The invention belongs to the technical field of rail wagons, and particularly discloses a tilting air cylinder, which solves the problems of difficulty in 
machining, inconvenience of mounting, unsmooth work process, relatively lower air pressure 
bearing capacity in work, a plurality of 
casting defects of castings, and the like of the conventional tilting air cylinder of an automatic dumping vehicle. In the tilting air cylinder, an outer cylinder and a middle cylinder are both formed by assembling and 
welding independently-molded components; an outer cylinder body of the outer cylinder has a tubular structure formed by coiling and 
welding a board; an inner cylinder 
barrel of the middle cylinder also has a tubular structure formed by coiling and 
welding the board; a lug is provided with a gas passage; one end of the gas passage is connected with a main air 
pipe, and the other end of the gas passage is connected with an inlet 
pipe of the outer cylinder body; and the lower end of the inlet 
pipe is communicated with an air inlet at the bottom of the outer cylinder body. The tilting air cylinder has the advantages of reducing the 
rejection rate and the production cost, avoiding the 
casting defects of the original castings, reducing 
dead weight, improving the appearance quality, eliminating own swing and avoiding further faults.