Lateral impact derailment mechanisms, simulation and analysis

• Lateral impact on trains running at steady state velocity is modelled.
• Heavy road truck of mass from 5 T to 120 T running at 10–70km/h is considered.
• Assumed crush zone characteristics of the road vehicle validated using Maxwell model.
• Lateral impact derailment mechanism outlined from simulation results.
• Safe zone boundary for trains impacted by trucks of varied mass and velocity defined.

Lateral collisions between heavy road vehicles and passenger trains at level crossings and the associated derailments are serious safety issues. This paper presents a detailed investigation of the dynamic responses and derailment mechanisms of trains under lateral impact using a multi-body dynamics simulation method. Formulation of a three-dimensional dynamic model of a passenger train running on a ballasted track subject to lateral impact caused by a road truck is presented. This model is shown to predict derailment due to wheel climb and car body overturning mechanisms through numerical examples. Sensitivities of the truck speed and mass, wheel/rail friction and the train suspension to the lateral stability and derailment of the train are reported. It is shown that improvements to the design of train suspensions, including secondary and inter-vehicle lateral dampers have higher potential to mitigate the severity of the collision-induced derailments.