Analysis of Influence of Disturbing Signals Caused by Rail Magnetization to a Cab Signaling System

摘要

The Automatic cab signaling system ALS is a road and cab equipment designed to transmit information about permissible train speed to a cab driver. ALS equipment makes train control easier, controls actions of a cab driver, limits train speed and, if needed, stops the train. It also logs actions of a cab driver, train speed and other parameters. The signaling system used in Lithuania is the uninterrupted automatic cab signaling system ALSN. The ALSN equipment transforms traffic-light signals into a code - a combination of modulated pulses with 25 or 50 Hz alternating signal as a carrier. Pulses of current are transmitted to rails in front of a train and induce proportional electromotive force in pick-up coils of a cab. After signal processing and decoding, a respective signal is turned on in a cab dashboard. Code information is also used to control cab brakes in case train speed exceeds allowed by traffic-light signal. During code generation, transmission and reception, disturbances occur. In case of wrong detection of codes, equipment of cab limits the train speed or even stops the train.