Influence of track gringing process on rail surface and subsurface topology

An important part of track maintenance is rail grinding. To ensure an economically reasonable track life cycle and to extend the time period between repair tasks, grinding processes should not induce damage in tracks, such as cracks and hardness increase. On the other side, high productivity of track grinding, which tends to induce damage, is crucial to reduce repair disruptions and delays. Research work presented in this paper aims at reducing the lack of knowledge concerning interactions between the track grinding parameters, grinding tool specifications and the topology of the track surface as well as damage of the track subsurface. Industrial track grinding processes were tested under laboratory conditions with a variation of wheel peripheral speed and depth of cut. They were evaluated with regard to the achieved surface roughness as well as micro-hardening, induced cracks and residual stresses in the subsurface zone. Furthermore the influence of different external influencing factors such as environmental conditions, on the results of track grinding is analyzed by evaluating the influence of the track initial temperature on the process results. As a result, the main influencing factors on surface quality and subsurface transformation in track grinding were identified and recommendations on eligible track grinding strategies are proposed that can lead to highly productive yet low-damage track repair.