 0 p m of length for light rail and 6 0 p m of length for heavy rail Capacity for one track of a grade separated rail transit line Operating margin ranges from 45 seconds lower bound to 70 seconds upper bound Part 3 RAIL TRANSIT CAPACITY Page 3 62 Chapter 6 Grade Separated Systems Capacity Transit Capacity and Quality of Service Manual 7 LIGHT RAIL CAPACITY INTRODUCTION This chapter covers methods for determining the capacity of light rail transit lines While the approach used in Chapter 6 Grade Separated Rail Capacity will work in most situations light rail transit lines often have characteristics such as street running grade crossings and single track sections which are not covered in that chapter but which are of importance in capacity determination The key to determining the capacity of a light rail
141. ons are not met then the simple procedure may be used only as a guideline and the complete procedure that follows should be used The simple procedure does not apply to locomotive hauled commuter rail or to automated guideway transit using a proprietary system with small narrow vehicles Exhibit 3 38 Grade Separated Rail Transit Performance Assumptions Simple Method Capacity Calculation Term Description Default Unit G Grade into headway critical station t2 D distance from front of train to exit block lt 10 m lt 35 ft K service braking rate 75 96 tos time for overspeed governor to operate 3 seconds fj time lost to braking jerk limitation 0 5 seconds d pence acceleration rate 1 3 m s 43 fUs d Service deceleration rate 1 3 m s 4 3 ft s t brake system reaction time 1 5 seconds Vmax Maximum line velocity 100 km h 60 mph t4 dwell time 35 45 seconds tom Operating margin 20 25 seconds l line voltage as of normal gt 85 96 Smb moving block safety distance 50 m 165 ft The range of trains per hour are shown in Exhibit 3 39 for the above assumptions for cab control systems and in Exhibit 3 40 for moving block signaling systems New systems that are designed for maximum capacity would not use the more limited and more expensive three aspect signaling system Such a system may be used for systems designed for less than maximum throughput in which case this procedure is not a
142. oor light rail cars is the use of mini high or high range platforms that provide level loading to the wheelchair accessible door of the train This method is mechanically simple and often uses a folding bridgeplate manually lowered by the train operator to provide a path over the stepwell between the platform edge and vehicle floor The mini high platform is reached by a ramp or where space limitations require by a small lift In Sacramento one of the pioneers of mini high platforms these lifts are passenger operated and the boarding passenger must be on the mini high platform for the train operator to board them The Sacramento system handles about 1 200 wheelchairs and five times as many strollers a month on the mini high platforms Mini high platforms have been adopted for the non level loading light rail lines in Baltimore and Denver The San Francisco Municipal Railway has also installed mini high platforms at key locations on its surface lines the downtown subway is high platform The cars must make a special stop to board and alight passengers using the mini high platforms as the moveable steps on the car must be raised and the center door aligned with the platform in order for level loading to take place The steps are usually raised before the car has come to a stop An elastic gap filler is used between the platform edge and car doorway No bridge plate is needed and the train operator does not have to leave the cab This arrangement as
143. oorway simultaneously At some width below this range a doorway will be essentially single stream At widths above those surveyed a doorway will routinely handle triple streams There are no single or triple stream doors on any modern North American rail transit vehicle although they exist on AGT systems and in other countries JR East in Tokyo is experimenting with a quadruple stream doorway shown in Exhibit 3 19 Wide doors have been a characteristic of the ADtranz C100 automated guideway transit used in many airports and on Miami s MetroMover This four stream 2 4 m 8 ft door is shown below Exhibit 3 19 Quadruple Stream Doorways Tokyo Miami Estimating Dwell Times There are three methods to estimate station dwell times The first translates station passenger volumes and doorway flow rates into doorway flow times and then into dwell times This involves complex mathematics involving logarithmic transforms and depends on knowledge of station passenger movements which are often not readily available Use of this method is limited and reference should be made to Chapter 4 of TCRP Report 13 Rail Transit Capacity The second method is the traditional Mean Plus Two Standard Deviations It provides a prediction interval for a new train as opposed to one for the mean of all trains Since it is maximum capacity that is the ultimate objective only the upper limit is of interest This is of value for stations on existing systems where
144. or extended dwells due to low level step loading wheelchairs or on board fare collection With minimum headways provided by cab control signals of better than 120 seconds it is reasonable to expect level loading whether high or low and off vehicle fare collection Nor is any allowance made for headway constraints due to junctions or speed restrictions in the maximum load point station approach Where any of these situations may apply the complete procedures of Chapter 6 should be followed Predominantly segregated light rail lines with block signaling can reach the achievable capacity of some heavy rail systems At this upper end of the light rail spectrum achievable capacity calculations should follow those of heavy rail transit An alternative figure using U S customary units appears in Appendix A An alternative figure using U S customary units appears in Appendix A Part 3 RAIL TRANSIT CAPACITY Page 3 75 Chapter 7 Light Rail Capacity Transit Capacity and Quality of Service Manual Maximum light rail transit Note that no light rail lines in the U S and Canada approach volumes of 10 000 capacities passengers per peak hour direction per track except San Francisco s Muni Metro subway which is shared by five routes and Boston s Green Line subway Achievable capacities to and above 20 000 passengers per peak hour direction are reported in Europe however at these levels the lines often called light metro pre metro or U
145. or modern air brake equipment til jerk limiting time 0 5s Part 3 RAIL TRANSIT CAPACITY Page 3 93 Chapter 11 Example Problems Transit Capacity and Quality of Service Manual Maximum light rail capacity for on street operation with signalized intersections and one or three car trains Substituting the variables in the equation produces 228 6 25 E 15 3 0 1 1 5 3 15 3 H s 24 1 t 1 3 0 5 0 15 3 75 2 1 3 1 0 1 1 5 2 15 3 222 H s 15 3 2 33 6 92 0 440 0 31 1 3 0 5 0 H s 35 1 seconds c Incorporating station dwells and an operating margin Controlling dwell is average dwell time plus twice the dwell time standard deviation To determine the headway that can be operated under the conditions given station dwell times and an operating margin must be incorporated The line headway is controlled by a controlling dwell Chapter 4 gives a number of methods of estimating the controlling dwell time from dwell time data The approach used here estimates the controlling dwell by taking the average dwell time at the controlling dwell station and adding twice the dwell time standard deviation This method produces a result that also incorporates an operating margin to allow for minor irregularities of operation Controlling dwell avg dwell 2 dwell time standard including operating margin E time deviation J 30 sec 2 21 sec 72 sec Combining this result with the minimum train separ
146. ow two minutes In this chapter the limitations on headway will be calculated for all three possible bottlenecks station stops junctions and turnbacks Station Close In Time The time between a train pulling out of a station and the next train entering referred to as close in is the main constraining factor on rail transit lines This time also known as the safe separation time is primarily a function of the train control system train length approach speed and vehicle performance Close in time when added to the dwell time and an operating margin determines the minimum possible headway achievable without regular schedule adherence impacts referred to as the non interference headway Exhibit 3 4 shows a distance time station stop diagram The best method to determine the close in time is from the specifications of the system being considered from existing experience of operating at or close to capacity or from a computer simulation model Such models can provide an accurate indication of the critical headway limitation whether a station close in maneuver at a junction or at a turnback If a model or actual operating data are not available then minimum headway can be calculated from Equation 3 4 The derivation of this equation and additional information on line versus station headways is available in TCRP Report 13 Part 3 RAIL TRANSIT CAPACITY Page 3 12 Chapter 2 Train Control and Signaling Transit Capacity and Q Exhibit
