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High Frequency Track Circuits

1. uou AA Tad Seula 53 799 sjeu FIGURE A 2 ASSEMBLY OF EQUIPMENT FOR HIGH FREQUENCY TRACK CIRCUITS A 5 SM5865 12 99 Appendix A PARTS LIST UNION SWITCH amp SIGNAL E SCHEMATICS TUNING CAPACITOR MOUNTING BOARD TUNING CAPACITORS AS REQUIRED SEE INSTRUCTION MANUAL FOR PROCEDURE UN451055 1201 46 5 KHZ DWG F451055 SH 12 1202 57 KHZ 1203 715 2 1204 88 KHZ see CHASSIS t GROUND POWER TRANSFORMER Q i 1 1 1 1 t 1 CONVENIENCE LLL VARY _ _ REPLACEMENT FUSE 1 0 SLO BLO 91100301 OUTLET 1 1 i i i 1 1 1 D CIRCUIT SYMBOL TERMINALS ON SCHEMATIC SOLDER LUG FOR FIELD INSTALLED TUNING CAPACITORS 707 SCREW TERMINAL ON EDGE OF PRINTED CIRCUIT BOARD AAR TERMINAL FOR EXTERNAL WIRING ORDERING REFERENCES PART NUMBER FREQUENCY DWG F451147 SH 01 KHZ 4511 47 0103 46 5 4511 47 0107 57 4511 47 0111 71 5 4511 47 0115 89 ALL PART NUMBERS DISPLAYED INCLUDE LIGHTNING ARRESTERS Obsolete Motorola Transistor replaced with Solid State Transistor with higher gain thus requiring R16 Resistor value change FIGURE A 3A TRANSMITTER CIRCUIT DIAGRAM AND PARTS REFERENCE A 6 SM5865 12 99 UNION SWITCH 8 SIGNAL Appendix A PARTS LIST
2. UNION SWITCH amp SIGNAL E Section 1 0 INTRODUCTION 11 GENERAL INFORMATION The US amp S High Frequency Track Circuit is designed to be used where short track circuits are required such as in classification yards to provide switch locking protection Insulated joints are not necessary with this circuit The equipment is completely transistorized and is designed to operate from 117 volt 60 Hz power source Since the track circuits are short the condition of the ballast is not critical More important is the ability to work in areas where there is rail film such as normally found in classification yards Tests with the high frequency circuits have shown no indication of failure to shunt when a heavy grease film mixed with dirt was applied to the rails Track circuits have been employed with lengths of between 60 and 250 feet and no difficulty is foreseen in lengths up to 300 feet A typical high frequency track circuit consists of a transmitter receiver and associated relay connected between two 2 rail to rail shorts which define the limits of the track circuit The transmitter is connected approximately twenty 20 feet from one short with capacitors connected within the unit and on the output terminals to tune that section of the track to the transmitter frequency The receiver is connected approximately twenty 20 feet from the other short with capacitors connected within the unit and on the input terminals to tun
3. 4 2 4 3 Single Switch Track 4 3 4 4 Wi xs eMe qu foli NEN m 4 3 4 5A sudes 4 4 4 5B ein cR 4 4 4 6 Overlapped Circuits mee c 4 5 4 7 Mo nting o cuenten o ntis is Ra a 4 5 4 8 Rail to Rail Shunt Connection 4 8 A 1 Wiring Diagram for High Frequency Track A 4 A 2 Assembly of Equipment for High Frequency Track Circuits A 5 A 3A Transmitter Circuit Diagram and Parts Reference A 6 A 3B Transmitter Circuit Diagram and Parts Reference A 7 4 Receiver Circuit Diagram and Parts A 8 4 Receiver Circuit Diagram and Parts Reference A 9 LIST OF TABLES 4 1 Standard Values for Tuning Circuits ecrire ettet rnnt 4 7 5 1 Transmitter Field 5 2 5 2 Receiver Field nex nba ene 5 3 ii SM5865 12 99
4. 066339 1 4 DN 11 6FB 500 N159871 9077 15 STD PLUG COUPLER N221084 C16749 4 RELAY TIMING RCVR OUTPUT TO RELAY COIL VOLTS 6 1 6 05 6 1 6 05 PICK UP TIME MILLISECONDS 550 560 550 560 DROP AWAY TIME MILLISECONDS 50 55 60 70 COIL RESIST 400 250 400 250 A ca COIL SHUNTED BY TRANSIENT VOLTAGE SUPPRESSOR J723937 HIGH FREQUENCY TRACK CIRCUIT RECEIVER FIGURE A 4A RECEIVER CIRCUIT DIAGRAM AND PARTS REFERENCE SM5865 12 99 SWITCH 8 SIGNAL Appendix A PARTS LIST Dwg F451055 Sh 13 UNIT WITH ARRESTERS SHOWN TUNING CAPACITOR MOUNTING BOARD POWER TRANSFORMER PRI SEC AC POWER SCHEMATIC TUNING CAPACITORS AS REQUIRED ep we et Se RINTEN 7 SEE INSTRUCTION MANUAL FOR PROGEDURE 1454055 1301 4657 KE i 451055 1302 57 kHz 451055 1303 71 5 kHz N451055 1304 89 kHz 1 1 b CHASSIS REPLACEMENT FUSE 25A CONVENIENCE GROUND SLO BLOW PART NO J710077 OUTLET TERMINALS ON SCHEMATIC SOLDER LUG FOR FIELD INSTALLED TUNING CAPACITORS o SCREW TERMINAL ON EDGE OF PRINTED CIRCUIT BOARD TERMINAL FOR EXTERNAL WIRING The US amp S High Frequency Track Circuit is intended for such uses as classification yards car dumpers where a short track circuit with good shunting characteristics with dirty or greasy rail is required Rail to rail sh
