In the research authors sugested calculations of a mathematical computer modeling methods, of the operational reliability indicators for the freight diesel locomotives M62K, 2M62M, ER20CF, when transporting cargoes via the main lines of the Lithuanian railway network. According to the permissible values of the diesel locomotive reliability criteria, the maximum weights of a train
for the studied transportation lines have been calculated and a diesel engine resource has been predicted. A methodology for reducing the dynamic indicators of the operational load cycle of a locomotive diesel has been proposed and described. When applying it, a 15÷20% reduction of load cycle’s dynamic indicators (which increase the fatigue stresses of the locomotive’s cylinderpiston
group parts and components) is achieved. Technological recommendations are formulated, in order to increase the usage
of the operational reliability indicators of diesel locomotives and their energy efficiency.