Numerical investigation of running dynamics of a freight wagon bogie with variable gauge wheels

Abstract

Many innovations have been made on the basis of vehicles, rails and track structure in railway systems, which are of great importance for humanity. One among of a vast, axle groups called bogies are used to increase the performance of tractive and hauling stock to adapt curves on railway tracks. Thanks to bogies, the wheels provide a better positioning to the rails during their movements. The distance between two rails on railway line varies among various countries and regions around the world. The wheels on the vehicles also have to change and adapt to track according to this track gauge if the start and final points of the intended travel are on different gauge stations. Therefore, there is an additional labour and time loss in the track gauge changing situations of vehicles on railway routes passing over two different gauge. Variable gauge bogies are one of the best solutions to minimizing the cost and time of adaptation. This thesis aims to examine the running behaviour of a bogie design with variable gauge wheels using Numerical Multibody Dynamics Analysis. Wheel-rail interactions and many inter-vehicle interactions can be simulated with multibody simulation software platforms. A conventional three-piece bogie and the new design bogie are analyzed and compared in terms of stability, twisted track analysis and bogie yaw resistance according to the specified standards. "Method 1" was applied to the twisted track and the Nadal criteria were examined. The running safety was checked by staying below the limit values in the standard. On-track dynamic tests were performed only for the new design bogie. These dynamic tests were analyzed separately for various combinations of loading and vehicle length conditions using four differend classes of track according to their curve radii. The variable gauge distance bogie was also tested in two separate track gauges of 1435 mm and 1520 mm, as in the previous tests. Some parts of the studied bogie design were modeled in CATIA V5. In addition, wheel profile, rail profile, tracks in three-dimensional space, wheel-rail pairs and contacts are created in SIMPACK environment. Track and vehicle configurations where dynamic tests are carried out are modeled according to the requirements specified in EN 14363 and EN 16235 standards. An important recommendation was made to the design while performing all the tests. When the proposed design for the bogie was modeled exactly, derailment was observed in the wheels inside the curves. The problem has been solved by connecting the two inner axleboxes in the design to limit relative lateral movements to each other. As a result, while the new design exhibits a different character in terms of stability, it succesfully met the criteria examined in this study in terms of running safety of freight wagons.