Online evaluation of railway axle bearing faults using acoustic emission and vibration Analysis

Rail transport is environmentally friendly and ensures efficient and cost-effective mobility throughout the UK. Train wheelsets consist of three main components, the wheels, the axle and the bearings. A large proportion of all equipment related accidents in the rail industry is due to failed axle bearings, wheels and axles. The continuous increase in train operating speeds means that failure of an axle bearing can lead to very serious derailments, causing loss of life, injuries, severe disruption in the operation of the network, damage to the tracks, unnecessary costs, and loss of confidence in rail transport by the general public. In order to ensure passenger safety various manual inspection methodologies are employed to evaluate the condition of train wheelsets during maintenance intervals. However, since wheelset defects can develop in-service and evolve very rapidly the rail industry has invested heavily in the online monitoring of wheelsets to minimise the likelihood of a catastrophic derailment. In this paper we present the results of acoustic emission and vibration analysis measurements carried on actual freight wagons with artificially damaged axle bearings in Long Marston, UK. It is evident that acoustic emission has the capability of detecting faulty axle bearings at various stages of evolution and well before they cause final failure of the bearing.