Failure of Railway Components and Life Expectancy

Abstract

Historical railway failures have accounted exploration of fatigue properties by Wohler test machine. Axel failures originate from fatigue as well as load variation, corrosion, wear of bearings, curve trafficking and shocking systems. Axles transmit weight of the vehicle to wheels, to meet vertical and horizontal loads formed during static and dynamic movement and carry driving moment and braking moment. Loading geometry, surface quality, corrosion effect, material failure, and heterogeneity of microstructure have led to local stress accumulation on components to initiate failure crack. Current trailing wheelset practice for mainline railway vehicles have incorporated improvements, but original design that dates back to origin of railways is still holding on for several reasons. Transmitting torque is generated by traction motor through helical pinion to main gear and through main gear to wheel assembly. Differences in hardness in forged helical pinion shaft are responsible for failure. Failures in springs appear under increasing shear stresses from straight path to curved path, as well as jerks and impact. Bending stresses due to lateral loading initiate failure under stress concentration. Failure of universal joint causes vibrations in its output shaft to harm other components of power transmission mechanisms to reduce life time.