Train indicator system using axle detectors - has auxiliary circuit to correct false indication due to count errors

摘要

A track indicator circuit for railways has an axle detector at a counting station (ZP1-ZP5) at the start of each track section (GA1-GA4). Coupled between successive detectors is a series of up-down counters (AZ1-AZ4) connected so that pulses from the axle detector at the start of a section of track triggers the respective counter in the forward direction whilst the succeeding detector triggers it in the reverse direction. Ideally, when a train has passed completely through a track section, the corresponding counter will have returned to zero and will give a "track clear" indication. Count errors are corrected by means of an auxiliary circuit (ZS1) which compares the count tally for a section with that of succeeding sections.