The article analyzes the main tasks of ensuring the efficient use of rolling stock, approved by the Government of the Russian Federation in the strategic program for the development of railway transport until 2030. One of the key tasks in this field of activity is to increase freight turnover within the country and beyond due to the modernization of the fleet of freight main locomotives and the reconstruction of individual sections of the railway. In this regard, the results of a comparative analysis of two series of locomotives - 3TE25KM and 3TE10MK according to the main technical characteristics are proposed for consideration, main indicators of the operational work of diesel locomotives that affect the amount of cargo turnover are described. The implementation of the cargo turnover plan of the Far Eastern northern latitudinal railway is analyzed - these are Komsomolsk-na-Amure-Volochaevka II and Komsomolsk-na-Amure-Sovetskaya Gavan. In conclusion, results of testing a new locomotive are presented, based on their technical and economic characteristics, such as the amount of work performed, technical speed, average daily productivity of the locomotive and a number of other indicators.