Evaluation of primary suspension benefits for heavy haul wagons

The classical design of the three-piece bogie for heavy haul wagons does not have a primary suspension. The low frequency response of the wheel and rail under the short wave track irregularity has a more obvious effect on the wagon during operational service. Rubber pad has been applied in some heavy haul three piece bogie wagons as a primary suspension to reduce the influence of wheel rail interaction on the dynamic performance of wagons. This paper focuses on evaluating the pros and cons for such a design. This study provides an advanced multibody simulation of a heavy wagon (30 tonnes per axle load) with four 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 results show that rubber pads can effectively reduce the wear index and P2 force of wagon wheels under the condition of dry wheel and rail contact, but will increase the wear index and P2 force of the wagon wheels under the condition of wet wheel and rail contact. The impact of rubber pad on the derailment factor is not obvious. 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. © 2018, Department of Journal of the China Railway Society. All right reserved