a mobile arc welding machine that moves across the surface of the workpiece along the edges being welded or on a light, portable rail track. The welding head is equipped with a mechanism that feeds the electrode wire through a holder to the location of the weld. The head is mounted on a transport carriage together with a reel of electrode wire and a control panel. Self-propelled welders are part of the equipment complement provided for automated welding stations. Other equipment includes a source of welding current, control apparatus, and accessories.