Abstract:Abstract : Research purposes : Guchengwan bridge is the key project of the second double track railway from Jining to Baotou. The main bridge adopts a steel truss beam with 132 m span,which is controlled by terrain, structure height, site and so on. The main span is a simply supported steel truss spanning Beijing - Baotou railway with no vertical member, triangular flat chord and integral joint node. It is the largest span in double line ballasted railway simple - supported steel truss bridge when it has been finished. The paper gives some conclusions about structure,bridge deck selection,structure analysis,preventing brittle breaking under low temperature,and construction schemes on spanning the busy main railway. Research conclusions : (1) Adopting longitudinal - transverse beam system and RPC ballast trough plate in bridge deck, not only could lighten deck weight,but also avoid difficulties such as late maintenance and replacement for the integral ballast trough plate. (2)The possibility of using simple supported structure could prevent the waste of using side span. (3) A reasonable plate thickness, design composition,weld distribution,stress control, and all of these methods could solve the problems about brittleness break of steel bridge under low temperate. (4 ) The main bridge employs parallel rotation with no balance weight construction schemes, which reduces the impact of the construction on the existing railway transport greatly. (5 ) The structure design, new bridge deck system and creative construction scheme in this bridge, may give clues on the same bridge s design and construction in the future.