In the article the author notes that the horizontal forces arising in the process of pressing the wheel flanges to the working edge of the rail, under certain conditions can be very significant. These forces, in combination with the wheel unloading, caused by the geometric deviation of the track in the plan and profile, can lead to rolling the wheel of the wheelset onto the rail head and, as a consequence, to the stock derailment.
Such pressing of the wheel to the rail head in the straight part of the track can occur when faults in the running gears of the wagons: non-parallelism of the axles of the wheel pairs of the bogie frame by the difference in the bases of the side frames, wear of the guide axle-box openings; the difference of the flanges on one wheel pair is more than permissible, wear of the body and bogie bolster center plates, step bearing; a significant difference in the diameters of the wheels of the wheelset caused by the intense wear of the rolling surface of one of them, etc.
The article deals with the investigation of the influence of the wheels’ diameters difference of the wheelset on the amount of lateral force for the empty and loaded state of the rolling stock wagon.
The results obtained made it possible to conclude that an increase in the wheels’ diameters difference of the wheelset of a loaded wagon of rolling stock leads to more intensive growth of the lateral force, as compared with the exhaust. This is caused by the linear dependence of the lateral force on the mass of the wagon of the rolling stock.
However, for both the empty and the loaded wagon, the increase in the lateral force value has a negative effect. In conjunction with the unloading of the wheel it increases the probability of rolling in the wheel of the wheelset on the rail head. Also, an increase in the action of the lateral force from the wheelset on the rail, causes increased wear of the rail, the wheel flange, which is pressed. At the same time, rolling surfaces of an irregular shape are formed on the surface of the other wheel.
Therefore, it is important to ensure the maintenance of the wheels of a wheel pair with the smallest difference in its diameters.
Key words: rolling stock, diameter difference of wheels, quasi-dynamics method.