Patent GB-716220-A (GB)
Title: Automatic route control system for railways
IPC: B61L25/04
Filed: 1952-06-18
Abstract: 716,220. Railway route setting apparatus. WESTINGHOUSE AIR BRAKE CO. June 18, 1952 [July 27, 1951], No. 15310/52. Class 105 Route control apparatus for railways is, by means of a changeover relay, alternatively manually controlled or automatically controlled by a train describer system of the kind which registers indications of the routes of approaching trains in the order of their entrance into an approach zone, for establishing routes for the trains corresponding to the registered indications, said relay being energized for the automatic control and retained energized by track circuit controlled means only so long as route indications for approaching trains continue to be registered, said relay being released for the manual control. The pick-up and stick circuits for the changeover relay include a manually operable contact device, the pick-up circuit also including a further normally open, manually operable contact and also contacts of, e.g. track relays or directional stick relays, which are closed only when no vehicle occupies the routes registered by the describer system or the approach zone to said routes and the stick circuit of the changeover relay also includes a contact device controlled by the describer system so as to be closed only when predetermined descriptions are registered thereby. This stick circuit is opened when a train enters the approach zone unless its route is registered on the describer system. Under manual control switch locking arrangement are effective, when a route has been established and the signal cleared to prevent the establishment of a conflicting route from the time of conditioning the entrance signal for clearing until the route is vacated whereas under automatic control the switch locking arrangements are effective for an additional period which begins when the route is vacated. To this end an approach locking relay controls a switch locking relay, the approach locking relay being energized over either of two circuits, one of which includes a contact device of a time delay relay which is effective. under the automatic control. Fig. 1A shows the circuitry in accordance with the train describer system described in Specification 715,992 in which indications of the route of each of a series of trains which travels over the same' stretch of track is displayed automatically at the wayside station approached and in which the indication of each train is cancelled upon its arrival at the station and then superseded by the indication for the next following train. Fig. 1B shows the circuitry for the route selecting relays of an interlocking route-selecting system of the entrance-exit button type as described in Specification 533,218 the circuits having been modified to include the changeover relay APBS with relays governed thereby which enable the describer system to operate automatically the selecting relays for certain routes. Fig. 1F shows the circuits for approach locking relays and time delay relays controlled by the route check relays and by the signals, by means of which the track switches and opposing signals are electrically interlocked. In the drawings negative battery pole is designated by " N " and the positive pole by " B." " BX " or " NX " represent the terminals of an alternating current supply. The designations of relay contacts will include the designation of the relay to which they belong and will be preceded by f or b indicating that the contact is a front or back contact. Thus fITRb means front contact b of relay ITR. In the plant shown in Fig. 1A the trains V which traverse the stretch of track are equipped with automatic speed control and cab signalling apparatus of the continuous inductive type, the apparatus being controlled by periodically interrupting the track A.C. current at different rates and so as to provide an overlap block system of control. The various routes through the plant will be designated by the numerals which identify the signals at their opposite ends, viz. 2-6 ; 2-8 ; and 4-8 having entering signals .2A, 2B, 4 and the opposing routes 6-2, 8-2 and 8-4 having the entering signals 6, 8B, 8A. Of these routes 2-6 and 2-8 are controllable automatically by the train describer system. The approach zones for signals 2A, 2B comprise track sections 10T, 12T and 14T and its occupancy by a train is indicated by the release of an approach relay 2AR. This relay and relays 1TR, 2TR control indication lamps on the illuminated track diagram. The means for changing over from automatic to manual control and vice versa consists of a change-over switch operable between two positions which is incorporated in the route selecting push button 2PB, Fig. 1B. The length of the approach zone accommodates only two trains at the same time and the storage indicator thus comprises only two storage-units. Two similar train reporting devices TD1, TD2 are controlled by train-carried marker