147. pplicable Consequently the choice of train control system is limited to cab control and moving block This is a method to determine the maximum capacity of a rail transit line Consequently train lengths are shown for typical maximum lengths of 200 and 150 meters 660 and 500 feet trains of 8 and 6 heavy rail cars and 120 90 and 60 meters 400 300 and 200 feet trains of 4 3 and 2 articulated light rail vehicles respectively Part 3 RAIL TRANSIT CAPACITY Page 3 49 Chapter 6 Grade Separated Systems Capacity Transit Capacity and Quality of Service Manual Exhibit 3 39 Cab Control Throughput 44 43 42 41 40 39 Lo 38 37 L 36 35 34 33 32 31 30 p p X p pem peo ee y Boas 2 er M Mtl x c o dp Ap i i pd Throughput trains h 28 27 26 180 m 600ft 150 m 500 ft 120m 400ft 90m 300f t 60m 200ft Train Length NOTE Total of operating margin and dwell time ranges from 55 seconds lower bound to 70 seconds upper bound Exhibit 3 40 Moving Block Variable Safety Distance Throughput 52 51 50 49 48 47 46 45 44 43 42 41 40 39 38 37 36 35 34 180 m 600 ft 150 m 500 ft 120m 400ft 90m 300ft 60m 200ft Throughput trains h Train Length NOTE Total of operating margin and dwell time ranges from 55 seconds lower bound to 70 seconds upper bound Part 3 RAIL TRANSIT CAPACITY Page 3 50 Chapter 6 Grade Separated Systems
148. r longitudinal seating The result in lowest whole numbers should then be multiplied by two for longitudinal seating or by 3 4 or 5 respectively for 2 1 242 or 243 transverse seating The result is the total number of seats A more exact method would use the specific length between door setbacks Articulated light rail vehicles should have the articulation width deducted Four seats can be assigned to the articulation if desired The floor space occupied by seats can then be calculated by multiplying transverse seats by 0 5 m 5 4 ft and longitudinal seats by 0 4 m 4 3 f These areas make a small allowance for a proportion of bulkhead seats but otherwise represent relatively tight and narrow urban transit seating Add 10 to 20 for a higher quality larger seat such as found on BART The residual floor area can now be assigned to standing passengers Light rail vehicles with step wells should have half the step well area deducted Although prohibited by many systems passengers will routinely stand on the middle step squeezing into the car at stops if the doors are treadle operated Articulated light rail vehicles should have half the space within the articulation deducted as unavailable for standing passengers even if the articulation is wider Many passengers choose not to stand in this space Standing passengers can be assigned as follows e 5 passengers per square meter or 0 2 m 2 15 ft per passenger an uncomfortabl
149. r rail transit modes is that commuter rail trains are often stored at the downtown terminals during the day This reduces the need for track capacity in the off peak direction and allows a higher level of peak direction service to be operated Metro North in New York with 4622 platform tracks at Grand Central Terminal is thus able to use three of its four Park Avenue tunnel tracks in the peak direction Even when one of the tunnel tracks was closed for reconstruction 23 trains per hour were handled on the remaining two peak direction tracks 22 There is some variation between sources regarding the size of Grand Central Terminal Metro North reports 46 platform tracks A number of other sources give the station a total of 67 tracks including storage and maintenance tracks Page 3 78 Chapter 8 Commuter Rail Capacity Transit Capacity and Quality of Service Manual The situation at New York s Penn Station is less relaxed The Long Island Rail Road has exclusive use of five tracks and shares four more with Amtrak and New Jersey Transit Currently the LIRR operates the East River tunnels with two tracks inbound and two tracks outbound with a peak headway of three minutes per track With limited station capacity two thirds of LIRR trains continue beyond Penn Station to the West Side Yard However not all tracks used by the LIRR at Penn Station continue to the yard and some trains must be turned in the station This can be done in as little as 3
150. rains that can be operated because of interlockings and grade crossings with other railroads Unlike the capacity determination methodologies for other modes commuter rail is not provided with both simple and complete methods for determining achievable capacity Once the number of trains that can be operated in an hour has been determined the capacity is not dependent on loading standards but only on the number of seats provided on a train TRAIN THROUGHPUT Determining train throughput requires consulting the railroad agreement or the railroad or agency signaling engineers to determine the maximum permitted number of commuter trains per hour Generally these numbers will be based on a train of maximum length so the length headway variations of Chapter 2 Train Control and Signaling will not enter into the picture Commuter rail capacity determination is both simple and inexact Transit agency ownership of track used for commuter rail Part 3 RAIL TRANSIT CAPACITY Page 3 77 Chapter 8 Commuter Rail Capacity Transit Capacity and Quality of Service Manual Train throughput where commuter rail has exclusive occupancy of the track Operating practices and patterns Train storage at downtown terminals Part 3 RAIL TRANSIT CAPACITY A definitive answer may not always be obtained particularly with single track sections that are shared with freight Freight traffic can be seasonal and available commuter rail trips can vary Usual
151. rate 1 3 m s or 4 3 fus Part 3 RAIL TRANSIT CAPACITY Page 3 13 Chapter 2 Train Control and Signaling Transit Capacity and Quality of Service Manual An alternative version of this figure in U S customary units appears in Appendix A Optimum approach speeds Switches turnouts and curves impose speed restrictions The vertical bars show the AREA recommended speed limit range for lateral and equilateral level turnouts of size 6 8 and 10 Note that many operators have their own speed limits for turnouts that may differ from those shown Transition spirals are not taken into account An alternative version of this figure in U S customary units appears in Appendix A Using these typical values Equation 3 4 produces the results of Exhibit 3 5 where B 2 4 for three aspect signaling and B 1 2 for multiple command speed cab controls Exhibit 3 5 Station Headway for Lines at Capacity 170 160 150 140 Headw ay s 130 120 110 Approach speed km h Exhibit 3 5 shows that the optimum approach speed for three aspect signaling is 47 km h 29 mph and for multiple command speed cab controls 52 km h 32 mph If special work interlockings or curves restrict approach speeds below these values then the lower values must be calculated and used Typical speed limits for switches and curves are shown in Exhibit 3 6 Determine any such station approach speed restrictions and their distance from
152. re takes two to three minutes giving a total train delay including loading and unloading of four to six minutes per passenger requiring the lift These delays can easily consume the train s scheduled terminal recovery time An average of 25 wheelchairs and scooters are carried each weekday on the San Jose light rail line but this has increased to as many as 50 a day for special events Tri Met in Portland removed its platform lifts in 1997 after adding a low floor car to each train The Portland wayside lifts were more efficient than the San Jose device Under normal circumstances the lift was at ground level ready to receive boarding passengers The presence of the passenger on the lift signaled the passenger s intention to board to the train operator The train operator then aligned the first door of the train with the lift and boarded the passenger The car s steps were bridged by a folding plate on the lift This configuration speeded the use of the lift but did not prevent it from having an effect on punctuality as the time for each mobility device movement averaged 1 minute 50 seconds 19 Based on San Diego Trolley data for May 1994 Out of 1 069 lift passengers carried 2 138 lift cycles only six failures were recorded giving a failure rate of 0 28 Part 3 RAIL TRANSIT CAPACITY Page 3 72 Chapter 7 Light Rail Capacity Transit Capacity and Quality of Service Manual Mini High Platforms The most common wheelchair access to high fl
