Impact responses of highspeed railway track slabs

Impact loads pose a lot of hazards including causing severe damage to both railcars and rail track components, for example, cracking of slabs or sleepers. The impact loads can be as a result of several factors including flat spots on rail wheels attributed to the train braking, dipped rails, rail squats, corrugation, crossing transfers, etc. The impact loads are often over a short duration but of very high magnitude. For instance, the typical loading duration produced by wheel flats is about 1-10 milliseconds, while the force magnitude can be over 400 kN per rail seat. This paper highlights an investigation into the behaviour of a slab-track subjected to impact loading. A parametric study has been carried out using the finite element analysis software, Strand7, to investigate the behaviour of slab-track under the action of the impact loading conditions. This was done by analysing the ratio of maximum impact moment to maximum static force under varying slab support conditions. The outcome of this study will potentially lead to a better understanding and hence, the design of slab track systems in highspeed railway tracks subjected to the impact loading. Our study revealed that for a slab-track under the action of impact loading, the slab-track is more sensitive to changes in the support stiffness at midspan than at the rail seats and effects of increasing or reducing support stiffness are more significant at these locations.