Abstract: The specification discloses a method and apparatus for assuring the integrity of outside weldings of pipelines. Pipe sections are prepared for welding by forming a beveled profile with a relatively narrow annular contact band on the ends of each pipe section. When the pipe sections are abutted end to end for welding, the leveled profiles form a relatively deep groove on the outside of the pipe between the pipe sections, with the annular contact bands abutting and spaced inwardly from the grooves. The contact band on at least one of the pipe sections is circumferentially prepared such as by knurling to provide controlled spacing between the contact bands of the pipe sections. A welding arc is applied to the bottom of the groove from the exterior of the pipe sections to weld the annular contact bands together. Welding penetration is enhanced by the circumferential preparation of the contact bands.

Abstract: Apparatus is disclosed for transporting heavy equipment such as welding current generators, a prime mover therefor, and associated devices or supplies, on and along a pipeline, the pipeline serving as a monorail. The apparatus, of elongated construction along the pipeline, is supported at one end and propelled along the line by power driven traction means engaging the top part of the pipeline. The opposite end of the apparatus is supported on a pair of laterally spaced swivel mounted wheels which engage the sides of the pipeline laterally away from and somewhat below the top of the line. The latter wheels give lateral support and stability to maintain the apparatus in a substantially upright position on the pipeline. Sensing means, such as a pendulum, mercury switch means, or equivalent, detect incipient tilting or motion towards instability and are used to steer the swivel mounted wheels, either directly or indirectly.