153. recommended typical dwell time of 40 seconds and the recommended operating margin of 25 seconds would result in a minimum headway of 78 4 seconds This should be rounded up to 80 seconds Chapter 9 states that headways shorter than 90 seconds are possible but may limit dwell times and constrain the operating margin They should be considered with caution unless off line stations are adopted As the developer has indicated a relatively relaxed loading level it is realistic to expect dwells to be lower than normal and hence the 80 second headway can be accepted as practical This equates to 3600 80 or 45 trains an hour The 25 meter long platform can hold two 12 m cars a common AGT size and comparable to a city bus As no specific car design can be assumed it is reasonable that wide double doors will take up 4 meters of each car side leaving 8 meters for seating At a pitch of 900mm this allows 8 rows of seats The seats will be 2 2 with five abreast at each end there are no driving cabs on an automated AGT Such a car can thus accommodate 8 x 4 2 for a total of 34 seats The desired maximum of half the passengers standing brings the total car passenger capacity to 68 Note that an AGT car of this size on a short distance line would normally be rated for 100 passengers most of whom would stand The resultant maximum capacity at the preferred loading level is 3 060 passengers per peak hour direction As always with such calculations where there ar
154. res in both methods include the rail transit operations variables that affect capacity The procedures compensate for the differences between design capacity and achievable capacity the actual sustainable peak hour capacity Chapter 11 presents example problems that demonstrate how to apply the capacity procedures presented in Part 3 Appendix A provides substitute exhibits in U S customary units for Part 3 exhibits that use metric units GROUPING For capacity analysis heavy rail light rail commuter rail and automated guideway transit are grouped into unique categories based on alignment equipment train control and operating practices The first category is fully segregated signaled double track right of way operated by electrically propelled multiple unit trains This is the largest category encompassing all rail rapid transit including automated routes several light rail sections for example the Market Street subway in San Francisco and several commuter rail lines This category is termed Grade Separated Rail The second category is light rail without fully segregated tracks divided into on street operations and right of way with grade crossings Streetcar only operations Toronto and New Orleans form a subset of the on street section The third category is commuter rail other than services in category one The fourth category includes automated guideway transit routes that are intended to serve a single major act
155. rm are a poor compromise would be adjacent to a platform at all stations This would only work if the platforms at major terminal stations could accommodate all the cars of each train As this complicates train operations and would likely create passenger confusion the option of purchasing two level cars is preferable Part 3 RAIL TRANSIT CAPACITY Page 3 97 Chapter 11 Example Problems Transit Capacity and Quality of Service Manual Automated guideway transit with short trains In practice trains cannot run as close as suggested by theory Example Problem 6 The Situation A feeder line is planned from a new suburban office development to an existing heavy rail station The Question Based on use the of advanced train control systems what is the maximum capacity of this line The Facts The developer wants to incorporate the automated guideway transit stations in an elevator lobby on the second floor of each building which limits station length to 25 meters Although the line is short the developer wants to offer a high quality service in which half of all passengers are seated Most AGT systems are proprietary and the manufacturer would provide capacity capabilities In this case the developer does not wish to approach a manufacturer at this stage Outline of Solution Exhibit 3 58 shows that an AGT moving block train control system can provide a minimum train separation of 13 4 seconds with 25 meter long trains Adding the
156. rt 3 RAIL TRANSIT CAPACITY Page 3 38 Chapter 4 Passenger Loading Levels Transit Capacity and Quality of Service Manual 5 OPERATING ISSUES INTRODUCTION The previous three chapters have introduced the three major components that control rail transit capacity Train Control and Signaling Station Dwell Times and Passenger Loading Levels Operating issues discussed in this chapter affect all three components There is considerable uniformity of performance of the electrical multiple unit trains that handle over 9096 of all North American rail transit assisted by the wide spread introduction of electronic controls and automatic driving However there still can be up to a 10 difference in performance between otherwise identical trains due to manufacturing tolerances aging of components and variances in set up parameters and in particular on manually driven systems due to variation in driving techniques and between drivers To accommodate these routine irregularities two allowances are made in rail transit operations planning and scheduling An operating margin is added to the minimum train separation time and maximum load point station dwell time to create a minimum headway This operating margin is in effect the amount of time a train can run behind schedule without interfering with the following trains The operating margin is an important component in determining the maximum achievable capacity The second allowance is schedule re
157. rted values are the minimums using typical maximum rail transit performance criteria and without applying any corrections for grades or speed restrictions into or out of the station Step 3 Determining the Dwell Time This section deals with station dwell times to which both an operating margin and the minimum train signal system separation must be added to produce the headway The train close in time at the headway critical station being dependent on the physical performance and length of a train and other fixed system characteristics can be calculated with some precision Station dwell time cannot be determined with the same exactitude All but one of literature references related to rail transit capacity assigned a set time to dwell time Many simulations do likewise using typical figures of 15 20 seconds for lesser stations and 30 45 seconds for major stations The one methodology to determine controlling dwell dwell time plus operating margin requires knowledge of station dwell times over the peak hour information only available for existing systems or new lines in areas where a station with similar passenger volumes can be analyzed Chapter 3 Station Dwell Times describes the main constituents of dwell time as follows e passenger flow time at the busiest door e remaining unused door open time and e waiting to depart time with doors closed Four methods of estimating dwell time or controlling dwell time are provided i
158. s oo Estimating the person capacity of a vehicle Seating area Standing area Part 3 RAIL TRANSIT CAPACITY Page 3 31 Chapter 4 Passenger Loading Levels Transit Capacity and Quality of Service Manual The articulated rail car schematic Exhibit 3 23 shows the principal dimensions of this equation e 3 3 passengers per square meter or 0 3 m 3 2 ft per passenger a reasonable service load with occasional body contact Moving to and from doorways requires some effort e 2 5 passengers per square meter or 0 4 m 4 3 ft per passenger a comfortable level without body contact reasonably easy circulation and similar space allocation as seated passengers The middle level above is slightly relaxed from the often stated standard of four standing passengers per square meter The so called crush loads are frequently based on 5 or 6 passengers per square meter 2 2 to 1 8 ft p the latter being more common in Europe Asian standards for both maximum and crush loads reach 7 or 8 standing passengers per square meter 1 5 to 1 3 ft p The resultant sum of seated and standing passengers provides a guide for the average peak 15 minute service loading level for the specific vehicle Peak hour loading should be adjusted by the vehicle loading diversity factor No specific allowance has been made for wheelchair accommodation or for reduced standing densities away from doorways The above range of standing densities makes such smal
