Evaluation of primary suspension for heavy haul wagon dynamics

The classical design of the three-piece bogie for heavy haul wagons does not have a primary suspension and has proved its concept by its performance during operational service. It has also been demonstrated that the inclusion of primary suspension in the wagon design can improve both ride quality and lateral stability. Such an improvement has recently been implemented on heavy haul wagons. However, a study evaluating the pros and cons for such a design are worth revisiting. This study provides an advanced multibody simulation of a heavy wagon (120 tonnes gross) with three primary suspension design variants operating under different wheel-rail friction management and track conditions. The investigation involves varying the input parameters in order to observe the response of vehicle/track systems. Particular attention is given to the resulting P2 forces which have the potential to damage wagon and track components. The study takes into consideration all stages of the operation of a heavy haul train, utilizing results delivered from longitudinal train simulations performed on a typical heavy haul route and information provided on the lateral coupler forces acting on the wagon. Recommendations on the improvement of wagon designs are provided with respect to primary suspension components and operational conditions will be included for the chosen heavy haul study cases.