5. 4 1 4 2 Track Circuit Connection Arrangements 4 1 4 2 1 General Information 4 1 4 2 2 Typical Track Circuit Illustrations 4 1 4 3 Equipment Mounting 1 4 5 44 Tuning Sensitivity e peo ea pap onec pe tede vnus actenus 4 6 5 0 FIELD INSPECTION AND 5 5 1 5 1 Test Equipment and Periodic 5 1 Transmitter Em 5 1 RR 5 1 22 5 2 APPENDIX PARTS 1 Transmitter and Receiver A 1 A 2 Boards ep 1 General T 2 4 Auxiliary 4 5865 12 99 i UNION SWITCH 8 SIGNAL Table of Contents LIST OF FIGURES 1 1 Physical Layout 1 1 1 2 Electrical 0 1 1 3 1 Diagonal Shunt Installation ices 3 3 4 1 Single 4 2 4 2 Dual Circuit with Diagonal Shi oui nuit enti Snnt pa
6. C8605 SH 0101 0117 1 46 5 451055 1301 13 4730805 J709144 0178 0 68 0103 0119 3 46 5 N451055 1201 12 N435551 68 J709144 0078 0 68 0105 0121 1 57 451055 1302 13 4730805 4709144 0078 0 60 0107 0123 3 57 451055 1202 12 435551 68 J709144 0078 0 68 0109 0188 1 71 5 N451055 1303 13 4730805 J709144 0081 0 33 0111 0127 3 71 5 N451055 1203 12 N435551 68 J709144 0081 0 33 0113 0189 11 89 451055 1304 13 J730805 4709144 0082 0 15 0015 0131 13 89 451055 1204 12 N435551 68 J709144 0082 0 15 White Wire to Silver Terminal Black Wire to Final track tuning capacitors Brass Terminal to be installed at time of field installation Receiver Transmitter Circuit Bd Circuit Bd F451035 Sh 12 F451035 Sh 13 when called when called for IF Wired same REQUIRED as Xmtr Track 1 Track 2 Gircuit Bd 2 2 Track 1 Line 2 Relay Line 1 Relay Wiring Diagram FIGURE A 1 WIRING DIAGRAM FOR HIGH FREQUENCY TRACK CIRCUITS SM5865 12 99 Appendix A PARTS LIST 319VLd3234 YAMOd 30 NOIIVIN3IIO 441235 Y uum gt apisul xosdde urbs SuOlSdHHV S IVNIANH3 SHOISJHHV S IVNIWH31I vi 0L 8 8 s
7. 12 99 UNION SWITCH 8 SIGNAL Appendix A PARTS LIST Item Description Part No 210 Plate Name M451 425 9701 215 Receptacle DX J72030 220 SC 6 32 x 3 8 Pan Stp J507262 225 Pipe 1 Galv M26503 230 Screen M435695 235 Bushing 1 Conduit J69677 240 Bolt 1 13 x 3 1 2 Hex J046563 245 Nut gt Hex X Jam Cad P J48016 250 Nut Hex Stl Cap P J48013 255 Washer 1 2 Stl Cad P 447503 260 Washer 6 Lock Stl J047662 265 Tag Bx 110 J75510 0689 270 Tag N x 110 J75510 0080 275 Rag Relay J75510 1157 280 Tag Relay J75510 1158 285 Tag Track 1 J75510 1169 290 Tag Gnd J75510 0566 300 Term 6 Amp J730239 305 Term 12 4 amp J730041 310 Wire 18 Flex Bk A45665 0000 315 Wire 18 Flex W A45665 0009 320 Grommet J751238 325 Scr 20 x 358 Pnh Stl J507263 330 Nut Insulated J48300 335 SC 4 40 x 1 4 Flat Stl Tp J521070 340 Tag Track E J75510 1170 345 Term 10 Amr J730048 350 Initial Tuning Cap See Tab 355 Wire 20 Bare Copper A043180 360 Wire 20 PVC Grn M 258 30 A045505 0004 365 Tubing A774201 370 Wshr 10 Fit Stl J475077 SM5865 12 99 A 3 Appendix A PARTS LIST 4 Auxiliary Tabulation 1 8 5 26 2 Circuit Bd Transformer Initial Tuning 2 5 Capacitor 451147 451055 5
8. 12 99 A 1 Appendix A PARTS LIST General Parts List Item Description Part No 5 Box M374986 10 Cover M347723 15 Elbow 1st St I J32485 20 Gsk Spg 12 x Va A690937 25 Not used Not used 30 SC 3 8 x 1 4 Set Cad P J50577 35 Nut 3 8 Hex Stl Cad P J48009 40 Plate Mounting M451 148 0101 45 SC 4 20 x 7 8 Fil Stp J52202 50 Washer 4 M LK S TP J47775 55 Block Terminal 7 way M225586 60 Block Terminal 3 way M109154 65 Washer J47818 70 Nut M29103 75 Nut M29101 80 Arrester N451552 0101 85 Connector Term M47290 90 Chassis See Aux Tab 95 Transformer See Aux Tab 100 Board Pri Cir See Aux Tab 105 Board Term 4776611 110 Spacer J772336 115 Nut 6 31 Hex Stl Tr J048148 120 Bushing 2 1 x 2 Red J032088 125 Bushing 2 x 1 Red J32054 130 Nut Lock M373656 135 Plastic Cap Plug J703517 140 Plastic Cap Plug J703516 145 Elbow 1 1 4 St M J32486 150 Pipe 1 1 4 M437182 155 Nut 1 4 20 Hex Stl Tp J48002 160 SC 4 40x 5 16 bind Stl Tp 450996 165 Washer 4M Lk S Tp J47765 170 Washer 4 Plate S Tp J47640 175 SC 8 32 x 1 2 Bind Stl Tp 450992 180 Washer 8M Lk Tp J47681 185 Washer 8 plate S Tp J47745 190 Spacer M485696 195 SC 8 23 x 3 8 Bind Stl Tp J507235 200 SC 2 x Rd Type U Drive Sc Tp J52648 205 Nut 8 32 Hex Stl Tp J48166 A 2 SM5865