159. s shown in Exhibit 3 35 have the least impact on capacity Exhibit 3 35 Wheelchair Loading Platform and Ramp LEE Part 3 RAIL TRANSIT CAPACITY Page 3 45 Passenger flow rates though turnstiles and exit gates On board light rail fare payment Platform width Chapter 5 Operating Issues Transit Capacity and Quality of Service Manual Folding steps and profiled platforms Wheelchair usage Capacity reduction due to wheelchair space requirements An alternate to the mini high platform is the Manchester style profiled platform shown in Exhibit 3 36 This platform has an intermediate height and is profiled up to a section that is level with one doorway for wheelchair access All slopes are a maximum of 8 5 to meet Americans with Disabilities Act ADA requirements Most of the platform is only slightly higher than a sidewalk Where the street arrangement permits the profiled platform can be raised so that its mid section taking up most of the length is raised one step providing a single step entry to most doors Alternately the cars can have a slide or fold out step as shown in Exhibit 3 37 Exhibit 3 36 Profiled Light Rail Platform Providing For One Wheelchair Accessible Door I Exhibit 3 37 Profiled Light Rail Platform with Slide Out or Fold Down Step D Of concern is the number of wheelchairs that will elect to use mainstream rail transit when all ADA measure
160. s have been implemented A 1995 survey of heavily used rail transit systems indicated an average of one wheelchair use per 20 000 passengers Other estimates range from one in 5 000 to one in 10 000 However the usage of lifts can be three to five times higher than this due to use by other passengers not in wheelchairs As well as boarding and alighting delays the time for a wheelchair to move to the stow position and use any required tie downs can be considerable particularly if the rail car is crowded The least loss of time is where the wheelchair position is close to the doorway and requires neither a folding seat nor tie downs Some agencies are overly cautious adopting bus tie down practice to light rail service Experience on many rail systems indicates that tie downs are not necessary on rail service as braking and acceleration is closely controlled and ride quality is smooth There are many other types of boarding and alighting delays from passengers other than those in wheelchairs and generally these are accommodated in the operating margins and schedule recovery times There is still insufficient information to quantify any impact of ADA on the achievable capacity of rail transit systems However indications are that in the short term wheelchair lift use on light rail may cause delays but this use is generally on systems with long headways 6 minutes and above and have minimal impact at these levels In the longer term other requiremen
161. s provide a coarse indication of train location A minimum of two empty blocks is required between trains for a two aspect system Part 3 RAIL TRANSIT CAPACITY Page 3 9 Chapter 2 Train Control and Signaling Transit Capacity and Quality of Service Manual Cab signaling sets authorized safe train speeds Moving block signaling is based on the use of target points designed for 44 and 48 trains per hour by far the closest train spacing on any rail system irrespective of technology Requiring a driver to control a train s speed and commence braking according to multiple aspect color light signaling requires considerable precision to maximize throughput Cab signaling provides assistance in this regard and reduces capital and maintenance costs CAB SIGNALING Cab signaling uses codes inserted into each track circuit and detected by an antenna on each train The code specifies the maximum allowable speed for the block occupied and may be termed the reference or authorized speed This speed is displayed in the driver s cab often so that the authorized speed and actual speed can be seen together The authorized speed can change while a train is in a block as the train ahead proceeds allowing drivers to adjust train speed close to the optimum with less concern about overrunning a trip stop Problems with signal visibility on curves and in inclement weather are reduced or eliminated Cab signaling avoids much of the capital and
162. sengers preferring to stand for shorter trips A capacity of 7 passengers per meter 2 1 p ft can be used as a maximum A range of 5 p m 1 5 p ft is the upper end for single level cars with 4 p m 1 2 p ft preferred These preferred and recommended levels allow some space for toilets wheelchairs and bicycles If these provisions are extensive then the car capacity should be reduced accordingly Obviously the train length should exclude the length of the locomotive s and any service cars and should be adjusted for any low density club bar or food service cars An allowance for standing passengers is not recommended However if the nature of the service has significant short trips it may be appropriate to add 1096 to the number of seats on the train Heavy rail standing densities are not appropriate for commuter rail 24 Another common station limitation lack of park and ride capacity is considered in Chapter 5 25 Also called tri levels on certain systems as there is an intermediate level at each end over the trucks Page 3 80 Chapter 8 Commuter Rail Capacity Transit Capacity and Quality of Service Manual Exhibit 3 57 Commuter Rail Car Capacity System and City Car Designation Date Built Seats Seats m ft Bi level cars LIRR New York C 1 Bee 190 E 2 4 MBTA Boston BTC 1991 185 73 2 3 MBTA Boston CTC Be 180 es 2 3 GO Transit Toronto Bi Level Trailer 1977 91 162 6 3 2 1 Metra
163. served on PATH when passengers were boarding empty trains at the exit and summarized by type of flow in Exhibit 3 17 Doorway steps double Exhibit 3 17 Summary of Rail Transit Average Door Flow Times Medium Volume Level Doorway High Volume Level Doorway Light Rail with Steps Only Light Rail with Steps amp On board Fares Boarding E Alighting El Mixed Flow 0 1 2 3 4 5 6 Time per passenger per single stream seconds An interesting result is that passengers enter high floor light rail vehicles faster from Journal Square station in Newark in the morning peak These flow data are consolidated The results show that in these averages there is little difference between the high boarding and alighting times volume older East Coast heavy rail transit systems and the medium volume systems newer light rail and heavy rail transit Doorway steps approximately double times for all three categories mixed flow boarding and alighting Light rail boarding up steps with exact fare collection adds an average of almost exactly one second per passenger compared to peak period flows as summarized in Exhibit 3 18 Special event passenger rates were found to be slower than weekday peak rates Part 3 RAIL TRANSIT CAPACITY Exhibit 3 18 BC Transit SkyTrain Door Flow Rate Comparisons Football Game
164. sible predictive control where a computer looks ahead to possible conflicts for example a merge of two branches at a junction The computer can then adjust terminal departures dwell times and train performance to ensure that trains merge evenly without holds The non vital ATS system can also be the host for other features such as on board system diagnostics and the control of station and on board information through visual and audio messages including those required by the Americans with Disabilities Act ADA FIXED BLOCK THROUGHPUT Determining the throughput of any rail transit train control system relies on the repetitive nature of rail transit operation In normal operation trains follow each other at regular intervals traveling at the same speed over the same section of track All modern heavy rail rolling stock has comparable performance Stations are the principal limitation on the maximum train throughput In a well designed and operated system junction or turnback constrictions or bottlenecks should not occur A flat junction can theoretically handle trains with a consolidated headway approaching two minutes However delays may occur and systems designed for such close headways will invariably incorporate grade separated flying junctions Moving block signaling systems provide even greater throughput at flat junctions A two track terminal station with either a forward or rear scissors cross over can also support headways bel
