Abstract: Apparatus for end-to-end alignment of first and second sections of pipe for the welding together thereof including a frame assembly carrying independently expandable and retractable first and second axially spaced clamps for engagement and disengagement with the interior walls of said pipe sections. The frame assembly also carries a drive assembly by which the apparatus is propelled through said pipe sections and a brake assembly to slow or stop movement of the apparatus therein. Controls are connected to the clamps, the drive assembly and the brake assembly which are responsive to sensing of the end of the first pipe section by a sensor to deactivate the drive assembly, activate the brake assembly, arrest movement of the apparatus and, upon predetermined alignment, to activate the first clamp and finally the second clamp for engagement with the walls of the pipe sections.