EP0005968A2

EP0005968A2 - Railway control communication system

Info

Publication number: EP0005968A2
Application number: EP79300940A
Authority: EP
Inventors: David John Norton
Original assignee: Westinghouse Brake and Signal Co Ltd
Current assignee: Siemens Mobility Ltd
Priority date: 1978-05-30
Filing date: 1979-05-25
Publication date: 1979-12-12
Also published as: ZA792481B; ES481081A1; AU4745679A; EP0005968A3; IT7968160A0; GB1604154A

Abstract

An electronic or computer-based railway control system wherein control signals are transmitted between a control or interlocking room and wayside or track equipment by means of time division multi-plexed signais. Several such T.D.M. communication systems are employed in parallel to provide redundancy, and each address location has a majority voting circuit, to determine a correct signal in the event of disagreement between signal, and an out-of-coincidence circuit to indicate which system is carrying the erroneous signal.

Description

The invention relates to railway control systems.
In conventional railway control systems the exchange of vital information between a relay or interlocking room and outside locations, e.g. wayside equipment, is by means of dedicated wires. This means that the wires to distant locations may pass several other wayside equipments and run alongside their particular dedicated wires for considerable distances. Clearly, enormous savings of costs can be made by eliminating the multiplicity of wires laid along the same paths.
According to the present invention, railway control apparatus includes time division multi-plexing means for communicating between equipment locations in a railway system, at least one of the locations being provided with time division multi-plex transmitting means and at least the remaining locations with time division multi-^plex receiving means.
Preferably the time division multi-plexing means comprises a plurality of independent multi-plex receiving/transmitting system and the receiving means at each location is provided with signal comparison means responsive to the independent multi-plexed signals to pass the signals only when a majority of the or all of the signals agree.
In order that the invention may be more fully understood and readily carried into effect, a preferred embodiment will now be described with reference to the accompanying drawings, in which:-

Fig. 1 is a schematic diagram of a triple redundancy T.D.M. link,
Fig. 2 is a schematic diagram of a similar bi-directional link, and
Fig. 3 is a schematic diagram of a T.D.M. railway signalling system.

Referring now to Fig. 1 the time division multi-plex link, hereinafter referred to as a T.D.M. link comprises three independent interlock sub-systems 1, 2 and 3 which are required to communicate central signals to remote trackside or wayside equipment (not shown). The interlock sub-systems 1, 2 and 3 are connected to T.D.M. transmitters 4, 5 and 6 respectively which transmits the signals via pairs of cables 7, 8 and 9 to T.D.M. receivers 10, 11 and 12 located at a wayside equipment. It will be understood that the cables 7, 8 and 9 will continue on to connect to further T.D.M. receivers in other wayside equipments but that these are omitted here for clarity.
The outputs of the three receivers 10, 11 and 12 are connected to both a majority voting circuit 13 and an out-of-coincidence circuit 14. The voting circuit 13 compares the three received signals and if all of or a majority of the signals are equal that signal is taken as correct and is gated to the output 15 of the rating circuit. The out-of-coincidence circuit 14 is responsive to any of the signals being in disagreement to provide an alarm output 16 which indicates that a failure has occurred. This type of triple redundant interlock system is more fully described in our granted U.K. patent specification No. 1,489,921.
Practical examples of a majority rating circuit and an out-of-coincidence circuit are given in our copending U.K. application No. 26665/78.
The three T.D.M. links need not be, but preferably are, synchronised in their operation. If the links are asynchronous it will be necessary to provide temporary signal storage facilities between the receivers and the voting and out of coincidence circuits.
Referring now to Fig. 2, where like parts have like references, the interlocking system 1 receives information from wayside equipments relating to the operative states of control devices, such as track occupancy circuits, signals and points. Signals representing the states of these devices are supplied to a wayside equipment T.D.M. transmitter 17 which multi-plexes the information onto cable 18 connected to T.D.M. receiver 19 back at the interlock room. The information is demulti-plexed and supplied to a voting circuit 20 and out of coincidence circuit 21. The signals 22 then determined as correct are supplied to the interlocking system 1 for the normal interlock control functions to be performed.
In Fig. 2 the complete triple redundancy circuits are not shown for the sake of clarity. It will also be understood that the cables 7 and 18 may be the same cable. Thus for a triple redundant T.D.M. system the cable in each sub-system may be used for transmission in both directions.
In Fig. 2 the signals transmitted by the T.D.M. links are correlated by majority voting circuits after transmission in both directions, that is to and from the interlock system. Alternatively each T.D.M. link to the interlock system may be connected directly to one of the interlock sub-systems, in this case only the majority voting circuit 13 in Fig. 2 is retained for correlating signals received from the interlock sub-systems. Thus effectively the three systems operate independently except in so far as they receive inputs from common sources and provide outputs to control the same devices.
Referring now to Fig. 3 this shows a railway signalling system again with triple redundancy. A control panel 30 can be used to feed information, for example route information, into a supervisory computer 31. The computer displays information relating to track occupancy, train movements etc. by means of a visual display unit (V.D.U.) 32 and also supplies information, such as anticipated route forming control signals to an interlocking computer system 33. The computer 31 also receives information from the interlocking computer 33 relating to track occupancy states and the settings of signals and points.
Computer 31 can also transmit signals to and receive information from a satellite interlocking system 34. The interlocking systems 33 and 34 are both linked to outside locations by triple redundancy T.D.M. links as described with reference to Figs. 1 and 2.
As shown in Fig. 3 various outputs in the signalling system may be recorded in a "black box" type accident recorder so that should an incident occur the recorded signals can be checked to see if the incident was due to control failure.

Claims

1. Railway control apparatus characterised in that it includes time division multi-plexing transmitting/ receiving means (4, 5, 6; 10, 11, 12) for communicating between equipment locations in a railway system, at least one of the locations being provided with time division multi-plex transmitting means (4, 5, 6) and at least the remaining locations being provided with time division multi-plex receiving means (10, 11, 12).

2. Railway control apparatus according to claim 1 wherein the multi-plex transmitting means (4, 5, 6) is associated with the railway system interlock and/or control means (1, 2, 3) and the multi-plex receiving means (10, 11, 12) is associated with railway control devices at distributed locations in the railway system.

3. Railway control apparatus according to claim 1 or 2 wherein the multi-plex transmitting/receiving means comprises a plurality of independent multi-plex transmitting/receiving systems (4/10; 17/19).

4. Railway control apparatus according to Claim 3 comprising three independent multi-plex transmitting/ receiving systems.

5. Railway control apparatus according to Claims 3 or 4 wherein each multi-plex receiving means (10, 11, 12) is connected to signal comparison means (13) responsive to the independent multi-plexed signals to pass the signals only when a majority of the or all of the signals agree.

6. Railway control apparatus according to Claim 3 or 4 wherein each multi-plex transmitting/receiving system (4/10, 5/11, 6/12; 17/19 etc.) is associated with a respective interlock and/or control system (1, 2, 3) and signal comparison means (13), responsive to the independent multi-plexed signals to pass the signals only when a majority of the or all of the signals agree, is located only at the multi-plex receiving means associated with the railway control devices at the distributed locations.

7. Railway control apparatus according to any preceding claim further including supervisory control means (30) for controlling the establishment of routes through or within the railway system.

8. Railway control apparatus according to any preceding claim further including signal recording means arranged to record output signals from the interlock and/or control means, and/or signals from the multi-plex receiving means.

9. Railway control apparatus according to Claim 8 when dependent on Claim 5 or 6 wherein the recording means is arranged to record output signals from the signal comparison means.

10. Railway control apparatus substantially as described herein with reference to the accompanying drawings.