165. sing the typical parameters in the square brackets above resulting in a junction limiting headway of 102 seconds plus an operating margin While in theory this should allow a 120 second headway with a flat junction it does not leave a significant operating margin and there is a probability of interference headways General guidance in rail transit design is that junctions should be grade separated for headways below 150 to 180 seconds Advantage of sophisticated An exception is with a moving block signaling system incorporating an automatic supervision to reduce train supervision system with the capability to look forward and so adjust train junction conflicts performance and station dwells to avoid conflicts at the junction i e trains will not have to stop or slow down at the junction other than for the interlocking s track design speed limit In this case the junction interference headway drops to 63 seconds allowing 120 second or slightly lower headways to be sustained on a flat junction a potentially significant cost saving associated with a moving block signaling system Part 3 RAIL TRANSIT CAPACITY Page 3 20 Chapter 2 Train Control and Signaling Transit Capacity and Quality of Service Manual SUMMARY Using as few approximations as possible the minimum headway can be calculated Results match actual field for a range of train control systems with a wide number of variables The results are ee vere summarized in Exhibit 3
166. stem manufacturer or designer Using the methodology of Chapter 3 should be a last resort when specific train separation information is not available Part 3 RAIL TRANSIT CAPACITY Page 3 84 Chapter 9 Automated Guideway Transit Capacity Transit Capacity and Quality of Service Manual PASSENGER FLOW RATES AND DWELLS AGT systems that are part of a normal transit system can assume flow rates and station dwell times as determined in Chapter 3 Station Dwell Times However most AGT systems are classed as institutional and the majority of passengers are unlikely to be regular experienced transit users Doorways are rarely of typical transit width or configuration The most common arrangement is the quadruple flow door with associated platform doors shown in Exhibit 3 61 Exhibit 3 61 Orlando Airport People Mover Doorways aera sn Tom Parkinson P Eng 1992 Doorway flow rates and the associated station dwell times were monitored on the three C 100 systems at the Seattle Tacoma Airport in May 1995 The range of users varied greatly and included many people with baggage and a few with baggage carts After the arrival of a full flight with a preponderance of business passengers passenger flow rates reached and exceeded standard transit doorway flow rates At other times doorway flow rates were often well below the transit rates documented in Chapter 3 Under these circumstances calculating flow times and from them dwell times is u
167. t 24 5 meter long cars can carry 8 x 7 x 24 5 1 372 passengers Multiplying this figure by the number of trains per hour provides passengers per peak hour direction per track of 41 160 ppphd and 49 360 ppphd respectively Reflecting the approximations used in this determination the results should be rounded down to the nearest 1 000 41 000 and 49 000 If a lower ratio of standing passengers is desired these maximum calculated capacities can be down rated further by 20 30 Part 3 RAIL TRANSIT CAPACITY Page 3 91 Chapter 11 Example Problems Transit Capacity and Quality of Service Manual Heavy rail line with junction Attempt to save money using flat junction Calculations concur with rule of thumb that junctions should be grade separated at headways below three minutes Part 3 RAIL TRANSIT CAPACITY Page 3 92 Chapter 11 Example Problems Example Problem 2 The Situation The transit agency from Example 1 has decided to use a variable safety distance moving block signaling system The agency would now like to know if it can economize on construction by building a flat junction at a point where two of its lines diverge The agency s long term plan is to run a two minute headway through the junction The Question Can a flat junction on this proposed system support a two minute headway or must a flying junction be constructed The Facts Many of the variables are the same as those used in the previous example In addition the a
168. t trunk routes in New York have three or four tracks while the Broad Street subway in Philadelphia and the North Side elevated in Chicago have four tracks The capacity of four track lines is not a simple multiple of two single tracks and varies widely with operating practices such as the merging and dividing of local and express services and trains holding at stations for local express transfers The result is that four tracks rarely increase capacity by more than 5096 over a double track line and often less A third express track does not necessarily increase capacity at all when restricted to the same station close in limitations at stations with two platform faces Design capacity has two factors line capacity and train capacity and can be expressed as C C xC Equation 3 1 where Cp design capacity p h CL line capacity trains h and Cr train capacity p train In expanded form design capacity is given by Equation 3 2 3 All but two New York three and four track trunks merge or split into double track sections tunnels or bridges crossing the Harlem and East Rivers often with one crossing used for local trains and a second used for express services The Concourse line used by the C and D trains and the Seventh Avenue Broadway line used by the 1 and 9 trains are the only three track river crossings The Manhattan Bridge carries four tracks but only two are in service Part 3 RAIL TRANSIT CAPACITY Page 3 2
169. tain an operating margin or a margin can be added separately to the denominator of the expression Chapter 3 Station Dwell Times develops the methodology and analysis of dwells Chapter 5 Operating Issues discusses and develops operating margins DESIGN VERSUS ACHIEVABLE CAPACITY This manual provides guidelines and methods that can be used for real world evaluation of rail transit capacities The difference between design and achievable capacity is an important consideration Design capacity in passengers per hour per direction pphpd is calculated using the following factors e number of seats per car e number of standees per car standing area x standee density e number of cars per train and e train headway minimum headway determined by a combination of the signaling system station dwell and terminus constraints Minimum headway and close in time Controlling dwells Part 3 RAIL TRANSIT CAPACITY Page 3 3 Chapter 1 Rail Capacity Basics Transit Capacity and Quality of Service Manual Capacity reduction from real world factors Achievable capacity approximated using peak hour factors Additional factors affecting achievable headway Station dwell effects on productivity and service attractiveness This approach does not incorporate factors that reduce the actual number of regular riders that the system can sustain e Standing densities vary people will crowd in more tightly in some situations t
170. target point will be based on the normal braking distance for that train plus a safety distance The safety distance is the maximum distance a train can travel after it has failed to act on a brake command before automatic override or overspeed systems implement emergency braking Without track circuits to determine block occupancy a moving block signaling system must have an independent method to accurately locate the position of the front of a train then use look up tables to calculate its end position from the length associated with that particular train s identification The first moving block systems used a wire laid alongside or between the running rails periodically transposed from side to side The wire transmits signals to and from antennas on the train while counting the transpositions determines location The use of exposed wayside wires is a maintenance problem and refinements use inert transponders located periodically along the track These are interrogated by a radio signal from each train and return a discrete location code Positioning between Part 3 RAIL TRANSIT CAPACITY Page 3 10 Chapter 2 Train Control and Signaling Transit Capacity and Quality of Service Manual transponders relies on the use of a tachometer Communications to and from the train are then radio based with protocols to ensure safety reliability and that messages are received by and only by the train they are intended for The computers that calcula
171. tation dwells 6 Some Russian systems using multiple aspect cab control signaling systems operate at headways down to 90 seconds by strict control of station dwell times on occasion closing doors before all passenger movements are complete This is probably not an acceptable practice in North America Station dwell times are a major component of headway Controlling dwells Peak period dwell times on four selected systems Regularity of fully automated systems There is great variance in dwell times between doors of a train and between stations in a system the data shown is from doors with the heaviest flow at the busiest station Dwell reductions made possible by automation are often offset by slack operating procedures Part 3 RAIL TRANSIT CAPACITY Page 3 23 Chapter 3 Station Dwell Times Transit Capacity and Quality of Service Manual Note that the scale of the Grand Central Station chart is twice that of the other charts in this series These four charts are representative of 61 data sets of door flows collected in early 1995 for the TCRP Rail Capacity study Data are from systems operated at or close to the capacity of their respective train control systems The data represent the movement of 25 154 passenger trains over 56 peak periods two base inter peak and three special event times at 27 locations on 10 systems Each bar represents an observation of an individual train Part 3 RAIL T
