Effect of train heights on aerodynamic performance of high-speed trains under crosswind

• Increasing train height from 3.89 m to 4.19 m raises the side force coefficient by up to 61.54% under a 20 m/s crosswind. • Roll moment coefficients on head, middle, and tail cars increase by 18.11%, 24.78%, and 34.23%, respectively, for the tallest train. • Taller trains intensify wake vortices and expand the back-flow region, increasing turbulent fluctuations and Reynolds stress on the leeward side. • The findings provide critical design references for optimizing train height to ensure stability and safety in crosswind conditions.