GB1604154A - Railway control systems - Google Patents

Description

PATENT SPECIFICATION

( 11) 1 604 154 ( 21) Application No 24016/78 ( 22) Filed 30 May 1978 ( 19) ( 44) Complete Specification Published 2 Dec 1981 ( 51) INT CL 3 H 04 Q 9/00 ( 52) Index at Acceptance G 4 H 13 D 14 A 14 D 1 A NC 3 ( 72) Inventor: DAVID JOHN NORTON ( 54) IMPROVEMENTS RELATING TO RAILWAY CONTROL SYSTEMS ( 71) We, WESTINGHOUSE BRAKE AND SIGNAL COMPANY LIMITED, a Company incorporated under the Laws of Great Britain, of 3, John Street, London, -.5 WC 1 N 2 ES, England, do hereby declare the invention for which we pray that a Patent may be granted to us, and the method by which it is to be performed, to be particularly described in and by the following statement:The invention relates to railway control systems.

In conventional railway control systems the exchange of vital information between a is 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 there is provided a railway control system comprising interlock control means at a central location, wayside equipment at a plurality of distributed locations, a plurality of parallel redundant time-division-multiplex (T.D M) links for two-way communication between the central and distributed locations, majority voting circuit means at each wayside location connected to each of the T D M links to receive therefrom parallel redundant wayside equipment control signals generated by the interlock control means and operative to determine the most likely correct control signal in the event of disagreement between the control signals, and out-of coincidence circuit means associated with and parallel to each voting circuit means to determine that a communication link is carrying an erroneous control signal.

4 S 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 transmit 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 of the voting circuit The out-ofcoincidence 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 number 1,489,921.

Practical examples of a majority voting circuit and an out-of-coincidence circuit are given in U K Patent Specification No 2 022

893.

I"r " 5 "S 1,604,154 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 demultiplexed 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 70 was due to control failure.

Claims (4)

WHAT WE CLAIM IS:-

1 A railway control system comprising interlock control means at a central location, wayside equipment at a plurality of 75 distributed locations, a pluarality of parallel redundant time-division-multiplex (T.D M) links for two-way communication between the central and distributed locations, majority voting circuit means at each 80 wayside location connected to each of the T.D M links to receive therefrom parallel redundant wayside equipment control signals generated by the interlock control means and operative to determine the most 85 likely correct control signal in the event of disagreement between the control signals, and out-of-coincidence circuit means associated with and parallel to each voting circuit means to determine that a communication 90 link is carrying an erroneous control signal.

2 A railway control system according to Claim 1 wherein the interlock control means comprises a plurality of parallel redundant sub-systems and further majority voting 95 circuit means and associated out-ofcoincidence circuit means at the central location are connected to receive equipment status indicating signals from each wayside location via the parallel redundant T D M 100 links.

3 A railway control system according to Claim 1 wherein the interlock control means comprises a plurality of parallel redundant sub-systems each of which is independently 105 connected to a respective one of the T D M.

links for indepenent operation in conjunction therewith.

4 A railway control system according to any preceding claim further comprising sig 110 nal recording means arranged to record outputs in the signalling system.

A railway control system substantially as herein described with reference to the accompanying drawings 115 A.R TURNER.

Printed for Her Majesty's Stationery Office.

by Croydon Printing Company Limited Croydon Surrey, 1981.

Published by The Patent Office, 25 Southampton Buildings, London WC 2 A i AY from which copies may be obtained.