Patent GB-131923-A (GB)
IPC: B61H11/00
Abstract: 131,923. McKenzie, Holland, & Westinghouse Power Signal Co., (Assignees of Lewis, L. V.). March 4, 1918, [Convention date]. Electrical s y s t e ms, automatic; track apparatus actuating signals on trains. - Apparatus on trains is controlled by induction from the track rails, which are supplied with alternating currents of one frequency and are used as part of the track relay circuit as usual, the relay current flowing in opposite directions in the two opposite rails, and current is also supplied through the two rails in multiple so that it flows in the same direction through the opposite rails. The locomotive carries two coils for energizing one coil of the signal-controlling relay in accordance with the current flowing in the track relay circuit. and the other coil of the said relay is controlled by a second pair of coils wound and connected so as to 'be energized by currents flowing in the same direction in the opposite rails. This latter current is reversed or cut off by track relays according to the conditions of the track in advance. The drawing shows two blocks A-B, B-C each provided at the point E with a reactor M which serves to divide each block into a front and rear section. Track relays H<a>, H<b>, H<c> are supplied through the rails in series as usual with current from transformer secondary 3 at the forward end of the section through the two windings of the reactor W in series. When the relay Hb is energized, the rails through the whole of the block A-B are in parallel in a circuit including the transformer 18, contact 20, resistance 22, two halves of reactor M, the rails R, R<1>, two coils of reactor W, two pairs of transformer 3 in parallel, and contact 9. This current is of the same phase as the track relay current. The relay H<c> being de-energized, its contact 9 is opened, and a current of reversed phase passes by way of armature 20, reactor M, rails R, R<1> as far as the point E, reactor M at E, and resistance 11. The section E-C does not receive current in parallel in the rails when the section in advance is occupied. Each train carries two coils 26, 26a in series with a condenser 30 in a tuned circuit, these coils being wound and connected so that current is induced in them by currents flowing in reverse directions in the opposite track rails. By means of the electron amplifier K', the coil 55 of the two-coil motor relay F on the train is energized. Two other coils 27, 27<a> are connected to a condenser 35 and are wound so that the potentials induced therein by currents flowing in the same direction in opposite rails energize the amplifier K<3> and the relay coil 59. Hence under the conditions shown, a train V<1> being in advance of the point C, the apparatus on the train V causes current in both coils to be of the same phase, and a clear signal is energized while the train is in section A-B. After passing the point B, the phase of the current in the coil 55 is reversed since the current in the rails of the portion B-E in parallel is reversed, and the relay F is reversely energized while the train is in the section B-E. Since no current in parallel passes in the rails of the section E-C, the relay F becomes de-energized when the train V enters this section of track. The form of the electron relays or amplifiers is described in Specification 124,201.