<p>The study highlights the factors affecting the basic reliability indices of special self-propelled rolling stock (SSPRS), rail service cars and rail inspection cars, such as mean time to failure, the probability of failure-free operation, the failure rate, gamma-percentage resource. Methods for their determination are indicated, their quantitative assessment is made. It is shown that individual units of electromechanical equipment working in conjunction with an asynchronous motor, clutches and actuators have a superimposed exponential and normal law of probability distribution to failure. The formula to determine the distribution density,which is necessary to adjust the SSPRS reliability is described.</p>