a machine that electromechan-ically welds rails into long sections that are set into a jointless track. There are stationary rail-welding machines, which operate in specialized rail-welding plants, and mobile rail-welding machines, which operate in the field.
Under stationary conditions rails are welded on a production line, which includes machines that straighten bent rails, remove bumps, and cut off defective portions, an are-welding machine, and devices that mechanically and thermally treat and check the quality of joints.
Mobile rail-welding machines are mounted on tetraxial platforms. Two U-shaped tilting frames, each with a boom, are installed on a platform. Two telphers, each with suspended are-welding heads, move along the lower beams of a boom. The heads receive a current of 200 kilowatts from a power unit that is installed at the end of a platform. There are three hoists for moving rails. The welding time is about 160 sec, and the upsetting force is 350 kilonewtons (35 tons-force).