The cross-industry track stiffness working group has recently published A Guide to Track Stiffness, a railway engineer’s guide to identifying, understanding and repairing trackbed faults in ballasted track. Prepared and edited by Prof William Powrie and Dr Louis Le Pen, it is available from the University of Southampton online store.
Track stiffness has a major influence on the performance of a railway track. It must lie within certain limits, not only to control deflections but also to maintain track geometry and ensure the longevity of track components. A track support that is too soft, or varies too widely over a short distance, may lead to excessive deformation and a rapid loss of geometry. A track support that is too stiff may result in damage to components such as rails and clips.
Problems associated with track stiffness manifest themselves in a variety of ways, for example, by the presence of voids below sleepers (voided or hanging sleepers), the repeated recurrence of track faults after remediation, and rapid rates of track geometry deterioration. The Guide to Track Stiffness is intended to help practising engineers identify and understand faults associated with track stiffness problems, and select appropriate repair and remediation techniques to get the best out of the existing ballasted track network.
The Guide has been written for engineers operating in maintenance, renewal, engineering and research environments. It summarises the theoretical background and methods of measuring track stiffness before giving typical values of stiffness and deflection, and illustrating how to diagnose problems.
Practical implementation is expected to be primarily through three appendices, containing case studies, each describing a problem and a remediation technique; methods for measuring track stiffness; and a diagnostic flowchart.