Patent GB-191304901-A (GB)
Title: Automatic Wireless Train Control Apparatus.
Inventor: CLARK THOMAS EDWARD
IPC: B61L3/22
Filed: 1913-02-26
Granted: 1914-02-26
Abstract: 4901. Clark, T. E. Feb. 26, 1912, [Convention date]. W i r e l e s s systems; track apparatus actuating signals on trains and for stopping trains. -High-frequency highpotential currents supplied to two track conductors laid parallel to the rails and connected to two poles of the generator are received on trains by conductors supported so as to be parallel and near to the track conductors, relays being included in the receiving circuits to actuate signalling and train-controlling apparatus, when the track conductors are de-energized by a train in advance which short-circuits a track relay. Fig. 5 shows parts of three block sections of track with the apparatus on the track and the apparatus on a train 130 in block B when a train 138 is also in block C short-circuiting the relay 10 of that block, and opening the primary circuit of the transformer 20. This circuit includes a reactance regulator 15 and is supplied with current from the mains 6, 7. The secondary winding of the transformer is connected to the sparking terminals 31, between which a disk 29 is rotated by a suitable motor so as to bring studs thereon opposite the terminals 31, just before the moments of maximum potential of the circuit. The moving disk and studs serve to remove metallic vapour from the sparking gap. These terminals are each connected through a condenser with a linking coil to which adjustable connexions are made to a track wire 28, which extends from the insulated joint between the blocks B, C, a short distance into the block B, and to the wire 27, which extends through the remainder of block B and into the block A, nearly to the conductor 27 of that block. High-frequency oscillations are thus set up in the circuit including the track wires so long as the track-relay of the advance section is energized, and a train on section B would receive current through its collectors 53, which comprise a number of parallel wires connected at their ends ; this current passes through the wire 54, front contacts of the relay 57, wire 59, to the thermal relay 60, and to earth through the adjustable inductance 61. The collector and track conductor are believed to form the metallic members of a condenser, the intervening air serving as the dielectric. The relay 60 shown in detail in Fig. 9 comprises a thin wire 78 stretched between adjustable studs 77 carried on the arms of a forked member 73, which are pressed apart by the spring 75 controlled by the screw 76. Current passing through the wire 78 causes it to expand and sag and slacken the thread 81; the spring-controlled spindle 82 is then free to rotate and moves the disk 85 so that contacts thereon and the brushes 89 complete the local circuit of the coils of the relay 57, which, when energized, maintains closed the circuits of the brake-valve magnet 99, and the whistle magnet 100, and the green signal lamp 125. The train 130, shown in Fig. 5, receives no current from the track, and its relay 57 is accordingly de - energized, and the whistle is sounded, the brakes are applied and a red lamp 129 is lighted, as soon as section B is entered. By closing the switch 139, the relay 142 may be energized and closes a maintaining circuit through the back contact 134 of the relay 57 and contacts 146 of relay 142 and a second circuit through contacts 149 to the brake magnet 99 so as to release the brakes, but the whistle continues to sound and the red lamp to glow. The train 130 must then be stopped over the wire 28, and when the advance train 138 has passed clear of section C and the relay 10 is closed, current may be supplied through collectors 63, wire 64, and back contacts of relay 57 to the relay 60, which will then close its contacts in the circuit relay 57, which by moving its armature will put the collector 53 in circuit, but since no current is supplied from the conductor 27 of block C, the relay 60 will be deenergized and thus an intermittent action will take'place until the first train has passed two clear sections ahead. The relay 57, Fig. 8, has two coils in series, and a pivoted armature 94 carrying several contacts 122 which connect either the front terminals 98 or the back terminals 58 in circuit. The valves, Fig. 14, for the whistle and brake consist of a balanced piston 112, which is connected to the core of the electro-magnets 99, 100.