This machine can combine 900 ton tyre trolley to work for double-line high speed Railway Bridge with box beams in the length of 20m, 24m and 32m. 1)Working environment and condition ·Launching concrete box beam with same length span or different length span, with ballast or without ballast. ·Different height of the concrete box beam in one bridge · Surmountable slope 3 % · Min. radius of the bridge 1400m ·Wind speed: 72km/h with load, 144km/h without load. 2)Main technical characteristics · When the launching gantry finishes placing concrete beams and the under bridge tries to launch forward,the whole machine is driven by the chain system of the small trolley under the launching leg. That can ensure a stable movement, and will never create additional force movement to the gantry. · When the location of machine assembly is close to the launching jobsite, the launching gantry can move to the abutment itself and can also place itself on the pier to be ready to erect concrete box beams. · After finishing erecting the concrete beam of one bridge, the launching gantry can move forward by itself on the deck or go through the existing deck or steel bridge. · With the help of special transporting frame, the launching gantry can be moved on the railway basement or deck by tyre trolley. ·When it is necessary to go through certain areas with height limits or some narrow areas such as tunnels, the machine can be partly disassembled to reduce its section dimension. Then with the help of transporting the frame, the launching gantry can pass the limited area.