Optimization of Wing Rail Lifting Value for Rigid Frog of Speed-Up Turnout

In order to study the influence of the rigid frog structure irregularity on dynamic characteristics of trains passing through the turnout, based on the theory of wheel-rail contact and wheel-rail system dynamics, a frog model of switch and a CRH2 vehicle model under different wing rail lifting design schemes were established in the case of the rigid frog of Chinese No.12 single turnout. On this basis, the influence of wing rail elevation design on the dynamic characteristics, passing speed, and ride stability of trains crossing the turnout were analyzed. Results show that with the wing rail bending outwards the wheel-rail contact area begins to move outwards when the train crosses a switch, resulting in a reduction in the vertical position of the wheelset center of mass. The problem of lowering the vertical position of the wheel’s center of mass can be effectively solved by setting a reasonable wing rail lifting value, to improve the stability of the train crossing the switch and the comfort of passengers. The design of wing rail lifting can effectively improve the dynamic characteristics of the train passing through the turnout in the straight direction, but the effect on lateral crossing is limited. When the heightening value of the wing rail is set as 3 mm, the optimal effect of wing rail lifting is the best. Compared with the design without wing rail heightening, the maximum values of lateral and vertical wheel-rail forces of the first wheelset of the train passing through the turnout with heighted wing rail in the straight direction are reduced by 45.8% and 30.3%, respectively. In addition, the lateral and vertical accelerations of the vehicle body are also reduced by 42.2% and 26.1%, respectively. With the increase of the train running speed, the dynamic response of the wheels and rails at the time of crossing the turnout is gradually intensified, and a reasonable design of the wing rails will help to increase the speed of the train crossing the turnout. The research results can provide some theoretical reference for the structural optimization design of rigid frog for railway lines in China.