Monitoring vertical wheel-rail contact forces based on freight wagon inverse modelling

The safety and stability of freight train operations are closely related to the wheel-rail contact dynamic forces. To evaluate and monitor the wheel-rail dynamic forces based on the accelerations on the wagon components, a two-dimensional inverse wagon model has been developed. To verify the inverse modelling, a detailed VAMPIRE wagon model has been used for the simulations on two cases of track rail top surface and cross-level irregularities. The simulated accelerations on wagon components are then the inputs into the inverse wagon model. Reasonable agreement has been achieved in the comparison between the predicted and simulated primary and secondary suspension forces and wheel-rail contact forces. The inverse wagon model is finally simplified into a one-dimensional vertical model for potential online applications. The predicted and simulated wheel-rail contact dynamic forces are also compared due to the random track geometry irregularities.