Optimization of crosswind stability for high-speed trains: Aerodynamic analysis of leeward winglet deflection angles

• A leeward winglet deflection angle of 90° optimally reduces the overall overturning moment by 27.6% compared to the baseline high-speed train model. • Enhancing negative surface pressure on the leeward side via passive flow control with winglets improves train resistance to crosswind-induced overturning. • The study analyzes five deflection angles across head, middle, and tail cars, providing a comprehensive assessment of aerodynamic loads and flow field modifications. • The findings offer practical guidance for aerodynamic design and optimization of high-speed trains operating under strong crosswind conditions.