9. DIMENSIONS VENTILATOR POSITION OF PRINTED CIRCUIT BOARD ABOVE CHASSIS TUNING CAPACITOR MOUNTING BOARD PEDESTAL CHASSIS GROUND SCREW ScHASsIS MOUNTED TERMINALS WITHIN CAST SEE BELOW IRON BOX SQ IN INSIDE AREA UNDERGROUND CABLE ENTRANCE The US amp S High Frequency Track Circuit is intended for such uses as classification yards car dumpers etc where a short track circuit with qood shunting characteristics with dirty or greasy rail is required Rail to rail shunts define track circuit limits without insulated joints HUNT RAILTORAIL TYPICAL TRACK CIRCUIT CONFIGURATION RAILTORAL TWISTED 3 TURNS FOQT TRANSMITTER CAN BE REDUCED 16 FOR SPECIAL 20 20 250 20 APPLICATIONS REQUIREMENTS FOR SHUNT WIRES 2 SEPARATE WIRES OF AT LEAST AWG 6 INSULATED SPACED MINIMLIM OF 5 APART A COMMON POINT OF CONNECTION TO THE RAIL MAY BE USED BOND WIRES HEAVY GAUGE RAILHEAD TYPE PREFERRED WELDED OR SWAGED SECURELY TO RAILHEAD TRAGK LEADS AWG 6 INSULATED TWISTED 3 TURNS FT TO BE AS SHORT AS POSSIBLE SEE INSTRUCTION PAMPHLET U 5865 FOR ADDITIONAL DETAILS NOTE NO OTHER OF TRACK CIRCUIT CAN BE SUPERIMPOSED ON THE HIGH FREQUENCY CIRCUIT 3 MAXIMUM AAR TERMINAL BOARD TRANSMITTER SPECIFICATIONS WEIGHT COMPLETE 75 LBS INPUT POWER 120 V 10 60 HZ 15 WATTS OUTPUT APPROX 35 V PEAK TO PEAK AT SPECIFIED FREQUENCY UNITS WITH PULSED AS SHOWN
10. LIGHTNING ARRESTERS 40VDC 10 BN SPARE CHASSIS GROUND SCREW P 10 SIGNAL 2M5 8 MS 2M5 10 10 10 FIGURE A 3B TRANSMITTER CIRCUIT DIAGRAM AND PARTS REFERENCE SM5865 12 99 A 7 Appendix A PARTS LIST UNION SWITCH amp SIGNAL VENTILATOR 35 1 8 9 1 2 SQ IN INSIDE AREA UNDERGROUND CABLE ENTRANCE ORDERING REFERENCES PART NUMBER DWG F451147 SH 01 N451147 0101 FREQUENCY KHZ 46 5 N451147 0105 N451147 0109 N451147 0113 57 115 89 ALL PART NUMBERS DISPLAYED INCLUDE LIGHTNING ARRESTERS RECEIVER SPECIFICATIONS WEIGHT COMPLETE 75 LBS INPUT POWER 120 V 10 60 HZ 3 WATTS OUTPUT SEE RELAY TIMING CHART BELOW RELAY PN 150B N322500 901 PN250B N322554 901 OR 902 PN150B N3225900 901 PN 250B N322554 901 OR 902 DIMENSIONS POSITION OF PRINTED CIRCUIT BOARD ABOVE CHASSIS TUNING CAPACITOR MOUNTING BOARD CABLE 7 ENTRANCE FITTING FOR TRACK LEADS POWER CHASSIS GROUND SCREW TRANSFORMER AAR TERMINALS SEE BELOW CHASSIS MOUNTED WITHIN CAST IRON BOX AAR TERMINAL BOARD TRACK 1 SPARE TRACK 2 UNITS WITH LIGHTNING ARRESTORS UNITS WITHOUT LIGHTNING ARRESTORS 1 2 RECOMMENDED RELAYS 1 150 6 400 7 N322500 901 D66000 3 BASE N334266 066002 1 2 PN250B 6FB 8F 3B 250 N322554 901 D66334 14 BASE N373979 066339 1 3 PN250B 8FB 4F 2B 250 f N322554 902 D66334 14 BASE N434650
11. input circuit and a transmitter of another frequency can be operated directly across the receiver inputs without causing false operation SM5865 12 99 2 1 Section 2 0 OPERATION This page is intentionally blank 8 2 SM5865 12 99 Section 3 0 DESCRIPTION 3 1 Transmitter The transmitter consists of a printed circuit board containing a rectifier to convert the power supply to DC an RF oscillator a timing multivibrator which controls the transmitter ON OFF duty cycle a single ended Class B power amplifier a power transformer which converts the 117 volts 60 Hz supply voltage to 32 volts and e aseparate board with solder terminals for mounting capacitors to tune the track An AAR terminal strip provides for external connections to the track the supply voltage and the case ground Provisions are included for mounting lightning arresters in installations where they are required A complete unit can be furnished with or without arresters All of this is contained in a weatherproof box that is mounted near the rails so that the track lead to the nearest rail is no longer than three feet The supply voltage leads enter the box through the bottom while the track leads enter through a weatherproof fitting on the end nearest the rails The transmitter output amplifier is capable of driving a minimum ballast impedance of 2 ohms 1000 ft The timing and Q of the track will determine the load impedanc
12. of track from the transistor oscillator and power amplifier that form the transmitter The energy is coupled through the rails into the tuned section of track at the receiver input These bursts of energy are of approximately two millisecond duration with approximately eight milliseconds between bursts The input circuit of the receiver transformer couples this energy into a bridge rectifier which converts the high frequency energy into square pulses of two millisecond duration with eight milliseconds between pulses When these pulses are of sufficient amplitude to trigger the fail safe peak detector a separate frequency of approximately 220 kHz is generated in the receiver This signal is amplified detected and converted into a D C control voltage to energize the relay As long as the amplitude of the input triggers the peak detector the relay will be held energized The relay will drop out from failure of input power to either the receiver or transmitter from loss of connections to the rails or from normal shunting of the track by a car This will de tune and short either the output of the transmitter or input to the receiver or both depending on the position of the wheels within the limits of the track circuit Because of the rail to rail shorts which define the limits of the track circuit it is virtually impossible to get interference from adjacent circuits Also the receiver input is very selective with its high parallel resonant
