THE MOST COMMON application of the process is the welding of rail sections into continuous lengths. It is an effective means of minimizing the number of bolted joints in the track structure. In coal mines, the main haulage track is often welded to minimize maintenance and to reduce excessive coal spillage caused by uneven track. Crane rails are usually welded to minimize joint maintenance and vibration of the building as heavily loaded wheels pass over the joint.
Thermit mixtures are available for all types of rail stccls. The majority of rails are C-Mn steels, but CryCr-Mo, Cr-V, Cr-Mn, and Si alloy rail steels are manufactured abroad. Addition of rare earth metals or alloys may decrease the amount of sulfur and phosphorous in the weld deposit, resulting in an improvement in mechanical properties.