Patent GB-216641-A (GB)
Title: Improvements in or relating to train signalling and controlling apparatus
IPC: B61L3/08
Filed: 1923-04-17
Abstract: 216,641. Robson, H. April 17, 1923. Electrical systems, automatic; track apparatus for stopping trains and actuating signals on, and other than on, trains: audible signals; indicating movements of trains; indicators. -In a train-controlling or signalling system for railways a track device is provided which may be operable by a passing train as an electric switch, or may serve as a ramp for operating train-carried signals or brakes. A spring arm 2 forming a displaceable ramp co-operates with a shoe 50 on the train. A spring-elevated plunger 3 when depressed by member 2 contacts with a plunger 7 closing an electric circuit. The plunger 7 is raised by a spring, not shown, and may be locked in its raised position by the armature 12 of an electromagnet 11. Figs. 1, 3, 4, 6 show the invention applied to a semaphore signalling system. With the semaphore 17 in its normal danger position, the plunger 7 is locked against depression. A circuit is provided from lead 41 through an indicator magnet 36 in the signal cabin, switch 25 controlled bv the semaphore, lead 44, to the plunger 7. When the ramp 2 and plunger 3 are depressed by the shoe 50 of an oncoming train, the circuit is completed from the plunger 7 through the plunger 3 to earth. The armature 34 of the magnet 36 is attracted, releasing a rod 31 which falls, displaying a " train at signal " indication to the signalman, and at the same time closing contacts 32, 33 in the circuit of a horn 46. An audible signal is thus given to both driver and signalman. The arrangement may also serve as a warning to platelayers &c. As the plunger 7 is locked against depression, the plunger 3 after a limited depression serves as an abutment raising the shoe 50. This raises a rod 53 and operates a valve 52 venting the train-pipe and applying the brakes. The whistle 56 may also be operated. The valve is reset by means of a handle 55. The rod 31 of the indicator is replaced by hand. The circuit of the horn 46 may be closed independently by a press-button switch 39 to signal to the driver. When the signal is at clear, the circuit through the indicator magnet is broken at the switch 25 and a circuit is closed thereat from the lead 41 through the magnet 11, the armature of which is attracted, releasing the plunger 7. Under these circumstances, both plungers 3, 7 are idly depressed by the oncoming train, and the shoe 50 is not operated. Figs. 7, 8, 9, 11, 13 show the invention applied to a system for automatically preventing a train from following another into an occupied section. In this arrangement three track switches A, B. C are provided, only one of which is provided with a locking device for the lower plunger 7, the plunger being normally unlocked. The first train travelling from left to right idly depresses the plungers of the switch A. On reaching the switch B the train depresses the plungers 3, 7 closing a circuit from the lead 41 through lead 84, relay magnet 58, lead 86, plate 69 on a switch arm 65, bridging contacts 70, lead 87 to the switch B. The relay is of known type in which a pivoted plate armature 61 is thrown over from one side to the other at each momentary energisation of the magnet 58, and gives corresponding movement through a link 64 to the switch arm 65. The above energisation of magnet 58 throws the switch arm 65 to the right, breaking the circuit of the magnet 58 at contacts 69, 70, and closing two circuits from the lead 41, through switch arm 65 and contact 66, one circuit being through the lead 89 and magnet 11 of the switch A, locking its plunger 7 against depression, the other circuit being through the lead 92 and magnet 72 of a position indicator on the signal cabin, the armature of which allows a disc 77 to fall displaying the indication " train in section." The indicator is reset by a hand-operated rod 78. When a following train reaches the locked switch A, the shoe carried by said train is operated to apply the brakes &c. As the first train passes device C at the exit end of the section, depression of the plunger 3, 7 closes a circuit through the magnet 58, thus throwing the switch-arm 65 to the left and restoring the arrangements to normal condition. A number of indicators may be provided in a single casing, and reset by a common rod 78. Fig. 14 shows a wagon brake arrangement in which a brake arm 94 of usual type is held raised by a pivoted member, not shown, and is released to apply the brakes when a shoe 50 is raised by a ramp 2. To remove the brakes in a train of wagons a cable 102 is provided, tethered at one end 103 of the train, and carried through loops or links 104 on the arms 94 to a winch at the other end of the train. Normally, the cable is slack, but when tightened bv the winch, the brake arms 94 are raised and are individually retained by their pivoted catches.