The operating mode of traction motors of mine electric locomotives is poorly studied. There is no theoretical justification for the selection of traction motor power to a given locomotive weight. In the USSR and abroad the ratio of engine power to locomotive weight is taken differently by different plants and firms. American companies, for example, for 1 t of locomotive weight take engines with power from 6.95 to 8.76 kW, West‑German – from 4.62 to 6.57 kW, plants of coal machine building in the USSR – from 5.88 to 6.57 kW. Thus, American electric locomotives have a higher specific power. Increasing the specific power of an electric locomotive guarantees traction motors from possible overloads. This is a positive factor. If the forces of resistance to the train movement exceed the traction force provided by the adhesive weight of the locomotive, the driving wheels will start slipping and there will be no further increase in the power consumed by the engines. At the same time, automatic limitation of the loading of traction motors will be provided by the value corresponding to the electric locomotive adhesive weight.

The methods of energy consumption determination existing in the practice of underground electrified haulage do not take into account some peculiarities of electric locomotive operation. The survey of coal and oil shale mines in a number of basins has established that when an electric locomotive is operating, the energy is additionally (unproductively) spent on abrasion of wheel tiresand rail heads during slipping, in rheostatic resistance and increased losses on heating of engines. This energy consumption is especially high on the complex longitudinal profile of the haulage tracks.