In order to analyzes the dynamic characteristics of continuously welded rail track on the long steep grade,the paper takes Gui Yang urban rail transit No. 1 line as an example to establish the integrated model of rail-bridge-pier to investigate the changes of the dynamic characteristics of the track structure under the condition of different grades,different train braking loads and different fastening spacing. The results show that the increasing of grade and braking load is negative to the longitudinal str...