On the dynamic behavior of a railway bogie on a roller rig

In the analysis of the stability of railway vehicles, the interaction between the track and wheelset governs the dynamic behavior of the vehicle. In this thesis, the dynamics of a standard railcar bogie operating on a roller rig are compared to that of a bogie on a tangent track. The dynamic behavior of a wheelset is first described as a function of the vehicle forward velocity in order to highlight the theoretical differences that arise when the forward motion of the body is simulated using a roller rig. The configuration of the body is described in the global coordinate system using a set of trajectory coordinates in order to examine the effect of the presence of the forward velocity. These coordinates consist of an arc length that is defined by the distance travelled by a body about a curve, two relative translations and three relative angles. The relative translations and relative angles are defined with respect to a trajectory coordinate system that follows the motion of the body on the curve. The forward velocity is the time rate of the distance travelled by a body about the curve. A numerical investigation is then provided in order to compare the vehicle critical speed and the hunting oscillations of a railcar bogie on a tangent track to those of a bogie operating on a roller rig. The analysis presented in this investigation sheds light on the differences in the contact patch, creepages, contact forces and in the dynamic behavior that occurs when roller rig simulations are used.