Patent GB-727736-A (GB)
Title: Improvements relating to railway traffic control systems
IPC: B61L19/06
Filed: 1952-03-07
Abstract: 727,736. Railway route-setting apparatus. WESTINGHOUSE BRAKE & SIGNAL CO., Ltd., VENNING, C. F. D., and HAWKES, J. S. Dec. 12, 1952 [March 7, 1952], No. 5986/52. Class 105. Route-setting apparatus operated by pushbuttons or the like on a track diagram panel at the required entrance and exit points on such panel is such that operation of a push-button at the entrance point energizes a " set-up " relay to initiate the setting up of a route and to render the operation of any other push-button effective to energize its associated " destination " relay instead of its associated set-up relay whereby operation of the push-button at the exit point energizes the associated destination relay which together with the set-up relay operates a " route " relay for effecting the setting up of the route. Each of the set-up relays on picking up completes the energizing circuit of a common " conditioning " relay which opens a contact in the energizing circuits of each of the set-up relays and closes a contact in the energizing circuit of each of the destination relays. Operation of a set-up relay effects a flashing illumination indication blue for one direction or yellow for the reverse direction which is changed to a steady illumination by operation of the route relay which also gives to the indication associated with the exit pushbutton a steady illumination to indicate that the exit push-button may be released. In the circuits shown the legend above a contact indicates the relay or other piece of apparatus operating that contact and the numeral underneath the contact indicates the number of that particular contact on that piece of apparatus. The positive and negative terminals of the source of electrical supply for operating the relays are designated respectively by B and N. The route relays, e.g. ABLR, Fig. 5, are assumed to be of the stay-put polar relay type which, when energized, remain in the position to which they were last operated. Each is provided with a reverse coil (R) and a normal coil (N) and one route relay is provided for each route to be set up, the operation of the relay to its reverse position correctly setting the points for that route and causing the signal governing the entrance to the route to clear. Two separate relays may be used instead of each polar relay. In the system shown in Fig. 1, traffic may take place in both directions. To set up a route from B to C, push-button BPB is first operated to close contacts BPB2 and BPB3, and to open contacts BPB1 and BPB4, all shown in pushbutton repeater relay circuit lay-out of Fig. 2. Push-button repeater relay BPBR pulls up over a circuit including contacts APB1, BPB2, CPB4, DPB4, BPB3 and picks up the set-up relay BSR, Fig. 3, at its contact BPBR1 over the circuit including the back contact CR1 of a conditioning relay and back contact BDR1 of the destination relay associated with pushbutton BPB1. Relay BSR is held at its front contact BSR1 over " cancel " push-button contact 1 and back contact DRP2 which is in parallel with front contacts ADR2 and CDR2 of destination relays ADR and CDR associated respectively with push-buttons APB and CPB at the ends of routes having the entrance B. At front contact BSR8, Fig. 7, a circuit is completed for flashing the blue indication lamp B(B)KE, for traffic from right to left, Fig. 1, to indicate that the correct set-up relay has picked up. The normal closed contacts BALR4 and BCLR4 in this circuit are to remove the flashing source BX (Flash) after the desired route has been established from point B. Release of button BPB opens contacts BPB2 and BPB3, causing relay BPBR to fall away opening its contact BPBR in the pick-up circuit of set-up relay BSR which is now held over its holding circuit, Fig. 3. At front contact BSR2, Fig. 4, in parallel with front contacts of other set-up relays and a front contact DRP5 of the destination repeater relay DRP, conditioning relay CR is pulled up. At front contacts BSR5, BSR6, Fig. 5, circuits for the route relays of all routes, e.g. B-A and B-C having point B as their entrance end, are prepared to reverse the relays when the appropriate destination relay is subsequently energized. To cancel the set up at this stage, the holding circuit of relay BSR, Fig. 3, is opened at the cancel push-button contact 1, release of relay BSR being followed by release of relay CR, Fig. 4. When relay CR pulled up, at back contact CR1, Fig. 3, it opened the energizing circuits of all the set-up relays ASR &c. and at front contact CR2, Fig. 4, applied battery feed to the energizing circuits of the destination relays ADR-DDR to render all buttons other than BPB as exit buttons and the next one to be operated energizes its destination relay. Thus operation of button CPB pulls up its repeater relay CPBR, Fig. 2, which at its front contact CPBR2, Fig. 4, completes the energizing circuit of destination relay CDR, which, at its front contact CDR4, Fig. 4, pulls up slow release repeater relay DRP which at back contact DRP2, Fig. 3, opens the holding circuit of set-up relay BSR, but this circuit is maintained by front contact CDR2. At contact CDR5, Fig. 5, the reverse coil BCLR(R) of the route relay BCLR for route B-C is energized interlocking permitting, to set the cross-over and clear the signal at point B. At back contact BCLR4, Fig. 7, the flashing supply to blue indication lamp B(B)KE is interrupted and at front contact BCLR5 is replaced by the steady supply BX (Steady) which at front contact BCLR6 is also connected to the blue lamp C(B)KE, the two steady blue lamp indications indicating that the route B-C has been set. Button CPB on release drops away relay CPBR which at contact CPBR2, Fig. 4, drops away destination relay CDR to open at CDR2, Fig. 3, the holding circuit of set-up relay BSR and at contact CDR4, Fig. 4, to de-energize repeater relay DRP which drops away after sufficient time to ensure that relay BSR has had time to open its holding contact BSR1, Fig. 3, before contact DRP2 in series therewith is closed. Opening of contact BSR2 releases relay CR. The route relay BCLR, Fig. 5, may be returned to normal, thus releasing the route set up, either manually or automatically by the passage of a vehicle, by means of a normalising relay operated by the set-up relay and providing a holding circuit for itself including a train-operated contact which opens when the train enters a suitable track section along the route, and a contact on the entrance button which is closed when the button is in its normal position or depressed position for setting a route, but which is broken when the button is pulled instead of pressed. The energizing circuits of the normal coils of all route relays such as BCLR(N) of routes originating at a common point are connected in parallel and contain contacts of rear locking track relays, if required, and of an approach locking relay and a back contact of the normalising relay. To guard against accidental cancellation of a route on account, for example, of a broken wire, a front contact of the normalising relay may be included in the pick-up circuit of the route relay normal or (N) coil in place of the back contact of the normalising relay. Instead of the interlocking contacts being provided on the push-buttons as shown in Fig. 2, they could be provided on the pushbutton repeater relays APBR &c. When a button is pressed which cannot be the exit button of a previously pressed entrance button, contact CR1, Fig. 3, is open and prevents a second set-up relay from picking up, the holding circuit for the previously operated set-up relay being opened by the picking up of the destination repeater relay DRP, e.g. at contact DRP1, Fig. 3, and on release of the second operated button the apparatus automatically resumes its normal position. When it is required to set up a route comprising a number of route sections as described above, the route may be set by operation of the sectional buttons in the correct sequence. Alternatively, the through route may be set by operating in correct sequence the entrance and exit buttons. To this end the energizing circuits of each route relay, in addition to the front contacts of the associated set-up relay and destination relays, has a by-pass circuit around the set-up relay contact, this by-pass circuit being completed when the section of the route in rear has been set up and the signal at the entrance thereof has cleared. When route stick relays are used for storing each route section as required, the operating circuit for the route relay of each route section includes a contact closed when its associated route stick relay is energized in parallel with a circuit which is completed when the immediate rear route section is set up. Specifications 499,340, 518,422 and 649,063 are referred to. Reference has been directed by the Comptroller to Specification 524,872.