172. te 4 3 2 0 ds ft s service deceleration rate 4 3 3 3 tbr S brake system reaction time 1 5 0 5 Vmax mph maximum line velocity 60 50 mbsq ft moving block safety distance 165 80 Part 3 RAIL TRANSIT CAPACITY Page 3 106 Appendix A Exhibits in U S Customary Units
173. te and control a moving block signaling system can be located on each train at a central control office dispersed along the wayside or a combination of these The most common arrangement is a combination of on board and central control office locations Safety Issues Safety on rail transit is a relative matter It encompasses all aspects of design maintenance and operations In fixed block signaling electrical interlockings switch and signal setting are controlled by relay logic A rigorous discipline has been built around this long established technology which the use of processor based controls is now infiltrating A moving block signaling system is inherently processor controlled Processor based train control systems intrinsically cannot meet the fail safe conventions of traditional signaling Computers microprocessors and solid state components have multiple failure opportunities and cannot be analyzed and tested in the same way as conventional equipment Instead an equivalent level of safety is provided based on statistical failure modes of the equipment Failure analysis is not an exact science Although not all failure modes can be determined the statistical probability of an unsafe event can be predicted HYBRID SYSTEMS There are times when an urban rail transit system shares tracks with other services such as long distance trains whose equipment is impractical or uneconomic to equip with the moving block signaling syste
174. tem Other Capacity Issues Car loading levels for light rail transit for use in the equations in this chapter should be determined with reference to the passenger loading standards for light rail transit in Chapter 4 Passenger Loading Levels Light rail loading levels are generally lighter than those for heavy rail transit but not as generous as the one seat per passenger policy common on commuter rail Light rail train lengths are more restricted than for heavy rail transit or commuter rail because of lower car and coupler strengths and street block and station platform lengths These issues are considered under Train Length and Station Limitations later in this chapter One additional issue that is of particular importance to light rail operations and capacity is the method of access for passengers with mobility limitations While the speed of each access method varies all can have an effect where close headways and tight scheduling prevail The overall discussion of the impact of the Americans with Disabilities Act related to wheelchair provisions is contained in Chapter 4 Operating Issues More specific light rail accessibility issues are dealt with under Wheelchair Accessibility Effects in this chapter The key is finding the weakest link Range of light rail right of way types Light rail loading levels Light rail train lengths Access for passenger with mobility limitations Part 3 RAIL TRANSIT CAPACITY Page 3 63 Chap
175. ter 7 Light Rail Capacity Transit Capacity and Quality of Service Manual Single track reduces capital costs but can add a serious capacity constraint Determining the potential extent of single track Single track occupancy time and distance Single track capacity constraints are site specific SINGLE TRACK Single track is the greatest capacity constraint on light rail lines where it is used extensively Single track sections are used primarily to reduce construction costs Some lines have been built with single track as a cost saving measure where the right of way would permit double track In other areas single track has been built because widening the right of way and structures is impossible Single track sections can be very short in order to bypass a particular obstacle for example an overpass of a highway While determining the potential extent of single track construction is possible the exact layout is highly system specific Estimates can be made of the number of track kilometers or miles required for a certain number of route kilometers or miles once the intended headway is known 7 While this does not tell the user where the single track sections can be used it can provide assistance in determining the possible extent of single track for use in cost estimates Calculating Single Track Headway Restrictions Single track sections greater than 400 500 meters 0 25 0 30 miles are potentially the most restrictive capa
176. termining the safety distance represents an eight second difference in the minimum headway Voltage fluctuations have little effect on moving block headways as the time to clear the platform is not a component in calculating the moving block signaling system headway Exhibit 3 10 Moving Block Headways with 45 Second Dwell and 20 Second Operating Margin Compared with Conventional Fixed Block Systems 170 FSD fixed safety distance 50 m 160 VSD variable safety distance 150 Pe 6 25 m grade level 140 eae ees ei ee e 130 120 IS PX 110 C al U o RE RR RUE C ER L mn s LL LL LL LL LL ILS I d 20 30 40 50 60 70 8 0 10 0 90 100 Headw ay s Approach speed km h Clear capacity increases with a moving block signaling system An alternative version of this exhibit appears in Appendix A Part 3 RAIL TRANSIT CAPACITY Page 3 17 Chapter 2 Train Control and Signaling Transit Capacity and Quality of Service Manual Turn backs should not be a constraint on capacity TURN BACK THROUGHPUT Correctly designed and operated turn backs should not be a constraint on capacity A typical terminal station arrangement with the preferred center island platform is shown in Exhibit 3 11 Exhibit 3 11 Terminal Station Track Layout y T a E The worst case is based on the arriving train lower left being held at the cross over approach signal while a train departs It must moving fro
177. that passengers with pushchairs and many wheelchair users elect to navigate the gap without this assistance While low floor cars have operated in Europe for over a decade the first North American operation began in Portland in 1997 Boston has also ordered low floor cars to make its Green Line subway surface routes accessible As in Portland the cars will be compatible with the agency s existing high floor fleet to allow mixed train operation Low floor cars have some drawbacks which have yet to be fully resolved Although purchase prices have been falling cars with a 100 low floor are more expensive to buy and maintain Certain designs are technically complex and have suffered extensive 20 Note the difference between the terms low flow car and low level loading The former states that the majority of the floor of the car is slightly above curb height the latter describes cars low floor cars included where passengers can enter from street level without the need for platforms 2 Certain low floor designs ramp down the doorways to achieve a 280 300 mm 13 14 inch floor height The most common wheelchair loading arrangement Second train stops for mini high platforms Drawbacks of low floor designs Part 3 RAIL TRANSIT CAPACITY Page 3 73 Chapter 7 Light Rail Capacity Transit Capacity and Quality of Service Manual Low floor cars in North America Full and partial low floor designs Determining the weakest link for lig
178. the cross over location in subways If passenger dwell is a limiting factor then this can be reduced with the use of dual faced platforms At terminals with exceptionally heavy passenger loading multiple track layouts may be needed An unusual alternative used at SEPTA s 69 Street and PATH s World Trade Center termini are loops with the exception of several examples in Paris these are rare luxuries for heavy rail transit Crew turnaround time can be expedited with set back crewing At a leisurely walking pace of 1 m s 3 ft s it would take 200 seconds for a driver to walk the length of a 200 m 660 ft train more if the driver were expected to check the interior of each car for left objects or passengers Obviously this could not be accommodated reliably in a 175 second terminal layover time Terminal arrangements should accommodate some common delays An example would be the typical problems of a train held in a terminal for a door sticking problem waiting for police to remove an intoxicated passenger or for a cleaning crew to perform minor cleaning Alternately one track may be pre empted to store a bad order train On these occasions the terminal is temporarily restricted to a single track and the maximum terminal layover time is reduced to 61 seconds with the above parameters 70 seconds without an approach stop This may be sufficient for the passenger dwell but cannot accommodate changing ends on a long train and totally eliminates a
