Patent GB-815542-A (GB)
Title: Railway signalling equipment
IPC: B61L19/06
Filed: 1956-07-27
Abstract: 815,542. Railway signalling equipment in route-setting systems. STANDARD TELEPHONES & CABLES Ltd. July 27, 1956 [July 30, 1955], No. 23307/56. Class 105. In a railway network of points through which a route can be established, the signal at the entrance to the route is operated to an aspect appropriate to the route in response to a predetermined code received by a codereceiving apparatus at the routeentrance end from a code-sending apparatus at the route-exit end over a supervisory circuit including electrical contacts corresponding to the positions of the points comprised in the route. In the embodiment described, the code consists of three code elements, viz. direct current, alternating current and absence of current allotted in various arrangements to three transmission circuits each comprising a supervisory circuit so that each code differs from every other code in respect of the conditions in two of the circuits. A distinctive code is assigned to each exit route end but where the same signal aspect is required for several entrance signals a common code may be assigned to the appropriate route ends. The signal control relays, after responding to the code are held in stick circuits and then the code transmission circuits can be used for other purposes such as route proving circuits by including in them contacts of points detector relays, or contacts of track repeater relays. The transmission circuits may also be used for controlling distant signals in dependence upon main signals. To this end after transmission of the code, the transmission circuits are connected at the end of the route to contacts of relays assigned to the main signals and at the beginning of the route to control relays assigned to distant signals. Assume the route from the main track b, Fig. 1, to the track 14 has been lined up so that points 2 and 3 are in the reversed position and points 5 and 7 are in the normal position. Signals 11, 12, 14 are starting signals and control the distant signals 11/12/14 on the home or main signal B. The supervisory circuit diagrams simulating the track diagram, for the transmission of the code elements are shown at X and Y, Fig. 2, and at Z, Fig. 3. Assume the code for the route set are A.C. on circuit X, no current on circuit Y, and D.C. on circuit Z. With the route assumed lined up, the points detector contacts U21 -, U31 - (points 2 and 3 reversed), U51+ and U71+ (points 5 and 7 normal) in circuit X and contacts U22 -, U32 -, U52+ and U72+ in the circuit Y, are all closed. In circuit Z, Fig. 3, contacts 2R and 3R of points position control relays of points 2, 3, the positions of which correspond to the positions of corresponding points tongues, are reversed while contacts 5R, 7R associated with points 5, 7 are as shown. With the track sections clear, contacts G21, G31, G51, G71 in circuit X of the corresponding track relays G2, G3, G5, G7, Fig. 1, and contacts G22, G32, G52, G72 in circuit Y are closed. In circuit X A.C. then flows via contacts 14F1 to G21 to the end of the circuit indicated in broken line which continues in the same way as the lower part of Fig. 2 via contact W4 of a stick-and-latch type signal repeater relay (shown only for signal A, but that for signal B is arranged similarly) and a contact X5 of an auxiliary signal relay X, through a condenser CX to an A.C. code element receiving relay WX. The circuit is dead since its code element is absence of potential. In the circuit Z D.C. flows via contacts 14F2, 7R, 5R, 3R, 2R to a contact such as W6 of the repeater locking relay for signal B, contact Z5 of an auxiliary relay associated with signal B to the direct current code element receiving relay GZ. On operation, the relays WX and GZ close contacts in a circuit for operating in series an auxiliary relay Y (not shown) and a signal control relay N (not shown) for the green/yellow lamps of the signal B and those relays Y, N, establish a stack circuit for themselves. At contact N2, Fig. 6, the lamp Lge2 is switched on in series with the lamp circuit supervisory relay U4 over contacts L4 of a cancellation relay and U71 of a lamp circuit supervisory relay U7 associated with signal B and the lamp Lge1 is switched on in series with the supervisory relay U3 over contact U61 of lamp circuit supervisory relay U6 of lamp Lgn1. At contact Y5, Fig. 2, D.C. voltage is applied to the circuit Y to energize both windings I and II of the stick- and-latch relay 14F over contacts W5, G22, U22-, U32-, G32, G52, U52+, G72, U72+ and 14F4. The armature of winding I when energized, reverses the contacts 14F1, 14F2 while the other contacts of the relay, operated by armature II remain as shown. At contact 14F1, the X circuit, Fig. 2, and at contact 14F2, the Z circuit, Fig. 3, are interrupted to cause relays WX and GZ to drop away. Both windings of the stick-and-latch signal repeater relay W, Fig. 6, can be re-energized via contacts S4, Y1, GX4, WX4 (now closed), GY4, WY4, GZ4, WZ4 and W7. Initially, only the contacts W1-W6 controlled by armature I are reversed. at contact W5 the circuit Y is interrupted to de-energize the windings I and II of relay 14F, the winding I being slow to release so that the armature of winding II releases and armature II latches armature I in the attracted position. The main signal control relay S is then energized with D.C. via contacts 14F3, U71+, G71, U51+, G51, G31, U31 -, U21 - and G21, contact W4 of the repeater locking relay of signal B and resistance Wi1, contacts U31 and U41 of lamp circuit detector relay U3 and U4, Fig. 6, contact W10 to the circuit Y shown by broken lines, contacts G22, U22 -, U32 -, G32, G52, U52+, G72, U72+, reversed contact 14F4. Relay S operates and at contact S1 establishes a stick circuit. At contact S4, Fig. 6, relay W is de-energized again, and owing to slow release of winding I armature II drops off first and latches armature I in the attracted position. On closing of contact S2, Fig. 6, the lamps Lge and Lgn of the main signal B are lighted over contact W9 (now closed), contacts M1, W1 (operated) supervisory relay U2. In a circuit, not shown, the supervisory relay U2 on operation cuts off the "stop " light previously switched on. If the signal 14 shows a " clear " aspect then one of the relays GZ or WZ, Fig. 3, is re-energized over contact 14F5 and one or other of contacts 14U29 or 14U19 of the "clear lamp supervisory relays of distant signals 11/12/14 on the main signal post B. For example, if signal 14 displays either of its proceed aspects, e.g. green/yellow, contact 14U29 is closed and relay WZ is then energized and at contact WZ5 reversed, Fig. 6, the supervisory relay U6 is energized in series with the resistance Wi3 and lamp Lgn1 at the distant signal 11/12/14 and the lamp is lighted. At contact U61 the supervisory relay U3 and the lamp Lgel are de-energized; the distant signal 11/12/14 then displays a signal aspect appropriate to that of the signal 14. When the train passes signal B, the track relay G2 is deenergized and at contacts G21, G22, Fig. 2, interrupts the holding circuit of relays, which relay S drops off and cannot respond again as contact W10 has opened meantime. The dropping away of relay S is followed by the dropping away of the auxiliary relay Y7 (not shown) and the signal control relay N (not shown) for the green/yellow aspect of signal B and at contacts N1, N2, Fig. 6, the lamp circuits of the main green signal lamp and distant yellow signal lamps are interrupted. The supervisory relay contact U21 switches off the green lamp Lgn1. At contact W5, Fig. 2, relay WZ is released. The stick-and-latch relays 14F and W are restored by circuits, not shown, the windings II of the relays being energized. A further example is described in which an additional indicator Z, consisting of four lamps LWS1- LWS4 is used to prescribe a speed restriction for a train entering the blind track 13. When trains enter from track b to track 11 a white identification lamp LSW, Fig. 6, lights up at distant signal 11/12/14 on main signal B to indicate that the brake distance is reduced.