coils and are located at the entrance to the approach zone and at the entrance to the interlocking plant in the rear of signal 2A. In device TD1 the output of each secondary winding is fed to its respective detector relay AD, BD, ND but in device TD2 the outputs of all the secondary coils are fed to a common detector relay CN which cancels the indication set up by device TD1. This cancellation may also be effected by an emergency key CNB. In Fig. 1B the route selecting relays ANE and RE associated with button 2PB respectively select routes 2-6 and 2-8. To set the plant for automatic control button 2PB is rotated clockwise to close contact d and then depressed momentarily to close contacts a, b. With no train in the approach zone or on any of the routes, relay APBS is energized over contacts d, b of button 2PB, line 21; f 2TRa, f 1TRa and f 2ARa to battery B at f 14TRb. Relay APBS sticks over its contact a, line 22 to battery B on f 14TRb. When a train carrying a marker coil enters the approach zone one of the detector relays AD, BD or ND operates momentarily closing at its contact a a circuit for directional stick relay 14SR which locks over contacts f 14SRa and b 14TRc. At f 14SRb relay APBS is held energized when relay 14TR is dropped away. Since two trains cannot occupy the same section, relay 14TR will pick up to release 14SR before a following train can enter section 14T. In the absence of any registered indication on the describer systems, relay L2 is held energized over its stick circuit including f L2a and b N2d, bB2d and b A2d. Assuming the train passing the device TD1 operates detector relay AD relay A2 picks up followed by relay A1 which releases relay A2. At f Ale indicator lamp AE is lighted to indicate route 2-6. At f Alb relay AP, Fig. 1B, is operated and at f APa picks up selector relay ANE for route 2-6 from battery B on f 1TRb, f APa, b ANWb winding ANE, b RWe, to battery N on wire 26 over a back contact of the reverse lever repeat relay RLP (not shown) and a back contact of the reverse switch indication relay RWK (not shown). Relay ANE sticks over its contact f ANEa and energizes the route exit relay 6XS. Fig. 1B for route 2-6, from battery B on f APb, f ANEc windings of relay 6XS, f 6ASc (approach locking relay) to negative battery. The normal lever repeat relay NLP (not shown) is energized over a front contact of relay 6XS (the switches 1 A, 1 B are normal for route 2-6) and a back contact of the reverse lever repeat relay RLP (not shewn). Since points switches 1A and 1B are already in position required for route 2-6, switch operating relay NWS (not shown) and switch correspondence relay NWC (not shown) are energized and hence switch indication relay NWK (not shown) is energized. Operation of relay NWK enengizes a route check relay 2 RR over a contact of relay CXS. In. Fig. 1, F approach locking relay 2AS is released at b2RRc and in turn releases switch locking relay LS (not shown), and operates mechanism 2AG for.changing the signal 2A from stop to proceed or caution to authorise the train to enter the established route. A second train now passing the reporting device TD1 operates detector relay BD Fig. 1. Relays B2 and 14SR will operate and relay B2 will release relay L2. As the first train has not yet passed device TD2, relay A1 is energized and relay L1 released and the route indication for the second train is stored in relay B2. As the first train now passes the devise TD2, located a short distance in the rear of signal 2A, but not yet having entered section IT to shunt relay ITR, relay CN is operated momentarily to open at its contact a the holding circuit of relay A1 which releases cancelling the indication by lamp AE and at fA1b releasing relay AP, Fig. 1B. Relay B1 is energized and locks over its front contact a. Relay B2 is released at bB1d and lamp BE is lighted at fB1e to display the indication for route 2-8. At fB1b repeater relay BP, Fig. 1B, is energized over wire 24. The change in the route indication is without effect upon the established route and signal 2A will continue to display its indication until the first train enters section 1T relay 1TR releasing and at 1TRb, Fig. 1B, in turn releasing relays ANE, 6XS, NLP and 2RR, this latter relay de-energizing the signal changing mechanism to put signal 2A to stop. On the train vacating section 1T and the route 2-6, relay 1TR picks up and completes at f1TRg, Fig. 1F, a circuit for the time element relay 1TER over b2RRc; b2AGa; b2BGa, b2ASa; f1TRg, fNWCf; winding 1TER. Relay 1TER on energization opens a quick-acting contact in the circuits of the signal mechanisms 2AG, 2BG and after a predetermined interval closes contacts f1TERa and b energizing over the contact a and over b2RRe relay 2AS which relay sticks over f2ASa and at b2ASa releases relay 1TER. The switch-locking relay is now energized over an interlocking chain of contacts including f2ASd and locks opening the energizing circuit of switch indication relay NWK (not shown) which connects terminal N again t