Abstract: This invention relates to a convertible road/rail power vehicle including a tractor unit provided with retractable wheel sets and rail equipment that enable it to be operated on either highways or railway tracks and when on rail to pull a multiplicity of loaded or unloaded railway cars.

Abstract: A method and apparatus for marking a line, such as the centerline, along a roadway, using a vehicle carrying paint marking apparatus, in which a pair of television cameras, one mounted on each side of the vehicle, view the edges of the roadway and project the images onto a split screen. By keeping the images on the screen in a predetermined relationship the operator can steer the vehicle in a path along the roadway uniformly spaced from its edges. Preferably a third camera, centrally located on the vehicle, views the vanishing point of the roadway when straight and the image of the vanishing point is registered with a predetermined mark associated with the screen.