US3666217A - Track communication system for continuous rail - Google Patents

Track communication system for continuous rail Download PDF

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Publication number
US3666217A
US3666217A US34235A US3666217DA US3666217A US 3666217 A US3666217 A US 3666217A US 34235 A US34235 A US 34235A US 3666217D A US3666217D A US 3666217DA US 3666217 A US3666217 A US 3666217A
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United States
Prior art keywords
track
control
rails
transmitter
track circuits
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Expired - Lifetime
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US34235A
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English (en)
Inventor
Henry C Sibley
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SPX Technologies Inc
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General Signal Corp
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Publication date
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    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B61—RAILWAYS
    • B61L—GUIDING RAILWAY TRAFFIC; ENSURING THE SAFETY OF RAILWAY TRAFFIC
    • B61L23/00—Control, warning or like safety means along the route or between vehicles or trains
    • B61L23/08—Control, warning or like safety means along the route or between vehicles or trains for controlling traffic in one direction only
    • B61L23/14—Control, warning or like safety means along the route or between vehicles or trains for controlling traffic in one direction only automatically operated
    • B61L23/16—Track circuits specially adapted for section blocking
    • B61L23/168—Track circuits specially adapted for section blocking using coded current

Definitions

  • the improvement comprises train occupancy communication means including a plurality of track transmitters each selectively tuned to one of two transmission frequencies alternately coupled to the rails at spaced intervals representing the center of the track circuits and a plurality of receivers each selectively responsive to the transmitter frequencies coupled to the rails at the ends of each of these track circuits for receiving signals from the associated transmitter.
  • Means coupled to the receiver generates an occupancy signal when the communication is cut off for one transmitter and its associated receiver by a vehicle shunt.
  • Control communication means is also included wherein a plurality of control transmitters are each selectively tuned to one of two transmission frequencies different from the track transmission frequencies and are alternately coupled to the rails at each of the adjacent ends of the first track circuits representing a second set of center fed track circuits.
  • a plurality of receivers again each selectively responsive to the transmitter frequencies are coupled to the rails at the center of each of the second set of track circuits for receiving signals from its associated transmitter.
  • Means coupled to each control receiver generates a control signal in accordance with the control receiver signals.
  • the occupancy communication means and the control communication means both simultaneously are capable of transmitting signals along the layout.
  • a communication system for continuous rail track layouts has 6 Claims, 6 Drawing Figures A A B B B A T A A B B PATETTTEIImso I972 3,6662 1 7 SHEET 2 or 2 I RR 2 HIGH-LOW L FREQUENCY E 25 SHIFT AMP TIMING OSCILLATOR 23 APPARATUS ENCODER RECEIVER (ADDRESS COUPLER APPROPRIATE I 00055) HQ 4 I T T T T T FROM FROM ADJACENT WAYSI DE RECEIVERS DEVICES T ,3 T Y 3
  • the track circuit is generally used to detect the presence of vehicles in selected intervals or blocks of railroad territory. It is also used to communicate information between signal locations and from block ends to moving vehicles.
  • the basic track circuit comprises a pair of track rails isolated as by a set of insulating joints from the rest of the track and having an energy source at one end and a relay connected across the rails to the other, the presence of a vehicle shunting the rails diverts the current from the energy source through the shunt and causes the relay to drop out thus indicating presence of a vehicle in that block or track circuit.
  • a coded communication system for continuous rail layouts including a plurality of center fed track circuits.
  • the improvement comprises train occupancy communication means including a plurality of track transmitters each selectively tuned to one of two transmission frequencies alternately coupled to the rails at spaced intervals, for generating signals in the rails and said intervals represent center of a first set of track circuits.
  • a plurality of occupancy receivers has been provided, each selectively responsive to the transmitter frequencies and said occupancy receivers are coupled to the rails at the ends of each of the first track circuits for receiving signals from its associated transmitter.
  • Means coupled to the occupancy receivers generates an occupancy signal when the communication is cut off from one transmitter and its associated occupancy receiver by a vehicle shunt.
  • Control communication means has also been included comprising a plurality of code transmitters each selectively tuned to one of two transmission frequencies different from the first track transmission frequencies alternately coupled to the rails at each adjoining adjacent ends of the first track circuits for defining a second set of track circuits for generating control signals in the rails.
  • a plurality of control receivers each selec tively responsive to the transmitter frequencies, coupled to the rails at the center of each of the second track circuits are for receiving control signals from its associated transmitter and means coupled to each control receiver generate control signals in accordance with the control receiver signals.
  • the train occupancy communication means and the control communication means both simultaneously are capable of transrnitting signals along said layout.
  • FIG. 1 is a plan view of the communications system of the present invention.
