A wagon-track system dynamics model for the simulation of heavy haul railway transportation

A Three-Dimensional Wagon and Track System Dynamics (3D WTSD) model for predicting the lateral and vertical dynamics of the wagon running at constant speed on tangent track is reported in this thesis. The 3D WTSD model has been developed with particular attention to wagons and track used in heavy haul transportation. The wagon subsystem consists of 37 degrees of freedom (DoFs) representing the wagon car body, the bolsters, the secondary suspensions, the sideframes, the primary suspensions, and the wheelsets. The track modeled as a four layer subsystem consists of the rails modeled as discretely supported Timoshenko beam, and the pads, the sleepers, the ballast, the subballast and the subgrade represented by viscoelastic characteristics. The wagon and track subsystem is connected by the wheel-rail interface subsystem in which the normal contact force is determined using a multipoint Hertz static contact theory and the creep forces in the tangential directions and the creep moments about the normal direction are determined using Kalkar's linear creep theory.

The 3D WTSD model has been validated using several field data reported in the literature by various researchers. The potential of the model in predicting vertical and lateral dynamics of both the wagon and the track components and system is demonstrated through a number of examples. The 3D WTSD model has also been used to examine the sensitivity of the characteristics of wagon and track components as well as the operating speed and magnitude and distribution of loading.