Railroad track monitoring and adjusting device

Abstract From the Canadian patent

A track aligning device for monitoring the curvature of a track and adjusting the track successively to correct the curvature incorporates two taut wires mounted on a car or cars running on the track the wires each, defining two chords each extending between a pair of spaced points located on the track center line. Preferably the cords overlap. Each chord operates as a reference line which cooperates with a respective measuring device. A first measuring device located nearer the rearward point of the first chord derives a voltage which is sampled at equal intervals say 2 meters, as the, aligning device passes along the track. The voltages are summed and averaged electrically and a voltage …