Patent GB-191412957-A (GB)
Title: Improvements in Railway Signalling.
Inventor: COOKE CHARLES JOSEPH
IPC: B61L13/04
Filed: 1914-05-26
Granted: 1915-03-25
Abstract: 12,957. Cooke, C. J., Johnson, A. H., and Downes, F. May 26. Combined electrical and mechanical systems, non-automatic; signals and points, interlocking. -Relates to systems of the kind in which a long block section of track for one-direction traffic is protected at each end by means operated by the train entering and leaving the section. Each block comprises an entrance section x, which may be a track-circuit section or provided with a treadle, a long plain midsection y, and an exit track-circuit section z, the sections x, z being connected to relays 10, 11 respectively. When a train is offered by A to B and the line is clear, the accepting-switch 1 is operated to close the circuit of a battery 2 and energize a polarized relay 16 at A, the armature of which then closes a switch 17 in the circuit of the starting-signal lever lock 19. This circuit may then be closed by the trigger switch 25, a reverser 26 controlled by an electro-magnet being fitted in the circuit as shown. The relay 11 normally maintains closed a switch 32 in a circuit comprising the line 5, electric indicating - instruments, and a battery 2. Through this circuit, the relay 10, when de-energized by the short-circuiting of a train in the section x, closes the circuit of a battery 28 of opposite polarity to, and stronger than, the battery 2. The indicators then show ' train in section,' and the armature 24 of a relay 22 closes the circuit of a holding-coil 30 and a battery 31 of opposite polarity to the battery 2, to maintain the indication. When the train enters the section. z, the relay 11 is de-energized, causing the disconnexion of the relay 22 from the line, which is still in circuit with the batterv 31 to maintain the indication. As a safeguard against de-energization of the holding-coil 30, the switch 24 is arranged to close at 35 an auxiliary circuit, which is bridged at 36 by the armature 33 of the relay 11. When the train leaves the section z, the relay 11 cuts out the battery 31 from the line circuit, and the indicators show ' line clear ' if the battery 2 is still left in. The safety arrangements for shunting are shown at C and D, in which the exit section z is divided into a ' guard ' subsection zg, and a shunting subsection zs comprising all the points. One rail of zg is insulated from the corresponding rail in zs, but may be connected thereto through the switch 40 when the signal 37 is at ' clear,' the other rails being bridged at 38. Referring to the arrangement shown at C, in order to stop a train in zg before the shunting-points are set, C turns the switch 1 to ' line blocked ' and thus closes the switch 45, The shunting- point lever is then freed through the circuit of battery 42, switches 48, 45, magnet 46, and trigger 47. If, however, the line circuit is closed, in which case the relay 49 is energized and the switch 48 open, an alternative circuit is made through battery 42, switch 51 (the signal 37 being at danger), contact 50 (the relay 11<g> being de-energized), to switch 45. To prevent C from accepting a second train from B while (1) a train is in the section zs or (2) the shunting-points are still set, the switch 1 is provided at one side with a double terminal 4, 4* so arranged that the switch 1 connects 3 to 4* in the line clear ' position, and 3 to 4 and 4* in the train in section ' position. The accepting-circuit is broken (1) at 53 with a train in the subsection zs, and (2) at 52 with the shunting-points set. In the further arrangement shown at D, to permit the acceptance of a second train from C up to the signal 37 of the guard subsection zg, even though the subsection zs is not clear, the lead from the terminal 4* is branched to a switch 54 adapted to close the accepting-circuit through the switch 52, armature 24, relays 49, 58, to the line 5. The switch 54 is held closed against spring-pressure by a plunger 57, which is normally operated when the accepting-indication is given, and is automatically withdrawn when the train enters the section. The relay 58 is not responsive to the ' accepting' current, but is energized with ' train in section ' when the switch 54 is opened, and the switch 55 closed, automatically. The circuit for the trigger 44 of the signal 37 is then broken only at 43, and this is closed to allow the second train to proceed, when the first train clears the section zs. An indicator 61 is provided to show the condition of the shunting subsection. The pole-changing switch 1 may be replaced by a self-holding switch to obviate the necessity for restoring the switch by hand after an accepted train has entered the section.