13. receiver and tune the receiver end For diagonal shunt arrangements with two circuits adjacent to each other tune the low frequency unit first with the high frequency circuit open circuited with the low frequency circuit intact and tuned After the tuning capacitors have been installed proceed with the sensitivity adjustment as follows a Connect an oscilloscope across the receiver input terminal b Connect a DC voltmeter set on the 10 volt range across the relay terminals A 400 ohm relay or resistor should be connected to the terminals for proper loading c Connect a rail to rail shunt on the rail midway between the receiver track connections and the receiver rail to rail short The rail to rail shunt wire should be at least 446 AWG and not longer than seven feet See Figure 4 8 SM5865 12 99 4 7 FIGURE 4 8 RAIL TO RAIL SHUNT CONNECTION Note The location of the shunt in the center of the shunt zone as shown in Figure 4 8 will satisfy most applications However in congested areas where there is an abundance of steel traversing between the rails in the shunt zone a shift of four or five feet of the shunt location closer to the receiver might be necessary to properly adjust the track circuit d Set the sensitivity control on the receiver for a reading of 1 9 1 volt DC on the multimeter Loosen the south end of the rail to rail shunt and connect to point Verify that the
14. to 20 percent at resonance in a straight track circuit and nearly 100 percent when one is on straight track and the other at a diagonal shunt Remove the resistor and recheck the tuning before proceeding The amplitude of the signal at the transmitter may be between 50 and 80 volts peak to peak while at the receiver it may be between 50 and 150 volts peak to peak When the capacitance value has been determined remove the decade box and solder fixed capacitors to the terminal board provided in each enclosure equal to the decade setting In every case choose capacitors that are equal to or slightly less than the decade setting never larger 4 6 SM5865 12 99 Section 4 0 APPLICATION AND INSTALLATION The following standard values should provide enough combinations to satisfactorily tune all circuits TABLE 4 1 STANDARD VALUES FOR TUNING CIRCUITS 015 MFD 10 200 volt J709144 0076 047 MFD 10 200 volt J709144 0075 10 MFD 10 200 volt J709144 0083 15 MFD 10 200 volt J709144 0082 33 MFD 10 200 volt J709144 0081 47 MFD 10 200 volt J709144 0080 56 MFD 10 200 volt J709144 0079 68 MFD 10 200 volt J709144 0078 1 0 MFD 10 200 volt J709144 0077 NOTES On track circuits longer than 100 tuning should be done by first shorting the receiver track terminals and then adjusting the transmitter decade box for maximum signal Finally remove the short from the
15. voltage level increases f Move the south end of the rail to rail shunt from point to point b Verify that the voltage level decreases g Remove the shunt The voltage should rise to 5 8 3 volts DC The circuit is now ready for operation 4 8 SM5865 12 99 Section 5 0 FIELD INSPECTION AND SERVICING Regularly scheduled maintenance for any type of equipment is the best way to assure reliable operation for a long period of time Therefore the following information is given to assist in establishing some form of periodic inspection and test 5 1 TEST EQUIPMENT AND PERIODIC INSPECTION For a quick simple check of the equipment s general condition all that is needed is an analyzer similar to a Simpson Model 260 The periodic test should consist of the following checks 5 1 1 Transmitter Visibly inspect for moisture damage and component discoloration from overheating Refer to Figure A 3 for transmitter circuit and parts reference Note the following voltages a Line voltage 117 volts 10 60 Hz b Power input to board 32 volts 10 60 Hz c DC across C8 40 volts 10 d DC across C1 26 volts 10 X Output 2 5 volts RMS minimum This low voltage reading is the result of a 2096 duty cycle pulse operation Continuous operation of the transmitter output would give a reading approximately five times as high 5 1 2 RECEIVER Visibly inspect for moisture damage and component
