BROKEN RAIL DETECTING TRACK CIRCUITS

摘要

(Case No. 6863) BROKEN RAIL DETECTING TRACK CIRCUITS Two sensor coils are positioned one adjacent each separate gage rail at the track relay end of a dual gage track section in which train detection current flows in the two gage, i. e., other than common, rails in parallel and returns through the common rail to the energy source. The signal induced in each sensor coil by this track circuit current is applied to a separate receiver broadly tuned to the track circuit frequency. The amplified receiver outputs are applied to a comparator unit which generates an output signal only when the inputs from the receivers are substantially equal as a result of equal other rail currents. The comparator output holds energized a broken rail detector relay which releases to indicate a broken rail condition in the other rails when the sensor coil signals differ by a predetermined amount. If possibility of a shunt fault between the other rails exists, the detector arrangement is supplemented by an audio frequency (AF) circuit in the loop formed by the two other rails in parallel. The comparator detects broken rails if a shunt is close to the coils while the AF detector functions to detect broken rails when a shunt is further from the coils.