The induced airfl w from passing trains,which is recognized as train wind,usually has adverse impacts on people in the surroundings,i.e.,the aerodynamic forces generated by a high-speed train’s wind may act on the human body and endanger the safety of pedestrians or roadside workers.In this paper,an improved delayed detached eddy simulation(IDDES) method is used to study train wind.The effects of the affiliate components and train length on train wind are analyzed.The results indicate that the aff liated components and train length have no effect on train wind in the area in front of the leading nose.In the downstream and wake regions,the longitudinal train wind becomes stronger as the length of the train increases,while the transverse train wind is not affected.The presence of affiliate components strengthens the train wind in the near fiel of the train because of strong fl w solid interactions but has limited effects on train wind in the far field The induced airfl w from passing trains, which is recognized as train wind, usually has adverse impacts on people in the surroundings, ie, the aerodynamic forces generated by a high-speed train’s wind may act on the human body and endanger the safety of pedestrians or roadside workers. This paper, an improved delayed detached eddy simulation (IDDES) method is used to study train wind. These effects of the affiliate components and train length on train wind are are. the results indicate that the affording components and train length have no effect on train wind in the area in front of the leading nose. In the downstream and wake regions, the longitudinal train wind becomes stronger as the length of the train increases, while the transverse train wind is not affected. the presence of affiliate components strengthens the train wind in the near fiel of the train because of strong fl w solid interactions but has limited effects on train wind in the far field