16. M5865 12 99 5 3 Section 5 0 FIELD INSPECTION AND SERVICING This page is intentionally blank 5 4 SM5865 12 99 Appendix A PARTS LIST The parts list that follows is a tabulation of the parts that may be necessary to maintain this equipment These parts may be ordered directly from Union Switch amp Signal Inc A 1 Transmitter and Receiver Assemblies Part No Part No Description Complete less Pedestal Transmitter Assembly with Arrestor 46 5 kHz Transmitter 57 kHz Transmitter 71 5 kHz Transmitter 89 kHz Transmitter Receiver Assembly with Arrestor 46 5 kHz Receiver 57 kHz Receiver 71 5 kHz Receiver 89 kHz Receiver A 2 Circuit Boards 451147 0135 451147 0103 451147 0139 451147 0107 451147 0143 451147 0111 451147 0147 451147 0115 451147 0133 451147 0101 451147 0137 451147 0105 451147 0141 451147 0109 451147 0145 451147 0113 Circuit Boards for Transmitters 46 5 kHz Transmitter N451055 1201 57 kHz Transmitter N451055 1202 71 5 kHz Transmitter N451055 1203 89 kHz Transmitter N451055 1204 Circuit Boards for Receivers 46 5 kHz Receiver N451055 1301 57 kHz Receiver N451055 1302 71 5 kHz Receiver N451055 1303 89 kHz Receiver N451055 1304 Complete Assemblies include Pedestal SM5865
17. OVERLAPPED CIRCUITS 4 3 EQUIPMENT MOUNTING DATA A transmitter or receiver basic housing consists of a cast iron box M374986 with cover M347723 and a pedestal M224650 which are shipped separately The unit is mounted near the rails with the pedestal buried in the ground so that the bottom of the box is two to four inches above the ground The length of the track lead to the nearest rail shall be no longer than three feet see Figure 4 7 The 117 volt 60 Hz power lead and the relay control wires are brought through a special opening in the pedestal and through the bottom of the box The track leads are brought through the end of the box nearest the rails The terminals on the AAR terminal strip are identified for convenience in wiring all external connections A second solder type terminal strip is provided to mount the tuning capacitors required to resonate that section of track between the track lead connections and the rail to rail short SOIL LINE BALLAST RELAY LEADS RECEIVER ONLY FIGURE 4 7 MOUNTING EQUIPMENT SM5865 12 99 4 5 Section 4 0 APPLICATION AND INSTALLATION 4 4 TUNING AND SENSITIVITY ADJUSTMENTS Proper tuning of the track is most easily accomplished by using an oscilloscope and a decade capacitor box A fixed capacitor has been installed on the track lead terminal strip Additional capacitors must be installed during installation to fine tune the track These capacitors will be in parallel wi
18. RIPTION This page is intentionally blank 3 4 SM5865 12 99 Section 4 0 APPLICATION AND INSTALLATION 4 1 FREQUENCY SELECTION There are four frequencies available 46 5 57 71 5 and 89 kHz To assure that two track circuits operating on the same frequency do not interfere with each other the following rules shall be observed 1 4 Do not install track circuits directly parallel to each other on adjacent tracks unless the operating frequencies are different Where there are three or more tracks in parallel every other track may have the same frequency Do not install track circuits of the same frequency along the same track unless a track circuit of a different frequency separates them Where two track circuits are to be installed with a diagonal rail to rail short between them to provide overlap of the two circuits only the lowest and highest frequency available are to be used This is presently 46 5 kHz for the lowest and 89 kHz for the highest In long track circuits apply the lowest frequency available 4 2 TRACK CIRCUIT CONNECTION ARRANGEMENTS 4 2 1 General Information The frequency allotted for each circuit shall be determined from the rules given in Section 4 1 Frequency Selection Railhead bonds shall be used on all rail joints and all other joints shall be bonded as short as possible depending on track hardware conditions 4 2 2 Typical Track Circuit Illustrations The following ill
19. UNION SWITCH amp SIGNAL 645 Russell St Service Manual 5865 Batesburg SC 29006 High Frequency Track Circuits Installation and Maintenance December 1999 An ANSALDO Signal Company 1999 Union Switch amp Signal Inc Printed in USA UNION SWITCH amp SIGNAL Revision Index Date of Revision August 1980 December 1999 SM5865 12 99 i UNION SWITCH amp SIGNAL Table of Contents SECTION TOPIC PAGE 1 0 GENERAL INFORMATION Dai ona t 1 1 1 1 INTRODUC MON c P 11 1 2 TEAM AND TECHNICAL 5 1 2 20 sits uus uU REM 2 1 21 High Frequency Track Circuit 2 1 30 DESCRIPTION 3 1 3 1 3 1 3 3 Associated cee ca eee cee Sc voce psionic 3 2 3 3 1 Track Connections BOTH iuo et Rex suat ting 3 2 3 3 2 ACD 3 2 3 93 Lightning tnr nor one 3 2 4 0 APPLICATION AND INSTALLATION 4 1 41 Freguency SeleoblOll etti tnit
