Abstract: A manned welding and inspection vehicle for working within the interior of a pipeline or the like, the vehicle including two annular seals for aligning the vehicle in the pipeline and for sealing portions of the environment about the vehicle. The vehicle also includes an automatic welding system, the welding head of which is located in the front end of the vehicle and capable of welding a 360.degree. arc. The welding head also includes a fine adjustment mechanism to compensate for misalignments. Driven by the engine of the vehicle is a driving mechanism which is rugged and compact, and a fan for creating the proper air flow around the vehicle without disturbing the air flow at the welding site.