Apparatus for use in correcting the position of railroad track including an elongated vehicle carrying means responsive to a variation in electric current, at least one elongated rigid member extending forwardly from the vehicle and pivotally supported thereon and a second vehicle pivotally supporting the other end of the member for movement along the track. At least one variable resistor attached between the member and the elongated vehicle and connected in a bridge circuit with the means responsive to current variation so that angular displacement of the elongated vehicle and the member in at least one plane from a preset relationship varies the resistance of the variable resistor effecting a response by the means responsive to current variation.