Railroad correction apparatus

Track mounted apparatus for aligning railroad track, particularly curved track, comprising a first measuring system having a leading point on the track, an intermediate point on the track and a trailing point on the track and a first straight line physical reference member extending along a first chord between the leading point and the intermediate point and a second straight line physical reference member extending along a second chord between the intermediate point and the trailing point, a measuring means located between said leading and trailing points for measuring the angle between said reference members, means to move said first measuring system over a section of track and to measure a series of said angles to store them and average them thereby providing an averaged angle value;

• a track correcting means attached to and trailing said first measuring system, a track location sensing system for sensing track position values proximate the location of the track correcting means, the track location sensing system comprising a transmitter and receiver establishing a high frequency electromagnetic beam extending between two longitudinally spaced points on the track on either side of the track correcting means, the first longitudinally spaced point being forward of the point at which the angles are measured and the second longitudinally spaced point being substantially at the end of a third chord extending rearwardly from said trailing point, and a shadow board provided on a rail mounted car located proximate the location of the track correcting means, means for converting the averaged angle value to an equivalent desired radial distance from the track to the beam at the location of the shadow board, means for moving the shadow board radially towards the beam to sense the radial distance from the track to the electromagnetic beam at the location of the shadow board, and means for controlling the operation of the track position correcting means in a sense such that the radial distance of the track sensed by the shadow board substantially equals the desired radial distance thereby correcting the track alignment.