Analysis of the railway freight car axle fracture

Railway axles are vital parts of passenger or freight railway car. Their failure may result in potentially disastrous consequences with possible human victims. Accordingly, railway axles are designed to be highly reliable, while the maintenance system requires periodically regular non-destructive inspection. However, due to complex exploitation conditions, complex stress state and multiple stress concentration, railway axles could experience fatigue failures. This study presents an attempt to clarify the causes of an axle fracture of the railway freight car for coal transport. Detailed analyses were conducted on the axle mechanical properties. Novel methodology for calculation of the plane strain fracture toughness KIc based on the measured values of the yield strength and impact energy from data of samples with U grove, is estimated. Failure analysis of fractured axle was performed. Macro and microstructure of the axle material is included in analysis. Performed analysis has shown that the axle failure was caused by inadequate maintenance and insufficient properties of the axle material in the railway axle critical cross-sections.