Importance of track modeling to the determination of the critical speed of wagons

This paper presents the application of a three-dimensional wagon-track system dynamics (3DWTSD) model to examine the hunting characteristics of wagons containing three-piece bogies running on tangent track. In the 3DWTSD model, two types of track subsystem were considered--one as a layered viscoelastic track subsystem and the other as a 'rigid' track subsystem. Both the critical speed of wagons and the hunting frequency obtained using the viscoelastic track subsystem are smaller than those using 'rigid' track subsystem. The influence of the wheel profiles to the hunting characteristics is also examined. The worn wheel profile was found to incrrease the critical speed of wagons in addition to changing the hunting characteristics.