Aerodynamic forces acting on railway vehicles depend not only on the shapes of the vehicles but also on the types of infrastructures. In this study, the railway vehicle is simplified as a finite-length square cylinder. Large-eddy simulations (LES) of the flow around the finite-length square cylinder, namely, the simplified railway vehicle on a flat ground, embankment, and viaducts simplified as rectangular cylinders, were conducted at 40°, 50°, 60°, and 90° yaw angles. The velocity field around the finite-length square cylinder on flat ground was also measured using particle image velocimetry to validate the LES results. The side force coefficients of the train model on the thick viaducts were large, and the effect of the viaduct on the flow field was thus revealed.
