Patent GB-492301-A (GB)
Title: Improvements in electric interlocking systems for railway signalling apparatus
IPC: B61L19/06
Filed: 1937-03-18
Abstract: 492,301. Electric interlocking systems for railway signalling. WESTINGHOUSE BRAKE & SIGNAL CO., Ltd. March 18, 1937, No. 8007. Convention date, July 8, 1936. [Class 105] Railway points and signals are actuated in an electrically interlocked manner either individually, by momentary contact devices and associated stick relays, or in a route group, by a route-setting contact device and associated route relay, as desired by the operator. The routesetting and the individual operations may be effected by code from a remote point. The arrangement shown in Figs. 1B, 1C is a direct wire one and route setting is only employed for the main through tracks and in the pertinent direction. The individual operation of the points 1 to the normal position is effected by depressing a push 1N which picks up a stick relay 1NWS, provided that a front contact of a points-locking relay 2MP is closed. A polarized pointscontrol relay 1WR is thus energized in the positive direction over a front contact 31 of the relay 1NWS, a back contact 32 of relay 1RWS, and a front contact 33 of relay 2MP. The points are set to the normal position by a points machine ISM under the control of the relav 1WR. An individual clearing of a signal RC2 for a right-hand bound train in the siding to travel along the main right-bound track (cross-over 3 at normal) is effected by depressing a push 2R which picks up a relay R2HS, provided that an approach locking relay L2MR is energized (no signal cleared for an opposing train). This energizes a signal relay RC2H over a circuit comprising front contact 40 of opposing approach-locking relay L2MR, back contact 41 of opposing-signal control relay L2HS, front contact 42 of repeater relay 3NKP (cross-over 3 normal), front neutral contact 43 of the polarized indication relay 1KR for the points 1, back contact 44 of route relay R2RS, front contact 56 of relay R2HS, front contact 64 of relay 1RKP (denoting points 1 at reverse), winding of relay RC2H and front contacts 50, 63. This clears the signal RC2 and also opens a contact 39 to de-energize the approach-locking relay R2MR so denoting that a signal is cleared for a right-bound train along the main right-bound track (the lower track). The signal is returned to danger by the operator depressing a push 2N to open the stick circuit of the relay R2HS. For the through main-track right-bound route a single push R2P is depressed to set the various points and to clear the signal. The depression of the push R2P picks up the route relay R2RS provided that the points-locking relays 2MP, 4MP and the opposing-signal relay L2HS are closing their front contacts 81, 82, 75. Front contacts 76, 77 of the route relay R2RS then pick up the relays 1NWS, 3NWS, which in turn energize the polarized pointscontrol relays 1WR, 3WR in the normal direction to set the points 1 and cross-over 3 to normal. Front contacts 44, 51 of the relay R2RS energize the signal relay RA2H over a circuit comprising front contact 40 of opposing approach-locking relay L2MR, back contact 41 of opposing-signal relay L2HS, front contact 42 of repeater relay 3NKP for the cross-over at normal, front neutral contact 43 of the polarized indication relay 1KR for the points 1, front contact 44 of the route relay R2RS, back contact 45 of a call-on-signal relay 2US, front contact 46 of relay 3NKP, front contact 47 of repeater relay 1NKP (points 1 at normal), front contacts 48, 49 of track relays 1TR, 2TR of the ahead sections, winding of the signal relay RA2H, back contact 50 and front contact 51. The energization of the relay RA2H clears the high-speed signal RA2 and by opening back contact 37 de-energizes the approachlocking relay R2MR so denoting a signal cleared for a right-bound train along the right-bound main track. A call-on signal RB2 to allow a second train to follow a main-track rightbound train still in the section is given by the operator depressing the route push R2P to pick up the route relay R2RS and then depressing a call-on push 2U. A relay 2US is thus picked and stuck over a front contact 88 of the route relay R2RS. This route relay is at this stage energized by a stick circuit over a back contact 87 of a slow repeater relay 1TP for the track relay 1TR. The route and call-on relays R2RS, 2US being energized, a circuit is closed to the signal relay RB2H over front contact 40 of the opposing approach-locking relay L2MR, back contact 41 of the opposing-signal relay L2HS, front contact 42, front contact 43, front contact 44 of the route relay R2RS, front contact 45 of the call-on relay 2US, frontcontacts 52, 53 of the relays 3NKP, 1NKP, winding of the signal relay RB2H, back contact 64 of relay RA2H, back contact 50 of relay 1RKP and front contact 51 of the route relay R2RS. The interlocking to prevent conflicting and opposing signals being cleared is effected by the approach-locking relays L2MR ... and the points-locking relays 2MP, 4MP. When a left or right-bound signal for the main rightbound track (the lower track) is cleared, an approach-locking relay L2MR or R2MR is dropped and the opening of contact 19 or 18 drops the points-locking relays 2MP, 4MP. Back contacts of the relays 2MP, 4MP maintain the polarized points-control relays 1WR, 3WR in their existing position. The energization of a signal relay such as RA2H requires the opposing approach-locking relay L2MR to be in its energized condition, that is, the opposing signal must not have been cleared. Non-conflicting routes may be set up together. For instance, if the through main-track route push L4P is depressed, the route relay L4RS is energized and a front contact 60 causes the signal relay LA4H to be energized as soon as the cross-over 3 is at normal. The approach locking relay L4MR is then dropped and by the opening of contact 25 thereof drops the pointslocking relay 4MP. If now the other through main-track route push R2P is depressed, the route relay R2RS will be picked up, notwithstanding that contact 82 of the relay 4MP is now open, since a parallel contact 80 of the relay 3NKP (cross-over at normal) is closed. When a signal has been individually cleared for a left-bound train over the cross-over at reverse, the points-locking relay 2MP, in addition to the points-locking relay 4MP, is de-energized to prevent change of the points 1 ; this is effected by the dropped approachlocking relay L4MR opening its front contact 30 which drops a relay 1WS which in turn opens its contact 22 to drop the relay 2MP. The circuits of the approach-locking relays L2MR ... include time-element devices so that after a signal has been manually returned to danger an interval must elapse before a signal for the opposite direction can be cleared.