Abstract: A machine for welding rail comprises a rail vehicle with at least one energy generator set, a programmable automatic control unit and a raised chassis disposed between the bogies of the vehicle. The chassis supports at least one welding unit, grinders, two workbench units, each comprising a beam equipped with grippers for gripping, lifting and holding the rails in a working position, a set of grippers at the ends of the vehicle, and position sensors.

Abstract: A process and vehicle for automatically screwing and unscrewing tie screws performed by the vehicle moving continuously along a track. This invention makes it possible to detect and determine the relative position of a tie screw with respect to a tie screw fastening head by optoelectronic devices and to set, if appropriate, the inclination of the tie screw fastening head. The tie screw fastening head is positioned above the tie screw and a tie screw fastening cycle is engaged for each tie screw. The tie screw fastening heads then hop from one work position to another, performing this process.