179. the future However underground stations should have the full length cavity excavated otherwise it can be difficult and expensive to extend platforms while the rail line is operating Simple Procedure With the relative uniformity in the performance of electric multiple unit trains in urban rail transit service a simple procedure can be applied to estimate a range of achievable peak hour passenger capacities for grade separated lines at their maximum capacity Part 3 RAIL TRANSIT CAPACITY Page 3 48 Chapter 6 Grade Separated Systems Capacity Transit Capacity and Quality of Service Manual The necessary choices are only two the type of train control system and the train length The range is provided by assigning 1 a range centered around a typical dwell time plus operating margin and 2 a small loading range centered around the recommended peak hour average space per passenger of 0 5 m 5 4 ft As this is a peak hour average no loading diversity factor is required This simple procedure assumes system and vehicle characteristics that are close to Simple capacity model the industry norms listed in Exhibit 3 38 It also assumes that there are no speed assumptions restrictive curves or grades over 2 on the maximum load point station approach and that the power supply voltage is regulated within 15 of specifications The procedure as does the study as a whole assumes an adequate supply of rolling stock If any of these assumpti
180. the sections that follow Chapter 5 Operating Issues has discussed general capacity issues related to the Americans with Disabilities Act including typical light rail provisions Boarding and alighting times with non level loading of wheelchairs tend to be highly variable depending on the skill of the passenger Experienced users can be remarkably quick in boarding and alighting Passenger movement times are often lower than for lift equipped buses as there is more room to maneuver wheelchairs walkers and scooters in light rail vehicles Off vehicle fare collection also helps to speed loading for mobility limited and able bodied passengers alike Some agencies require the passenger and wheelchair to be strapped in a time consuming process which is becoming less common as the policy is not justified by the relatively low deceleration rates experienced on light rail vehicles Some systems have experienced passenger conflicts over mobility device seating priority when other passengers occupy the folding seats provided to create space for wheelchairs and other mobility devices It should be noted that both mobility impaired passengers and transit agencies prefer access methods which do not single out the mobility impaired for special treatment Lifts and special ramps cause delays which reduce the reliability of the service while isolating the mobility impaired from other passengers Mechanical devices such as lifts can also fail and put a train out of
181. tion time dwell time and operating margin capacity is then based only on train length and loading level The existing loading levels on North American rail transit vary from the relaxed seating on many commuter rail lines to the denser loadings experienced on older subway and light rail systems These loadings offer levels of passenger comfort that are inappropriate for new systems intended to compete with the automobile The next section reviews existing rail transit loading standards The remainder of the chapter determines a range of loading standards that can be applied in specific circumstances for each mode LOADING STANDARDS Most rail transit systems have loading standards for the peak hour peak point location with more relaxed standards away from entry into the city center and for off peak times Exhibit 3 21 shows loading standards over the peak 15 minutes for selected heavy rail systems Exhibit 3 21 Passenger Space on Selected North American Heavy Rail Systems iii y llOO UUUtUOOM l Passenger Space based on Gross Floor Space l System City p m f p NYCT New York 2 6 into CBD 4 0 into CBD CTA Chicago 1 5 into CBD 7 0 into CBD SEPTA Philadelphia 1 3 into CBD 8 0 into CBD MBTA Boston 2 0 into CBD 5 0 into CBD BART San Francisco 1 2 1 9 9 0 5 75 WMATA Washington 0 9 2 0 12 0 5 0 MARTA Atlanta 1 4 1 6 7 5 6 75 TTC Toronto 1 8 2 4 6 0 4 5 STC
182. tions can be calculated using the equations presented later in this chapter Variability due to traffic congestion has been reduced as a factor as almost all recently built on street light rail lines operate on reserved lanes A number of older systems still have extensive operation in mixed traffic and so are subjected to the fluctuation in train throughput this causes by reducing g the effective green time for trains Traffic queuing left turns and parallel parking can all serve to reduce light rail transit capacity Signal pre emption allows the light rail train to extend an existing green phase or speed the arrival of the next one Depending on the frequency of intersections and traffic congestion this can have a substantial impact on the flow of general traffic in the area As a result signal pre emption in congested areas is often limited in its scope so as not to have too negative an effect on other traffic The degree to which local politicians and traffic engineers will tolerate the effects of pre emption plays a large role in determining the effectiveness of signal pre emption schemes Signal progression has supplanted pre emption in many cases where light rail trains operate in congested downtown areas This technique gives trains leaving stations a green window during which they can depart and travel to the next station on successive green lights The benefits of progression increase with greater station spacing as less accumulated t
183. tions on this segment timetables only provide departure times and so do not include the dwell time at the first Center City station Another North American example of a downtown commuter rail station where commuter trains run through is Toronto s Union Station Dwells are less critical for commuter rail than for heavy rail transit Platform level and commuter rail car door layout Part 3 RAIL TRANSIT CAPACITY Page 3 79 Chapter 8 Commuter Rail Capacity Transit Capacity and Quality of Service Manual Constant train length Variable train length Seats per unit of train length and short trains Characteristics of existing commuter rail cars Part 3 RAIL TRANSIT CAPACITY TRAIN CAPACITY Except for a few situations where standing passengers are accepted for short distances into the city center commuter rail train capacity is based solely on the number of seats provided on each train A peak hour factor of 0 90 or 0 95 is used Where the equipment design is known the best procedure is to add the number of seats in a train Unless there is an agency policy of peak hour occupancy at 95 of total seats the 0 90 factor should be used Where trains are the same length the commuter rail capacity is simply trains per hour x seats per train x 0 90 Equation 3 19 In many cases train length is adjusted according to demand The longest train will be the one arriving just before the main business starting time in the morning and
184. to 40 trains an hour 90 second headways Ten of these trains one every 6 minutes will remain short to serve the office complex These ten trains have an estimated capacity of 150 passengers each with a higher proportion of sports fans standing The remaining 30 trains must carry 5 700 passengers an hour 7 200 10 x 150 This is 5 700 30 or 190 passengers per train Because of the high number of seats capacity only averages 75 passengers and three car trains would be required to meet the demand In Chapter 9 it was stated that off line stations permit headways that are partly independent of station dwell time with throughput that of the control system minimum train separation plus an allowance for switch operation lock and clearance and a reduced operating margin Exhibit 3 58 shows that a moving block signaling system with 25 meter long trains has a minimum train separation of 13 4 seconds Allowing an operating allowance for merging trains of 45 seconds and rounding up should permit headways down to 60 seconds 60 trains per hour In this case the demand of 7 200 passengers per hour with 150 passengers per train can be met by 48 trains well within the 60 train maximum Off line stations would permit trains to operate directly from each arena station to the It is not always economic to meet heavy rail station However economics enter the picture It is unlikely that the developer occasional peak demands with rail would be willi