  • FIGS. 2A and 2B show communication channels between positions 1 and 7.
  • FIG. 3 shows the apparatus of FIG. 1 but with wayside train control apparatus added, a train in one of the blocks, and typical messages between each of the transmitters and receivers.
  • FIG. 4 is a block diagram appropriately labeled showing a typical transmitter used on the present invention.
  • FIG. 5 is a block diagram of a typical receiver of the present invention.
  • the concept of the present invention contemplates the use of two sets of center fed track circuits. A first set for providing train detection information and a second set for providing communications from one section of track to the next without the necessity of using line wires.
  • FIG. 1 shows seven apparatus positions which are at spaced distances along the right of way of a continuous rail track system. Transmitters at various locations are denoted by the letter T with appropriate subscripts which shall be described later on and receivers are described by a letter R also with the particular subscript. A numeral before either of the letters T and R will be used to indicate which of the transmitters or receivers is being called for according to its position along the right of way.
  • a first track circuit begins at position 1 at shunt S and continues to position 3 at shunt S. These shunts are used to terminate the continuous rail track circuits and assist in providing definition to the ends of such track circuits.
  • the circuit from 1 to 3 is fed by a transmitter 2T, which is voltage coupled through coil 2C to the rails RR.
  • a signal generated by transmitter T is induced in the rails RR and transmitted in both directions to positions 1 and 3.
  • Receivers 1R and 3R are current coupled to the rails RR and are adapted to receive these signals induced by transmitter 2l Similarly, 4T transmits signals from position 4 to positions 3 and 5 as these signals are received by 3R and 5R In the event of the presence of a vehicle in, for example, the section of rails between positions 3 and 4, the signal from 4T is shunted by the vehicle wheels and 3R does not receive the transmitter 4T signal. Immediately receiver 3R is conditioned to generate signals in accordance with this situation.
  • a second set of track circuits is coordinated with the first set and from FIG. 1 it can be seen that the transmitters 1T 3T ST,,, and 7T are spaced at substantially the same intervals as the previously described transmitter and receivers except that the positions of the transmitters and receivers are shifted over so that they alternate.
  • Transmitter 3T generates control signals and is coupled to the rails for transmitting signals to receiver 2R and 4R and similarly transmitter ST transmits signals through the rails R to 412,, and 6R while transmitter IT, and 7T are respectively coupled through the rails R to their receivers ZR and GR
  • the numbered subscripts on the transmitters and receivers represent those devices used for transmitting the occupancy information while the lettered subscripts of the transmitters and receivers indicate that apparatus which is used for the communications channel of the apparatus of the present invention.
  • the subscripts l and 2 indicate different frequencies of transmission as well as A and B. It will be noted that for the occupancy channel only two frequencies are necessary because the distances between positions are long enough so that there will not be any cross-coupling between different track circuits. It should be noted that the shunts ar positions 1, 3, and 7 terminate the track circuits sufficiently so that this problem does not exist.
  • FIG. 2A shows a typical communications channel from position 1 to position 7, while FIG. 2B shows a channel from 7 to 1.
  • the communication channel exists from each transmitter to each of its associated receivers and from the receivers in one track circuit to the transmitter in the adjacent overlapping track circuit and so forth. This permits continuous transmission of information and control signals from one block to the next.
  • FIG. 3 shows the apparatus as previously described but in addition, includes transmitters IT through 7T which are used for wayside-to-train cab signalling or automatic train operation. These cab signal apparatus may be coupled to the rails RR to a central location over the line wires. Only one train control transmitter T is turned on at any one time, the switching being controlled by the train movement as it is registered at the receiver location directly ahead of the train.
  • H6. 3 provides an illustration of a typical layout with a train placed between positions 4 and 5. The arrows and bracketed legends associated therewith are used to describe the messages transmitted back and forth to the various locations along the right of way.
  • each transmitter in addition to the message is capable of transmitting an address code identifying itself to its adjacent receivers, otherwise said receivers are not capable of using the information so provided.
  • the legends therefore, include the associated transmitter address. The letters following the numbers are used as symbols of the signals being transmitted.
  • a train between positions 4 and 5 on the right of way may, for example, set up the conditions and messages as shown in the FIG. 3.
  • Transmitter 4T generates signals in the rails for transmission to receivers 3R and 5R and when a vehicle V is present between the locations 4 and 5, receiver SR: is apprised of the vehicle presence.
  • the receiver 3R is also notified of this condition because the current induced in the track circuit by transmitter 4T is for the most part shunted across the rails by the presence of the vehicle wheels and receiver 3R reacts thereto by providing some indication of this condition.
  • Each transmission includes identity and a message, the identity having been previously described are the numbers. The remainder of the transmission; that is, the message is carried by another code word.
