Gantry type welding device used for welding boxcar side wall

The invention discloses a gantry type welding device used for welding a boxcar side wall. The gantry type welding device comprises a gantry welding machine (2) erected on steel rails (1), predeformation profiling models (4) are arranged between the two steel rails (1), support plates (5) parallel to the steel rails (1) are arranged at the two ends of the predeformation profiling models (4) respectively, a row of positioning stoppers (6) are arranged on the support plate (5) at one side, air cylinders (8) are arranged on the predeformation profiling models (4) at the two ends and in the middle, two movable welding guns (3) symmetrically arranged are installed at the two sides of a beam of the gantry welding machine (2), and compressing ejecting cylinders (10) are arranged under the beam of the gantry welding machine (2). The side wall can be limited on a bottom frame of the device, then the gantry welding machine is used for automatically welding reinforcing ribs, the welding process is fast and stable, and the production efficiency is greatly improved.