The issue of selecting rational sizes (capacity) of mine cars for underground transportation has been discussed in the domestic mining literature for twenty years. In the first period of development of mechanization of mining industry, when our plants were just starting to master the serial production of cars and electric locomotives, it was necessary to set the problem and its solution, which could provide answers to the questions put forward by designers about what should be the main dimensions of the cars designed by them. Attempts to solve the question in this plane were reflected, for example, in the works of A. V. Nekoz and A. I. Milovanov. Later, when the serial production of several types of carriages and electric locomotives was mastered and the unification of carriages was carried out, which established a certain minimum of their standard sizes, there was a need to solve the question of choosing the size of the carriage in a different plane. Now this question began to be put forward not by designers, who by that time had created a number of standard cars and thus basically fulfilled their task, but by design engineers. They were interested in another question: how to choose the most favorable one for the given operating conditions from among the available standard cars.