20. discoloration from overheating Refer to Figure A 4 for receiver circuit and parts reference a Line voltage 117 volts 10 60 Hz b Power input to board 25 2 volts 10 60 Hz c DC across C16 volts 10 d Relay voltage 5 8 volts DC 3 volts Input from track 2 5 volts minimum This is the RMS reading of the 2096 duty cycle of the transmitted pulse If the reading is between 12 and 20 volts RMS the transmitter is in continuous transmission instead of pulse SM5865 12 99 5 1 Section 5 0 FIELD INSPECTION AND SERVICING The historical record of several inspections provides a means of determining when a unit is about to fail because a consistently repeated reading establishes the proper operating reference Therefore when a particular reading begins to change from one inspection to another this can be interpreted as an approaching failure in that unit 5 2 FIELD SERVICING In the event that actual failure occurs the voltage checks of the periodic inspection will provide enough information to determine where the failure has occurred Interpretation of readings is shown on the following troubleshooting tables TABLE 5 1 TRANSMITTER FIELD SERVICING INDICATION CORRECTIVE ACTION 1 No line voltage Check power distribution system and cabling 2 Low line voltage when Check transformer for shorted turns or shorts on circuit is connected the printed circuit board Replace trans
21. e seen by the transmitter with very little effect from the ballast since the track circuit is short Typical load impedance of twelve ohms would permit peak output power during the pulse of approximately fifty watts The efficiency of the circuit is very high due to Class B operation and low duty cycle The available frequencies for operation are 46 5 kHz 57 kHz 71 5 kHz and 89 kHz 3 2 Receiver The receiver consists of a printed circuit board containing all the circuitry necessary to convert the R F signal received from the track to a DC voltage to operate a 400 ohm relay e a power transformer to change the 117 volts 60 Hz supply voltage to 25 2 volts 60 Hz and e separate board with solder terminals for mounting capacitors to tune the track An AAR terminal strip provides for external connections to the track supply voltage and relay Provisions are included for mounting lightning arresters in installations where they are needed All of this is contained in a weatherproof box which is mounted near the rails so that the track lead to the nearest rail is no longer than three 3 feet The supply voltage and relay leads will enter the box through the bottom while the track leads will be brought through a weatherproof fitting on the end towards the rails SM5865 12 99 3 1 Section 3 0 DESCRIPTION UNION SWITCH amp SIGNAL 3 3 ASSOCIATED HARDWARE 3 3 1 Track Connections and Rail Bonds The track conn
22. e that section of the track to the transmitted frequency Electrically this makes the enclosed section of track look like two tuned circuits coupled in parallel with the inductance of the untuned section of track in series See Figures 1 1 and 1 2 TRANSMITTER RECEIVER CAPACITORS CAPACITORS 117 117 60Hz TRANS 60 Hz FIGURE 1 1 PHYSICAL LAYOUT FIGURE 1 2 ELECTRICAL EQUIVALENT SM5865 12 99 1 1 Section 1 0 INTRODUCTION The equipment is contained within a weatherproof case that is pedestal mounted on the wayside at 3 feet from the nearest rail Power input track and relay output connections are made to an AAR terminal strip mounted internally The receiver relay is external and can be located where convenient up to several thousand feet away from the receiver 1 2 R A I L TEAM AND TECHNICAL SUPPORT The Rapid Action Information Link R A I L Team is comprised of a group of experienced product and application engineers ready to assist and resolve any technical issues concerning any US amp S product Any questions regarding the contents of this Service Manual can be answered by contacting R A I L Team toll free at 800 652 7276 or via e mail railteam switch com 1 2 SM5865 12 99 Section 2 0 OPERATION 2 1 High Frequency Track Circuit Function The High Frequency Track Circuit functions by applying bursts of high frequency energy into the tuned section
