Reserach On The Influence Of Ballasted And Ballastless Track Fastening-Down Temperature Difference On The Turnouts

Turnout is a kind of equipment which make the train move across lines, and its geometric characteristics and structural features are the weak link of the track structure. In order to meet the needs of train working and economic, the ballastless track is set after the the turnout straight line, while the ballasted track is set after the the turnout curved line. Because of the difference of fastening-down temperature and ballast longitudinal resistance between ballastless track and ballasted track, force and deformation of turnout straight line and curved line will produce asymmetry, which will have some impacts on turnout. In order to ensure the safe use of seamless turnout, we need master the rules of force and deformation of seamless turnouts.This paper built a FEM model of No.12 ballastless welded turnout, calculated the longitudinal temperature force deformation in different fastening down temperatures with proper parameters and analysis the influence factors.The conclusions are:the forces of turnout are asymmetry because the straight line links with the ballastless track while the curved line links with ballasted track. When fastening-down temperature of ballastless track is constant, with the change of difference of fastening-down temperature between ballastless track and ballasted track, temperature force of straight stock rail, straight guide rail and long point rail does not change, while temperature force of curved stock rail, curved guide rail and short point rail change significantly. With the gap of fastening down temperature of ballastless track and ballast track grows wider, the asymmetry is more obvious. When the fastening down temperature of ballastless track is fixed, as the fastening down temperature grows, the heeling deformation difference of direct and curved switch rail and the relative deformation of the wing rail at first traction point of point rail gets bigger. That means the difference of fastening down temperature has a big influence on the symmetry of turnout. The author suggests that the difference of fastening down temperature of turnout discussed in the this paper could be 10℃, at the same time, the longitudinal resistance of fastening and filler should be adjusted to meet the needs of limiting turnout asymmetry deformation.