  • the code word on the cab signal carrier conveys a speed command, for example, 0-60. 0 is the identity of the cab signal channel while 60 is the maximum allowable speed.
  • highway crossings can be overlaid using additional frequencies in the conventional manner.
  • the status of the block is available at any point by simply monitoring one of the signal track circuits, the danger of reading the wrong overlay signal can be eliminated by accepting a signal only when the block is occupied, that is. when the train is shunting the signal from the other transmitters. If the crossing protection is of a type feeding the track at the crossing only, the track signal may not be applied until the approach block is occupied. Switches and other apparatus at the wayside may be controlled similarly by providing different frequencies for different functions.
  • the apparatus of the present invention is shown in FIG. 4 and is typical of that contemplated in the present invention.
  • the transmitter 20 includes an encoder 21 which is capable of providing an address and an appropriate code for particular functions.
  • the encoder drives the high-low frequency shift oscillator 22 which is used to modulate the carrier frequency. This signal is coupled to amplifier 23 for inductive coupling to the rails R over loop 24.
  • Timing apparatus 25 drives the encoder at a proper rate.
  • Receiver coupler 26 is capable of coupling signals from adjacent receivers to the encoder so that appropriate codes may be generated for transmission to the rails and subsequently to other transmitters and receivers.
  • a receiver 30 shown in FIG. 5 includes a current coupled frequency discriminator 31 which detects the carrier frequencies transmitted over the rails RR. If the signal is in proper frequency, it is coupled to amplifier 32 for a gain increase and thence to decoder 33 for a demodulation of the messages therein. Timing apparatus 35 drives the decoder at a proper rate and signal output generator 34 provides signals to the wayside signals and also to its adjacent transmitter as shown in FIG. 1. These transmitters and receivers are only typical of the type which may be used in the present invention.
  • the current coupling as shown in FIG. I for the receivers is used because it provides better zone definition. However, for the purpose, voltage coupling through the loop 24 is also an adequate method of providing the necessary signals to the rails.
  • FIG. 1 it can be seen that the lettered subscript transmitters are coupled to the rails directly by a buffer B. However, they are connected at points capable of transmitting the signals without interference from the shunt.
  • the receiver 5R When a train occupies the zone between 5 and 6 the receiver 5R responsive to this condition provides a signal to transmitter ST which in turn supplies this information to the receiver 4R and thence to 4T coupled as shown. Transmitter 4T relays this information down the rails RR to 3R and 3T Under these conditions, train occupancy information and train controlled information may be transmitted back and forth ahead of and behind the train occupying any one of the block sections.
  • the characteristic of the signals transmitted by each set of track transmitters is chosen for optimum efficiency of the function involved and compatibility one to the other.
  • the signal characteristics for one set of track circuits are chosen for high sensitivity to train shunts for accurate end zone detection while the signal characteristics of the other track circuits are chosen in order to maximize communication distance.
  • Each of the signal characteristics however, are chosen with reference to the characteristics of the other so that the two track circuit systems are compatible.
  • a code communication system for continuous rail track layouts including a plurality of center fed track circuits wherein the improvement comprises:
  • I. train occupancy communication means including:
  • c. means coupled to the occupancy receivers for generating an occupancy signal when communication is cut off from one transmitter and its associated occupancy receiver by a vehicle shunt, and
  • control communication means including:
  • control receivers each selectively responsive to the transmitter frequencies, coupled to the rails at the center of each of the second track circuits for receiving control signals from its associated transmitter, and
  • c. means including the first and second sets of track circuits superimposed one on the other for the same stretch of railway track for activating an occupancy transmitter at a center feed point in each of the first track circuits in response to a control receiver at that point and for activating a control transmitter at the end of each of the first track circuits in response to an occupancy receiver at that point,
  • a distinctive control signal can be communicated through the track layout in either direction by cooperation of the first and second track circuits and the control signal can be modified in character by the presence of a train to provide a double direction railway signaling system without requiring the use of wayside line wires for signal control purposes.
  • a code communication system wherein a train speed control communication means is connected to the track rails at the locations of the occupancy and control transmitters for substantially continuously communicating speed control signals to an approaching train in the associated track section.
  • a code communication system wherein the train speed control communication means is selectively rendered active in accordance with occupancy detection by the first track circuits.
  • a code communication system according to claim 1 wherein at least some of the transmitters and receivers are inductively coupled to the track layout.
  • transmitters and receivers at the center feed points are inductively coupled to the track layout and the transmitters and receivers at the ends of the track circuits are directly connected to the track layout.
  • a code communication system wherein track shunts are provided at spaced locations in the track layout which correspond to ends of the first track circuits.

