The effect of train running on elevated bridge of high-seed railway on existing railway subgrade is analysis by means of the establishment of a pier-soil-subgrade model which is proved to be reliable by comparison with in-field test results. First

the stress state of the existing railway at different traffic conditions is simulated while the influence of rail irregularities and soil modulus is discussed; then

the cumulative settlement deformation under traffic loads of trains is predicted. The research results show that running trains on elevated high-speed railway bridge have little effect on the stress state and accumulated deformation of existing railway subgrade. As a result

the distance between piers and the line spacing in existing railway just need to adjust by the clearance diagram requirements. In case of bad rail irregularities and soil modulus decline

the stress increase induced by high-speed trains won’t exceed 0.5 kPa.