Abstract:Abstract : Research purposes : If we can calculate the value of gradient discount of heavy - haul railway tunnel reasonably, construction investment is saved, the length of tunnel is shorten, construction risk and difficulty is reduced. Combined with feature of heavy - haul railway, this paper calculates and analyzes the value of gradient discount of heavy -haul railway tunnel,and compares the value of heavy - haul railway with normal railway. At the same time the feasibility of elimination of gradient discount of tunnel is analyzed from the theoretical calculation and operation,finally suggestion on the value of gradient discount of heavy - haul railway tunnel is proposed. Research conclusions:( 1) The value of gradient discount of heavy - haul railway tunnel is not same as the value in code for design of railway line,and should be calculated on addition air drag parameter in tunnel. (2 ) In order to save investment,the value of gradient discount of heavy - haul railway tunnel can be reduced or eliminated in difficult geographic and geomorphic conditions. (3) The conclusions can provide some references for designing value of gradient discount of heavy - haul railway tunnel.