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  • Engineering & Computer Science (AREA)
  • Mechanical Engineering (AREA)
  • Train Traffic Observation, Control, And Security (AREA)
US34235A 1970-05-04 1970-05-04 Track communication system for continuous rail Expired - Lifetime US3666217A (en)

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US3423570A 1970-05-04 1970-05-04

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US (1) US3666217A (enExample)
BR (1) BR7102669D0 (enExample)
CA (1) CA933642A (enExample)
DE (1) DE2121973A1 (enExample)
FR (1) FR2091199A5 (enExample)
GB (1) GB1352416A (enExample)
NL (1) NL7106056A (enExample)

Cited By (9)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3794833A (en) * 1972-05-25 1974-02-26 Westinghouse Air Brake Co Train speed control system
US3868075A (en) * 1972-07-28 1975-02-25 Westinghouse Air Brake Co Jointless coded track circuits for railroad signal systems
US3897921A (en) * 1973-09-07 1975-08-05 Gen Signal Corp Interlocking track circuits
EP0165048A3 (en) * 1984-06-13 1988-11-09 M.L. Engineering (Plymouth) Limited Railway track circuit equipment
US5330135A (en) * 1991-10-23 1994-07-19 Westinghouse Brake And Signal Holdings Ltd. Railway track circuits
US5459663A (en) * 1993-12-10 1995-10-17 Union Switch & Signal Inc. Cab signal apparatus and method
US6320346B1 (en) * 2000-08-11 2001-11-20 Atlas Model Railroad Company, Incorporated DCC decoder for model railroad
US20050001741A1 (en) * 2003-07-03 2005-01-06 Hiroshi Taoka Automatic train stop system
NL1027459C2 (nl) * 2004-11-09 2006-05-10 Nedap Nv Spoorwegbeveiliging met toonfrequente spoorstroomlopen.

Citations (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
GB840011A (en) * 1957-08-09 1960-07-06 Signaux Entr Electriques A railway automatic block signalling system employing track circuits

Patent Citations (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
GB840011A (en) * 1957-08-09 1960-07-06 Signaux Entr Electriques A railway automatic block signalling system employing track circuits

Cited By (10)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3794833A (en) * 1972-05-25 1974-02-26 Westinghouse Air Brake Co Train speed control system
US3868075A (en) * 1972-07-28 1975-02-25 Westinghouse Air Brake Co Jointless coded track circuits for railroad signal systems
US3897921A (en) * 1973-09-07 1975-08-05 Gen Signal Corp Interlocking track circuits
EP0165048A3 (en) * 1984-06-13 1988-11-09 M.L. Engineering (Plymouth) Limited Railway track circuit equipment
US5330135A (en) * 1991-10-23 1994-07-19 Westinghouse Brake And Signal Holdings Ltd. Railway track circuits
US5459663A (en) * 1993-12-10 1995-10-17 Union Switch & Signal Inc. Cab signal apparatus and method
US6320346B1 (en) * 2000-08-11 2001-11-20 Atlas Model Railroad Company, Incorporated DCC decoder for model railroad
US20050001741A1 (en) * 2003-07-03 2005-01-06 Hiroshi Taoka Automatic train stop system
US7006012B2 (en) * 2003-07-03 2006-02-28 Hitachi, Ltd. Automatic train stop system
NL1027459C2 (nl) * 2004-11-09 2006-05-10 Nedap Nv Spoorwegbeveiliging met toonfrequente spoorstroomlopen.

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Publication number Publication date
CA933642A (en) 1973-09-11
FR2091199A5 (enExample) 1972-01-14
NL7106056A (enExample) 1971-11-08
BR7102669D0 (pt) 1973-06-14
GB1352416A (en) 1974-05-08
DE2121973A1 (de) 1971-12-02

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