Here is presents contemporary methods of investigation of the effect of rotation on the durability of the axle assembly, the real dimensions of fatigue the city radius of the transition part of the railway axle behind the seats, wheel hub. Here are occurs the greatest pressure force fact of external loads and solid swept by pulling a point on the shaft. According to this method only focused on examining the work of the transition radius axle behind the seats, wheel hub. The aim of the quantification of the impact of fatigue on the axis of rotation that can help increase the lifetime axle assembly and quantitative calculation of the impact of increasing the speed of rotation of the durability of the axles produced according to the manufacturing procedure used today in mass production.