Patent GB-389307-A (GB)
Title: Improvements in electric interlocking systems for railways
IPC: B61L19/06
Filed: 1932-05-11
Abstract: 389,307. Electric interlocking systems for railways. GENERAL RAILWAY SIGNAL CO., Rochester, New York, U.S.A. -(Assignees of Wight, S. N. ; 226, Thurston Road, Rochester, New York, U.S.A.) May 11, 1932, No. 13591. Convention date, May 28, 1931. [Class 105.] An electric interlocking system comprises arrangements by which, after a route has been prepared by operating the various points, a circuit is set up which includes two route relays for controlling the two signals for the two opposite directions of travel with electrically interlocked means to allow energization of the circuit at one end only at a time so that on operating the lever for the signal for one direction that signal only can be cleared. Fig. 2 shows a track lay-out operable to set up a number of different routes with signals 1, 2, 3 for east-bound traffic and signals 4 .. 7 for west-bound traffic. Each signal lever L<1> .. controls its stick relay SS<1> .. and route relay RR<1> ... The points and cross-over are shown in full lines set to give two routes, namely, between signals 2 and 5 and between signals 3 and 7 and it will be seen that route relays RR<2>, RR<5> are connected over points detector contacts 118, 120, 122 and that route relays RR3, RR<7> are connected over points detector contact 129. To clear signal 2 the lever L<2> is operated to pick up relay SS<2> over a back contact of relay RR<2>; relay SS<2> then sticks and front contact 115 thereof now energizes the two route relays RR<2>, RR<5> the latter breaking the pick-up, circuit for relay SS<5> so that any operation of the lever L<5> would have no effect. The signal 2 is cleared over front contacts of the relays SS<2>, RR<2>. Fig. 1 shows in greater detail the control and cabin indication arrangements for a single set of points with track circuit control of the signals and points, the cabin apparatus being shown within the dotted rectangle DO. The points machine SM is supplied with current over a contact of a polarized master relay MR a further contact 58 of which acts in conjunction with points detector contacts 56, 57 to energize a polarized points repeater relay WP. The operation of the points is subject to control by a lock relay L such as an approach locking relay. To put the points to reverse the cabin lever SML is moved to the dotted position to close a circuit from negative battery 35 through upper winding of relay K, stick contact 51, normal contact 40 of a polarized points-repeater cabin relay WPP, contact 42 of relay L, and winding of relay Z to the common line 46. Contact 54 of relay Z now being at reverse a potential difference is applied to relay MA as contact 55 of relay MR is still at normal. Relay MA therefore closes its contact 26 to put relay MR to reverse, the contact 26 opening as soon as this is effected since, contact 55 having moved to reverse, a potential difference is not now applied to relay MA. Relay MR at reverse causes the points to be put at reverse, the detector contacts 56, 57 moving over so that the two points repeater relays WP and WPP are now at reverse, the latter being energized from negative battery 47 over reverse and neutral contacts 61, 62 of relay WP and contact 63 of detector track section relay DT. Contact 60 of relay WP at reverse causes a relay RWP to be energized over reverse contact 52 of relay Z and so to connect up route relay 23RR with route relay 20-21 RR over contact 107 of such relay RWP ; relay NWP is dead since contacts 60, 52 are not at normal. To clear a signal, for eastbound traffic, the cabin switch 30-31 is operated whereby stick relay 20-21 SS is picked up over back contact 73 of its associated route relay 20-21 RR and then stuck over its own front contact 74 ; front contact 75 of the stick relay then energizes the two connected route relays 20-21 RR and 23RR. The signal 21 is cleared since the points have been set at reverse as above described. The signal is cleared by the energization of its control relay 21G over front contacts 79, 78 of stick relay 20-21SS, front contact 88 of route relay 20-21RR, contact 86 of side track section relay TT, contact 104 of the now energized relay RWP and contact 92 of detector track section relay DT. If the points had been at normal the signal 20 would have been cleared by the energization of relay 20G over front contacts 77, 76 of the stick relay 20-21SS, contact 87 of route relay 20-21RR, contact 96 of main track section relay MT, contact 94 of relay NWP which would be energized with the points at normal, and contact 92 of detector track section relay DT. If the cabin points lever SML is moved while the lock relay L is de-energized, as by an approaching train, the points will not be subsequently operated since the dropped relay K can only be picked up when the lever contact and the contact 40 of the cabin points repeater relay WPP correspond ; the points of course cannot be operated when the train is approaching as the front contact 42 of the lock relay L opens the circuit to the points control relay Z while the back contact 42 maintains the relay Z in its condition at that time. The de-energization of relay K by the dropping of the lock relay L causes a lamp LO to be lit denoting that the points are locked against operation. When the detector track section is occupied a lamp TR is lit over back contacts 64, 65 of relays WPP, K. During the moving over of the points a lamp TL is lit over back contact 64 of relay WPP and front contact 65 of relay K.