One of the conditions without emergency operation of a diesel locomotive and ensuring strict compliance with the train schedule is the maintenance of diesel locomotives in good technical condition, constant monitoring of the operation of the most critical units and devices with timely elimination of malfunctions, that is, proper maintenance of the diesel locomotive in operation. Hence, there are special requirements for the used detergent when washing its components and assemblies. The use of environmentally friendly and safe flushing agent «АРС-20» provides high quality flushing absolutely at all washing and degreasing operations of diesel locomotive units and assemblies, especially when flushing electromechanical equipment. Special requirements for the used detergent when washing wheelsets, fasteners, axleboxes, units and bearings before disassembly,repair and defect detection, since the presence of soda deposits, when using traditional detergents, will lead to corrosion and, in the future, to intensive wear of components and assemblies during operation. The use of "ARS-20" gives a high quality of washing of all units and assemblies of the locomotive, and does not contribute to further oxidation, does not cause corrosion of the washed surfaces.