Abstract: Apparatus for detecting at least one metallic object in a series of metallic objects lying along a path in a repetitive pattern by a metallic detector mounted on a vehicle movable along the path with the movement of the vehicle controlled by the detector to position the vehicle over a detected metallic object and blocking detection of a previously detected object subsequent to the detection of the previously detected metallic object to prevent erroneous metallic object detections, and further controlled to initiate different travel modes of movement including a fast mode to move the vehicle in a forward direction along the path at an optimum speed and controlling deceleration of the vehicle for accurately positioning it at a detected one of the metallic objects. The apparatus has particular application to the tamping of crossties on railway tracks and includes programs for controlling the movement of the vehicle and the tamping operation.

Abstract: An electronic levelling apparatus using an inclinometer mounted to a platform for sensing deviations from the horizontal and generating an output signal representative thereof, filtering the inclinometer output signal to remove electromagnetic and radio frequency interference, level-shifting the filtered inclinometer output signal to establish both positive and negative threshold voltages, determining positive and negative voltage level shifts to generate a level control signal therefrom and transmitting the level control signal to an actuating mechanism for maintaining the platform level.