Simulation of bogie dynamics under heavy braking

The importance of including the events of braking / traction to the simulation of wagon dynamics is increasingly recognised due to damages caused to running surfaces by these events. To realistically include these events, explicit definition of wheelset pitch degree of freedom in the formulation of the system equation is necessary. This paper presents such a formulation and demonstrates its effectiveness in predicting wheel skid due to heavy braking when the braking force exceeds the adhesion available at the wheel-rail interface. A model of single wheelset bogie and a bogie model containing two wheelsets within a rigid bogie frame are used as illustrative examples. It is shown that the bogie dynamics is affected differently due to sudden heavy braking either at the leading wheelset alone or at both wheelsets simultaneously.