Patent GB-180757-A (GB)
Title: Improvements in and relating to the control of railway trains
IPC: B61L23/12
Filed: 1921-03-01
Abstract: 180,757. Underwood, W. J. March 1, 1921. Electrical systems, non-automatic; track apparatus for stopping trains.-In electric signalling systems for trains running in both directions on the same track, or for a number of trains converging to one track, a separate electrically-controlled device at each danger point is normally set against trains passing; separate, controlling-switches are provided for each device and have central neutral positions from which one is moved in one direction to close the operative circuits which clear the line signals, provided that all the other switches have been moved in the opposite direction to close their tracks aganst trains passing their points. In Fig. 1 a single track C is shown with double tracks at the stations A, B. The rails 1, 2 of the single track are electrically continuous and are insulated from the adjoining portions by insulation D', D<2>, E<1>, E<2>. Trains travelling from left to right stop at the station A upon the track 3 while trains in the opposite direction stop at the station B on the track 4. Track devices 5, 6 are provided at the stations and they normally assume the danger position in which they engage apparatus on the locomotive to stop the train. Manually-operated switches 9, 10 at the stations A, B respectively, have weighted arms which set in the neutral position when free, and have fixed contacts connected to the coils 7, 8 of the track trips, the locking-coils 46, 53 of the point levers 47, 54, the operating-coils 15 of the signals 13, 14 to the batteries 11, 12 and to the rails of the single track C. The point levers are locked while the coils 46, 53 are not engaged. Switches 49, 57 are operated by the movement of the respective point levers 47, 54, and the levers can only be moved to operate the points when the locks are released by the closure of the switches 44, 52 by the removal of the track trips from the danger position. When a train is waiting on track 3 at station A, the signalmen communicate with the man at station B in the usual manner, and if they agree to pass the train on, the switch 9 is moved to position I. and the switch 10 to position II., the points at station B being in the position shown to receive a train from station A. A current then flows from the battery 11 through contacts 21, 23, coil 7, wires 31, 41, pointoperated switch 57, contacts 39, 38 of switch 10 and track rail 1 back to the battery. The trip 5 thus moves into the safety position and also closes the switch 44, thereby releasing the lock 46 on the point lever 47 which can then be moved to set the points at the station A for the train to proceed. The movement of the points closes the switch 49 to energize the operating-coil 15 for the signal 13. The signalmen must hold the switches 9, 10 in positions I., II. respectively until the cab of the engine has passed the signal as the position of the signal is dependent upon the trip coil 7 remaining energized. Ammeters 60, 61, 62, 63 connected in the leads at the sides of the batteries 11, 12 give indications to the signalmen of the progress of events. If the switches are held closed after the train has entered the track C, the train short-circuits the battery, causing the trip 5 and the signal 13 to return to danger position. The action in passing a train from the station B to station A is similar to that described above, but the switch 10 is moved to position I. and the switch 9 to position II. With this arrangement of switches only one of the coils 7, 8 can be energized at any one time. In a modification the switches 9, 10 are used to control the signals directly instead of through the track trips. Or a bell in the stationmaster's office may be operated from the switch 9 and a switch may be placed there to control the signal. The switches in another modification control coils which operate the valves of a pneumatic motor actuating the points. In another modification three tracks F, G. H, Fig. 5, are shown converging to a single track D. The sections of rails of each track near the points are insulated from the remainder by insulation EF, Ef &c., &c. Within the insulated sections the rails on one side of each track are connected together, and the rails on the other side are connected together. The connected systems are shown as single rails 1, 2 in Fig. 4. Each track has a track trip coil 7f, 7g, 7h, and switches f, g, h, connected as shown. Each switch may be connected with a separate battery as shown in Fig. 4, or to a common battery as shown in Fig. 5. To pass a train from track F to the junction, the handle of switch f is moved to the right and those of switches g, h to the first left hand position. To pass a train from track G, the switch g is moved to the right, switch f to its first left-hand position, and switch h to its second negative position; while to pass a train from track H switch h is turned to the right and switches f, g to their second left-hand positions.