Patent GB-322197-A (GB)
Title: Improved signalling means for use on railway and like tracks
IPC: B61L13/00
Filed: 1928-05-31
Abstract: 322,197. Neale, J. May 31, 1928. Wireless systems; track apparatus actuating signals on trains and other than on trains; visual outdoor signals. -Signals and train-stopping means are controlled bv the obstruction of rays from a lamp 1 to a light sensitive cell 2, which is preferably of the type claimed in Specification 284,942, [Class 40 (iii), Telegraphs, Electric]. The electriclight-sensitive unit 1, 2 may be carried on a vehicle to control apparatus thereon when a shutter 8 on the track is passed in operative position or it may be placed on the track and control apparatus when train wheels, or other parts of vehicles, pass by. The lamp and sensitive cell are arranged in tubes 3, 4 to shield the cell from any extraneous sources of light. Fig. 5, shows parts of five sections, at the entrance to each of which a light-sensitive unit B<4> - - B<7> is placed and connected in series with a relay R<4> - - R<7>. A train entering the section T<6> obstructs light from the cell B<6> and opens the circuit to the relay R<6> of which the contact M<6> is opened and contact N' closed to energize the coil V<6> of a two coil relay and reverse its armatures to the position shown, and break the circuit through the coil V<6>. The closure of contact P<6> resets the relay R' of the rear section and completes the bridge circuit. Contact D<6> opens the circuit to the switch C<5> which opens the power circuit to the section T<5> and to one magnet in each signal S<5>, S<6>. The signals, Fig. 11, are operated by a thrust rod 42 attached to a floating- lever 41 operable by the cores of solenoids 39, 40 both of which must be energized in order to set the arm to clear. The resetting of relay R<5> closes contact D<5> to energize switch C<4> which recloses the circuit to one coil of signal S<4> which would be set to clear if no train had entered the section. An arrangement for controlling speed of trains over a particular section of tracks, Figs. 8 and 9, comprises an electric-light-sensitive unit J and one or two shutters K, L, arranged to be raised by electromagnets at predetermined intervals after passage of the train past the unit J. De-energization of the relay 44, as the train cuts off light from the sensitive cell, closes contacts 45 in parallel with the contacts 28 of the holding relay 27 in series with the heating-coil 22 around a bimetallic strip 21. After a given time the strip flexes to open the circuit to the heating coil and close the circuit over contact 24 to the magnet which raises the shutter K which if the time interval is less than the time taken bv the train to reach the shutter, will serve to initiate a brake application. According to the first and third Provisional Specification beams of light may be projected longitudinally of the tracks to impinge upon cells on trains moving along the tracks. According to the second Provisional Specification the switches in the system shown in Fig. 5 may be mercury switches and the light beam may be refracted and only the infra-red rays employed, or the infra-red rays may be used in fog as an alternative to the visible rays. According to the third Provisional Specification detonator apparatus may be controlled by a train passing a light-sensitive unit including a lamp switched on either manually or automatically by an auxiliary sensitive cell and a sensitive cell controlling detonator-firing mechanism, and a beam of light which may be infra-red, from the rear end of one train may be received by a sensitive bridge on a following train. According to the fourth Provisional Specification, audible signals on the track may be controlled by a relay of the type described in Specification 304,618, [Class 38 (v), Electric switches &c.], or an audible signal on the train may be operated by a lamp on the track and a sensitive cell on the train. According to the fifth Provisional Specification means for controlling the speed of a train comprises means at one point of the track for illuminating a lamp at a known distance ahead and a sensitive bridge on the train which will apply brakes if the lamp is alight when the train passes it, or, a lamp on the vehicle causes a sensitive bridge to put in operation delay-action relays as described in Specification 321,671, [Class 40 (v), Wireless signalling &c.].