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The University of Southampton
µ-VIS: Multidisciplinary, Multiscale, Microtomographic Volume Imaging

Computed Tomography of rolling contact fatigue damage in rail axle bearings

Ilaria Corni and Nicola Symonds

nCATS, Faculty of Engineering and the Environment, University of Southampton


Rail axle bearings are fundamental components for train safety. On-board real-time vibration condition monitoring offers the opportunity to study the initial degradation stages of rail axle bearings removed from passenger trains. From the analysis of numerous damaged bearings, rolling contact fatigue (RCF) has been identified as the main failure mechanism involved.

Role of Computed Tomography

The micro-CT capabilities at µ-VIS can produce high resolution 3-dimensional data of the internal structure of the material. This capability has been key to fully characterize the RCF damage found within rail axle bearings. The micro-CT data have been employed to generate virtual cross-sections of the damage to identify and characterize the propagation mechanisms of sub-surface cracks before “spalling”. This tool has been key to increase the understanding of the propagation of these failure modes, and the implications for the condition of bearings in service.


The authors would like to acknowledge the EPSRC IAA support and Perpetuum for funding and the Southeastern staff for their assistance during the work.



Image of a part of the damage – the line shows the position where the virtual cross section has been taken.
Image of a part of the damage; like: localisation of virtual section
Virtual cross section showing a sub-surface crack around 7 cm long
Virtual cross section showing a sub-surface crack around 7 cm long
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