Novel multi-scale characterisation of new and used field rail grinding stones

Effective rail grinding is essential to remove surface defects and limit rail deterioration while producing a post-grinding surface condition that minimises the risk of damage initiation. This study examines the wear behaviour of resin-bonded grinding stones, which directly influence grinding efficiency and key aspects of surface integrity, including roughness and potential white etching layer formation. One new and three field-used stones worn to different levels were analysed using macro- and micro-scale methods. Findings show a rapid transition to a stable worn state, marked by surface tapering, grain pull-out, wear flats, and bond degradation, with topographic variation across the cutting surface suggesting localised grinding behaviour. These findings establish a baseline for understanding field stone wear and provide the surface characterisation needed to replicate such conditions in laboratory testing, enabling future investigation into their effect on rail surface integrity.