The Thermit wide gap (75mm) welding process has been developed to replace defective welds (Alumino-Thermic, Flash Butt or Isolated Rail Defects). This eliminates the need to install a fresh length of rail, usually by welding on both ends.

The procedure involves removing the defective weld, aligning and creating a gap of 75mm ±2mm between the rails and fixing the requisite wide gap prefabricated mould around the rail gap. The remaining steps are same as the regular SKV technique. The time for preheating the rail ends are as follows: