Patent GB-124201-A (GB)
Title: Improvements in Railway Traffic Controlling Systems.
IPC: B61L3/22
Filed: 1919-03-03
Abstract: 124,201. McKenzie, Holland, & Westinghouse Power Signal Co., (Assignees of Lewis, L. V.). March 4, 1918, [Convention date]. Electrical systems, automatic; track apparatus actuating signals on trains.-Alternating currents supplied to insulated rail sections and sections of an auxiliary conductor are controlled so that the relative phases differ according to the existing traffic conditions in advance and induce currents in train-carried coils which interact to control signal circuits on the train. The currents are all of the same frequency, and the controlling devices, which are dependent upon track relays, serve to cut out or reverse the phase of the supply to either the track rails or the auxiliary conductor. Fig. 2 shows two blocks of track A-B, B-C with insulated rails and an auxiliary conductor X divided into two portions in each block at the point E. The rear sections AE, BE are supplied constantly from the secondaries 75 of transformers T<a>, T<b>, by a circuit including the resistance 87, reactor M, the rails in multiple, and another reactor M. The forward sections E-B, E-C are supplied from the transformer 78<b>, 78<c> at the advance end through the reactor W so long as the track relay J<b>, J<c>, connected to the advance block is energized and the currents in the two sections of the auxiliary conductor are in phase. The track rails are supplied from transformers 71<b>, 71<c> through the coils of reactor W in series, and under control of the track relays of the advance blocks which have two windings, one 66 constantly supplied and the other 65 connected to the track rails. A train V<1> in advance of the point C shunts the relay J<c>, and the armaturel 69 of this relay connects the transformer 71<c> to the right coil of transformer T<c> which supplies current of reverse instantaneous polarity to the track rails and track relay Jb. The armature 70 of relay J<c> cuts off the supply to the conductor E-C. Armature 69 of relay J<b> supplies current of normal polarity to the track rails A-B, and armature 70 energizes conductor E-B similarly. Each train carries two coils 26, 26a in series with a condenser 30 in a tuned crcuit, 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<1>, the coil 55 of the two-coil motor relay F on the train is energized. A coil 27 in inductive relation to the conductor X similarly controls the coil 59 of the same relav. Hence under the conditions shown, the apparatus on the train V causes current in both coils to be of the same phase, and the clear signal G is energized while the train is over conductors A-E, E-B. After passing the point B, the phase of the current in the coil 55 is reversed since the current in the track rails BC is reversed and the caution signal Y is shown while the train is over conductor B-E. The conductor E-C being deenergized, the coil 59 becomes de-energized when the train reaches this conductor, and the relay F puts the danger signal R in action. A set of signals on the track G', Y', R' are similarly controlled by the armatures 68 of the track relays J<b>, J<c>. A modified arrangement of apparatus on the train includes a second electron amplifier in the circuits between the coils 26, 26<a>, 27, and the coils of the relay F. A modified system of track connexions is described in which the track rails are constantly supplied and the currents in the rear portions of the auxiliary conductors are reversed in phase, and the forward portions are supplied with one phase only, or are de-energized according to the state of the track in advance. In a further modification of this system, the advance portion of the auxiliary conductor of one section is connected in series with the rear end of the conductor of the advance section under control of the track relay; this system provides an overlap of adjacent sections. The Specification as open to inspection under Sect. 91 (3) (a) comprises also a system in which the auxiliary conductor is dispensed with, and the track rails 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 of a different phase is supplied through the two rails in multiple so that it flows in the same direction through the opposite rails. The locomotive carries two coils, as above described, 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. This subject-matter does not appear in the Specification as accepted.