Combining crack-growth, contact geometry, and probabilistic methodology to plan optimised rail grinding

This research was undertaken to assist infrastructure managers (IM) to plan the utilisation of their grinding trains: an expensive resource. It was undertaken to support increasing the competitiveness of rail freight by considering combined improvements in both freight vehicle and track components in a holistic approach including economic assessments. A major cost to freight operators are the access charges that IM charge to cover the costs of track maintenance; these costs (and hence access charges) may be reduced if maintenance requirements can be linked more closely to loads imposed by traffic, enabling optimum grinding schedules to be developed and life cycle costs of rail to be reduced. Infrastructure managers undertake grinding to prevent the growth and/or formation of rolling contact fatigue (RCF) cracks, to remove corrugations from the rail head, and potentially to improve acoustic track quality and hence the sound pollution associated with rail operations. Grinding is the most expensive maintenance operation carried out on railways in the UK; in 2008 it was reported to cost £0.08/kgtkm (2006/07 prices); this was 30% more per kgtkm than plain-line tamping and twice that of changing rail due to defects. It is thus important to apply grinding efficiently and optimum grinding strategies have been the subject of considerable research. This paper focuses on strategies for the removal of RCF cracks, extending the work reported in