Effects of different aerodynamic configurations on crosswind stability of a conventional train

Crosswind stability studies have been multiplied since the 90s due to the increase in speed and the continuous weight reduction of the railway vehicles. At beginning, most of the attention was devoted to high-speed trains but recent studies have shown also conventional trains that runs at considerably lower speeds may also have a high risk of overturning due to crosswind. In this study, a conventional train designed by CAF has been analysed to evaluate the impact that different roof and underbodies have on the aerodynamic performance of the train. In the Wind Tunnel of Politecnico di Milano, a modular scaled model was tested to determine the aerodynamic coefficients of the different train configurations. Moreover, the procedure described in the European Standard EN14067-6 to assess train stability under crosswind was applied to evaluate the Characteristic Wind Curve (CWC) using time-dependent multibody simulations and the ‘Chinese hat’ wind time history for each train composition. Results have shown a significant improvement is obtained for some configurations, especially when the roof is closed covering the roof equipment with an increment of around 4 m/s on characteristic wind speed.