Scientific paper ID 2741 : 2025/3

One of the main tasks facing the rolling stock of the Bulgarian State Railways is to increase the operational reliability. The goal is to ensure the safety of train movement, improve operational performance, increase the axle load and speed of movement. Increasing the economic efficiency in the operation of the rolling stock can be achieved by using the method of replacing and repairing the units and aggregates according to their actual technical condition. This method will allow the relevant units and aggregates to continue to be in operation after the expiration of their specified resource, taking into account their real technical condition. The axle boxes and the rolling bearings installed in them largely determine the operational performance of the rolling stock. It is known that their failures in operation lead to emergency situations. The technical condition of the bearings in a given unit depends on many factors characterizing the quality of their manufacture, their normal lubrication, the conditions and mode of operation. There is a need to analyze the factors influencing the occurrence of malfunctions in the elements of the axle box roller bearings. This article determines the loads acting on the elements of a standard freight wagon axle box. The permissible horizontal load on a radial roller bearing is determined. The dynamic and equivalent load of an axle box bearing is calculated and the resource of an axle box bearing of a freight wagon type Y25, in operation of the Bulgarian State Railways, is determined.