185. ts of ADA and the move to level boarding with low floor cars or mini high and profiled platforms should sufficiently improve boarding and alighting movements to offset any negative impact of wheelchair use Part 3 RAIL TRANSIT CAPACITY Page 3 46 Chapter 5 Operating Issues Transit Capacity and Quality of Service Manual 6 GRADE SEPARATED SYSTEMS CAPACITY INTRODUCTION The preceding four chapters have developed the methodologies for each of the components in calculating rail transit capacity This chapter brings these methodologies together for the principal category of grade separated rail which accounts for almost 8096 of rail transit passenger trips in North America Grade separated rail transit is operated by electrically propelled multiple unit trains on fully segregated signaled double track right of way This category encompasses all heavy rail transit all automated guideway transit some of the heaviest volume commuter rail lines and sections of most light rail systems Light rail operates in a variety of rights of way each of which has specific achievable Light rail transit capacities Chapter 7 Light Rail Capacity contains the procedures to determine capacity for light rail operating on other than double track grade separated sections Single track sections if present are usually the capacity limitation However these are rare and achievable capacity is usually controlled by the signaling throughput of grade separated
186. up capacity depends on interior arrangements type of system old or new and time of peak loading Car Capacity There are two approaches to the calculation and evaluation of car capacity design specific and a generic average based on car length Design Specific Capacity If a specific car design has already been chosen capacity calculation is relatively straightforward Space used for seats cabs wheelchair stroller or bicycle positions baggage racks stepwells and other equipment is deducted from the interior floor area and the remaining standing space assigned an appropriate standing density Train Length Alternative This alternative offers the simplest method of establishing capacity per unit of car length based on policy decisions of seating type and quantity and standing density This method is developed and charts provided to determine capacity in Chapter 4 Passenger Loading Levels Train Capacity Design train capacity is simply the product of car capacity and the number of cars per train The number of cars is limited by platform length or for light rail with on street operation by the shortest city block length Part 3 RAIL TRANSIT CAPACITY Page 3 7 Chapter 1 Rail Capacity Basics Transit Capacity and Quality of Service Manual Loading variation within a Achievable capacity is affected by variations in loading along the train train loading train affects system diversity Existing loading diversities ar
187. utes as they reflect human perception and behavior as well as site specific differences expectations cultural attitudes and the transportation alternatives This manual has derived these factors from observation of existing U S and Canadian rail rapid transit operations to create a single diversity or peak hour factor Chapter 4 Passenger Loading Levels details existing peak hour factors and recommends factors for new systems Service Headway Design minimum train operating headway is a function of e signaling system type and characteristics including block lengths and separation operating speed at station approaches and exits or other bottlenecks such as junctions and e train length and station dwells Chapter 2 Train Control and Signaling compares signaling and train control systems Achievable headway must account for additional factors that can affect the separation of individual trains These include differences in operator and rolling stock performance external factors such as grade crossings that can impose delays and the need for schedule recovery time Station dwells combine with minimum operating headway to create a constraining headway bottleneck in the system Typically this is a concern on fully segregated systems that are operating long trains on close headways Busy stations especially major passenger interchanges can produce block occupancy times that limit the entire system Part 3 RAIL TRANSIT CAPACIT
188. vation of crossing gates and signals at near side stations can be reduced using wayside communication equipment This can be done with the operator being equipped with a control to manually start the crossing cycle before leaving the station or by an automatic method An example of the latter approach can be found on the San Diego Trolley The trolley shares some of its track with freight trains and uses a communication device that identifies light rail trains to crossing circuits located on the far side of stations If the crossing controller identifies a train as a light rail train a delay to allow for station dwell time is added before the crossing is activated This ensures that the crossing remains open for cross traffic for most of the time that the light rail train is stopped in the station If the controller cannot identify the train as a light rail train it assumes the train is a freight and activates the crossing gates without delay Other systems use an inductive link between the light rail train and wayside to activate signal pre emption switches and in the future ADA mandated information requirements The most common methods are the Philips Vetag and SEL systems The lowest cost detection approach is the classic overhead contractor Trolleybus technology using radio signals from the power collection pick up to coils suspended on the overhead wires is also applicable to light rail but is not used in North America TRAIN LENGTH AND STATI
189. with light rail service can constrain capacity With care such services can interact harmoniously but once established it may be difficult to remove a heritage service with popular and tourist appeal if and when that capacity is needed for the principal light rail service s Determining On Street Capacity Single streetcars in classic mixed operation can be treated as similar to buses and capacity determined from the procedures of Part 2 of this manual Where as is often the case light rail train lengths approach the downtown block lengths then the throughput is simply one train per traffic signal cycle provided the track area is restricted from other traffic When other traffic such as queuing left turning vehicles prevents a train from occupying a full block throughput drops as not every train can proceed upon receiving a green signal A common rule of thumb is that the minimum sustainable headway is double the longest traffic signal cycle on the at grade portions of the line Equation 3 18 can be used to determine the minimum headway between trains operating on street te g C ta Zacta h max g C 2C ux Equation 3 18 where hos minimum on street section train headway s g effective green time s reflecting the reductive effects of on street parking and pedestrian movements mixed traffic operation only as well as any impacts of traffic signal pre emption C cycle length s at the stop with the highest
190. y under line of sight operating practice at lower speeds Full capacity may be restored but additional trains and drivers will be required to compensate for the slower speeds and waiting time while trains accumulate to form a platoon Wrong side or wrong way working over line sections with grade crossings on on street track can be confusing to motorists and pedestrians and can be hazardous As a result many light rail operators prohibit such operations except where there are no alternatives i e in tunnels or subways Instead their emergency planning calls for a bus bridge around any blockage that is expected to take a significant time to clear All North America light rail operators also have or are affiliated with major bus operations and can expect to obtain buses and drivers for such emergency use on short notice usually by scavenging buses from nearby higher frequency routes The following chart shows the minimum headway for varying single track lengths using the parameters of the above example 3 car trains one passenger stop and 50 km h maximum speed The minimum single track headway is relatively insensitive to train length more sensitive to maximum operating speed and significantly sensitive to the number of stations or stops each additional stop will add 11 2 to 2 minutes T g 12 0 X 100 Oo gt 80 xe S 60 P 4 0 E 2 0 S 0 0 500 1000 1500 2000 2500 3000 Single track length m Part 3

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