Adverse weather conditions can lead to the deterioration of a train’s aerodynamic characteristics, thereby compromising operational safety. As a common type of severe weather, heavy rainfall not only worsens the aerodynamic performance of trains but also exerts impact forces on them, significantly affecting operational safety. Investigating the wind and rain loads acting on trains under heavy rainfall conditions provides essential data support for ensuring operational safety. In this study, an airflow field computational model is established using the Euler method and validates through wind tunnel experiments. A rain field computational model is established using the Lagrangian method and is validated by the mass of raindrops impacting the train surface. The airflow field and rain field are coupled using the momentum exchange method and are validated through rainfall experiments. On this basis, the relationship among raindrop size, raindrop velocity, and raindrop impact force is investigated via raindrop impact tests, leading to the development of a rain load calculation model. The wind and rain loads on the train under heavy rainfall conditions are subsequently analyzed. Furthermore, nonlinear regression is applied to rain load data at different train speeds, resulting in empirical formulas for rain load estimation. The computational results indicate that, with constant train speed and crosswind speed, the aerodynamic drag and lift force on the head train, middle train, and tail train increase with rainfall intensity. The aerodynamic lateral force on the head train and middle train also increases with rainfall intensity, while the negative aerodynamic lateral force on the tail train decreases and the positive aerodynamic lateral force increases with rainfall intensity. Under the conditions of a train speed of 350 km/h, crosswind speed of 30 m/s, and rainfall intensity of 500 mm/h, the ratios of longitudinal rain load to aerodynamic drag for the head train is 0.97. The ratios of lateral rain load to aerodynamic lateral force is 0.0246. The ratios of vertical rain load to aerodynamic lift force is -0.00318.
Sheng et al. (Sat,) studied this question.