Abstract: A rail train is provided in the embodiment of the present disclosure, comprising: a semi-enclosed air duct, the semi-enclosed air duct comprises an air duct top and an air duct side; the air duct top is fixed with an inner top of a rail train body, the air duct side is connected on both sides of the air duct top and extends downward; a large side top, and the the large side top is fixed to the rail train body as a part of a rail train roof, and the large side top is top-sealed at a bottom of the air duct side to form an air passage with the air duct. The rail train solves the technical problem that the roof and the air duct of the rail train are not conducive to overall weight reduction of the rail train.