Apparatus for continuously surveying and aligning railroad track has a measuring system with a leading point and a trailing point, both points being on the track center line. Two tensioned wires extend between these points, respectively, and a common intermediate point also on the track center line. At the trailing point a shadow board is located and this is arranged to interrupt an infrared beam extending between a projector at the leading point and a receiver behind the trailing point. A device measures continuously the angle between the two wires and this value is averaged and then subjected to mathematical manipulation in a computing device to derive an ordinate value for the shadow board which is automatically extended accordingly. The receiver then commands a track correction ram located adjacent the shadow board to move the track radially inwardly or outwardly until alignment between projector, receiver and shadow board causes the receiver to stop the lining action.