23. ections rail bonds and rail to rail shorts must be very securely fastened and properly located or the track circuit cannot function properly Any loosening breaking or shifting of connections can change the tuning or completely disable the system All track leads should be AWG 6 insulated stranded wire or equivalent insulated bond wire These leads should be twisted at least three twists per foot between the nearest rail and the transmitter or receiver mounting box The lead to the far rail must be as short as possible The rail to rail shorts consist of two leads of the same wire as the track leads and spaced a minimum of five inches apart with staples driven into the ties The ends must be securely bolted or welded to the web of the rails All rail bonds must be heavy gauge railhead type either welded or swaged securely into the rail for best operation Longer bonds may be used where rail hardware makes it necessary but the railhead type is preferred and should be used whenever possible In applications where two track circuits are in series and a sharp transfer from one circuit to the other is required a diagonal shunt must be installed in a ten foot section of track This diagonal must be made of three leads equivalent to the track leads These may be connected at one point on each rail but the leads must be spaced a minimum of five inches apart and stapled to the ties between the rails The receiver of one circuit is connected a
24. former or printed circuit board 3 Low DC voltages a Check tracks and track leads for shorts b Check to see that tuning capacitors are not broken loose or defective Detuned circuit loads DC supply c Replace printed circuit board if a and b are good 4 Low output Same as step three 3 5 High output Replace printed circuit board as timing multivibrator circuit is defective allowing transmitter to operate continuously 5 2 SM5865 12 99 Section 4 0 APPLICATION AND INSTALLATION TABLE 5 2 RECEIVER FIELD SERVICING INDICATION CORRECTIVE ACTION 1 No line voltage Check power distribution system and cabling 2 Low line voltage when circuit is connected Check transformer for shorted turns or shorts on the printed circuit board Replace defective part Low DC voltage If line voltage is good check for a short circuit in output to relay or low relay voltage Replace board 4 Norelay voltage Check for signal on input terminals If input from track is low or too high trouble is in track or transmitter NOTE If input RMS voltage is greater than 12 V RMS the transmitter is operating continuously and the receiver cannot respond to a continuous input 5 Noinput Check all track leads and rail connections for opens or shorts Check transmitter output Repair track leads or replace transmitter as required S
25. onnections for transmitter or receiver shall be made to the fixed rail Shunt zone Maximum variation of shunting point will fall between the limits shown SHUNT ZONE h 4 4 20 lt lt 20 to 260 a FIGURE 4 1 SiNGLE TRACK CIRCUIT SHUNT ZONE WITH OVERLAP h 21 2 _ 20 100 10 35 10100 FIGURE 4 2 DUAL CIRCUIT WITH DIAGONAL SHUNT 4 2 SM5865 12 99 Section 4 0 APPLICATION AND INSTALLATION SW PTS 1 20 to 100 1 FIGURE 4 3 SINGLE SWITCH TRACK CIRCUIT 20 TO 100 Sw FIGURE 4 4 LAP SWITCH TRACK CIRCUIT SM5865 12 99 4 3 WHEN A IS 110 OR LESS MAY BE REDUCED TO 16 WHERE IT IS NECESSARY TO KEEP EFFECTIVE LENGTH OF TRACK CIRCUIT AS CLOSE TO 5 10 5 DISTANCE AS POSSIBLE FOR CIRCUITS OVER 110 MUST REMAIN AT 20 FIGURE 4 5A SHORT CIRCUITS FIGURE 4 5B SHORT CIRCUITS Where space requirements necessitate such as close coupled switches shown dotted two circuits may be overlapped as shown Each circuit will shunt independently A1 need not equal A2 although all dimensions are subject to the length limitations as shown in Figure 4 5A The transmitters can be staggered if required as shown in Figure 4 5B 4 4 SM5865 12 99 Section 4 0 APPLICATION AND INSTALLATION M EACH CIRCUIT SHUNTS INDEPENDENTLY FIGURE 4 6
26. t one end of the diagonal shunt and the receiver or transmitter of the other circuit is connected at the other end of the diagonal shunt See Figure 3 1 for further information refer to Section 4 0 Application and Installation Data 3 3 2 Receiver Relay The receiver is designed to operate a relay with a 400 ohm coil typically the PN 150B N322500 001 or PN 50B N292701 The pick up voltage is normally 5 3 volts DC and the drop away 1 9 volts DC The current at 5 3 volts is only 0132 ampere therefore the relay can be located several thousand feet from the receiver and still be operational 3 3 3 Lightning Protection Provision has been included for mounting a Style USG Arrester N314265 