Railway track control system - has wheel passing between receiver and transmitter coils for three pulses

摘要

A track control system employs a pulse transmitter associated with a low impedance coil on one side of the track and a receiving device with a similar coil on the other side, the latter actuating a signalling relay when a wheel passes between the coils. The transmitter is fed by a continuous low power electric supply and a circuit which generates short high power pulses. This circuit includes a thyristor controlled capacitor charging arrangement, and the discharge circuit includes a thyristor controlled by pulses fed by the low power source. The pulse frequency is regulated so that when the vehicle passes at a maximum speed, each wheel occupies the space between the coils for a period of three pulses.