The internal combustion floor toothed railway SKZ-81 is intended for transporting heavy, large sized machines and equipment, as well as people in underground mine headings. Its characteristic feature is that it uses existing tracks in the mine, supplemented only by a toothed bar placed centrally between the rails on sloping sections. This solution makes it possible to transport heavy loads without transhipment, and thus to reduce the time and costs required. The railway can be used in spaces with a, b or c methane explosion risk, and A or B coal dust explosion risk.