from each track lead to ground in both the receiver and transmitter Actual installation of the arresters is required when the particular track circuit is isolated from others or when it is the first or last of a number of track circuits along a section of track 3 2 5865 12 99 Section 3 0 DESCRIPTION UNION SWITCH amp SIGNAL These arresters permit a maximum of 300 volts before breakdown The pedestal that the equipment is mounted on provides grounding for the arresters However in areas where poor ground conductivity is experienced conventional ground rods may be used with the arresters connected to the pedestal the ground rod or both FIGURE 3 1 DIAGONAL SHUNT INSTALLATION SM5865 12 99 3 3 Section 3 0 DESC
27. th the fixed capacitor Before any AC power is connected to the transmitter connect a decade capacity box to the track lead and set it to 1 MFD to tune the track Then turn on the power and reduce the decade box setting until a maximum signal is obtained across the terminal as discussed below After tuning fixed capacitors equal to the final setting of the decade box are then installed The range of capacitance required to tune a track circuit will vary from approximately 33 MFD for the highest frequency to approximately 2 0 MFD for the lowest frequency depending on the installation arrangement In most cases the track circuit will be short enough that it will be best to tune the transmitter and receiver simultaneously or at least back and forth until the maximum signal is obtained To tune the transmitter it is best to connect an oscilloscope at the rail connections and the decade box at the track connections inside the transmitter enclosure To tune the receiver it is best to connect both the oscilloscope and decade box at the track connections inside the receiver enclosure Temporarily connect a non inductive 10 ohm 50 watt resistor in series with one lead of the transmitter Adjust the decade capacitor boxes in equal steps at both the transmitter and receiver until resonance is obtained in both circuits This is indicated by obtaining a maximum signal on the scope Note The capacitance at the receiver and transmitter may differ 10
28. unts define track circuit limits without insulated joints TYPICAL TRACK CIRCUIT CONFIGURATION TWISTED 3 TURNS FOOT RAIL TO RAIL SHUNT C2 c3 c4 5 7 ce c9 11 C10 15 C12 13 14 C16 01 2 3 4 6 7 5 08 8 10 12 3 MAXIMUM 1 RECEIVER TRANSMITTER CAN BE REDUCED TO 16 FOR SPECIAL APPLICATIONS gl TO 20 NOTE No other type of track circuit can be superimposed on the high frequency circuit MAXIMUM DISTANCE RECEIVER TO RELAY CIRCUIT SYMBOL Wire Size 6 9 12 14 TRACK CIRCUIT 250 OHM 5250 2625 1300 825 400 7650 3825 1900 1200 HIGH FREQUENCY TRACK CIRCUIT RECEIVER FIGURE 4 RECEIVER CIRCUIT DIAGRAM AND PARTS REFERENCE 047 MF 37 250 PF 820 PF 10000 PF 1500 PF 8200 PF 5100 PF 100 250 1N456 1N959B 1N4003 1 752 680 MH 68 2N4037 2N3643 2N2270 2N3440 100 1500 LEGEND TYPENALUE SM5865 12 99 A 9 Appendix A PARTS LIST This page is intentionally blank A 10 SM5865 12 99
29. ustrated track circuit arrangements shown in Figures 4 1 through 4 6 are given as examples that should provide sufficient information for proper installation of these track connections as well as any not specifically given The letters shown in parenthesis on each illustration indicate the applicable note from the following list a Rail to rail short Consists of two AWG 6 stranded copper insulated wire or equivalent separated a minimum of five inches The wire is stapled to the tie and securely attached to the web of the rail either at a common point connection or at two separate points while maintaining the five inch separation b Track leads The leads to the transmitter and receiver must be twisted three twists per foot from the nearest rail to the unit housing and the distance to the nearest rail must be three feet or less SM5865 12 99 4 1 Section 4 0 APPLICATION AND INSTALLATION UNION SWITCH amp SIGNAL Where presence detectors are used the detector loop must be located between the transmitter and receiver rail connections as shown Under no circumstances may part of the loop be within a tuned section The diagonal shunt see Figure 3 1 Switch bonding Bonding is necessary around heel blocks and between rails behind the heel block Switch rail to rail shorts The rail to rail shorts must be between the frog and rail connections of transmitter or receiver Switch track leads The rail c

High Frequency Track Circuits

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