Patent GB-190510194-A (GB)
Title: Improvements in Signalling Systems for Railways and the like.
Inventor: THOMPSON WILLIAM PHILLIPS
Filed: 1905-05-15
Granted: 1906-05-03
Abstract: 10,194. Thompson, W. P., [McPhee Automatic Signalling Co.]. May 15. Stopping trains by application of the air brakes from track circuits on block system principles. Short insulated lengths are provided in the insulated track rails together with track relays and batteries ; the arrangements at a track switch in a modified form are described. The air brakes are applied when a train circuit including a dynamo driven from the train wheels and an electro-magnet t, Fig. 5, is broken. This allows a weight o on a pivoted armature m to raise the armature and its catch p out of engagement with a tooth l on a disk k. This disk is attached to a gear-wheel j of a spring motor, which actuates a plug cock w, Fig. 7, attached to the gear-wheel f. One of a series of openings 8 in the plug thereby places tne compressed-air pipe z in communication with the atmosphere, thus applying the brakes. When a train stops in entering a station, the dynamo current ceases, but the armature m is then prevented from rising and automatically applying the brakes by means of a lever, which is pressed down by the actuated ordinary throttle-valve lever upon the armature m. The track is divided into sections 2, 3, 4, Fig. 1, by the interposition of short rails 5,6 insulated from the rest of the track by joints 7, and the track rails are connected round the rails 6 by wires shown by dotted lines. A track battery 12 is connected through an electro-magnet 14 with the ordinary track rails 13, 15 of section 2, the track rails being always insulated from each other. The battery 12 is also shunted through an electromagnet 17 with the track rails of section 3, and a further shunt circuit from the battery 12 passes through the switch contacts 21, 20 of the armatures 23, 22 of the electro-magnets 14, 17, and through an electro-magnet 19. The insulated rail 5 is connected by two circuits through a switch contact 26 of the magnet 19 and the switch contact 29 or 28 of the armatures 23 or 22 to the upper track rail of section 3. If the rail 5 is disconnected from the track rail of section 3, the mutually insulated axles a, b of a train will be disconnected from each other on passing the joints 7 to enter upon the rails 5, 6 and the train circuit comprising the dynamo, magnet, and the axles a, b will be broken, and the brakes thereby applied. This disconnexion of the rail 5 occurs when trains happen to be in both sections 2, 3 or when the battery 12 fails. In the former case, the magnets 14, 17 will both be energized and the contacts 21, 29, 28, 20 all closed, but the consequent energizing of the magnet 19 will break the contact 26 and thereby insulate the rail 5 from the track rail of section 3. If the battery 12 fails, the contact 26 remains closed, but the armatures 23, 22 will remain unattracted and the rail 5 will remain insulated from the rest of the track. The system may be similarly applied to stations where a track switch 49, Fig. 2, exists, and the switch - operating mechanisms 50, 51 are arranged to connect the rails of the section 47 when the switch is thrown in at either end, thus acting on the system as if a train were present in the section 47. In addition to the usual circuits described above, a track battery 37 is included in a circuit with electromagnets 38, 39 at stations 34, 35, the circuit being completed from the magnet 38 to a contact 40, armature 41, contacts 42, 43, to the rail 13, and so to the station 35, the armature 22, contact 28, and the magnet 39. The armatures 41, 23 at the station 34 move together on the same pivot but are mutually insulated. Two trains arriving at the stations 34, 35 from opposite directions will as usual energize the magnets 14, 17 respectively at these stations and thus complete the circuit of the magnets 38, 39, which attract their armatures 44, closing a circuit across the rails of section 47 through contacts 45 and wires 53, 54. This again acts as if a train were in section 47, stopping the trains at the stations 34, 35. The circuit of the battery 37 may be broken for predetermined time intervals, say when the telegraph operator is on duty, by the introduction of a clock 55 operating time switches.