| 摘要 |
1,235,809. Train control system. GENERAL SIGNAL CORP. 3 Dec., 1969 [6 Dec., 1968], No. 59012/69. Heading B7N. [Also in Division G3] In an arrangement for automatically controlling a train 10 to a halt at station platform 11, pick up coils 16 on the train receive a track signal from unit 13 having a frequency which is a function of the distance to stop and this signal is applied with a signal from axle driven generator 14, having a frequency proportional to train speed, to a control circuit providing an output E for controlling train brake and speed control equipment 17. The track between unit 13 and the leading axle of the train forms a variable inductive element which controls the frequency of an oscillator circuit in the unit, which thus supplies a signal to the track rails having a frequency inversely proportional to the root of the distance to stop. A voltage analogue of this signal is provided by unit 18 and supplied to a multiplier 20 which receives as second input an analogue of the speed signal supplied from generator 14. If the train is decelerating correctly the product signal should be constant and to obtain this condition the product signal is applied with a fixed voltage K2 to a difference circuit 21 which supplies via an integrator circuit 22 the controlling error voltage E. By connecting the unit 13 to the rails at the point braking is to commence and by providing the coils 16 at the end of the train, the frequency of the picked up signal can be directly related to the distance to go. |
