Evaluation of alternative turnout layout designs for an improved dynamic performance of a vehicle-turnout system

Abstract

The turnout is the key equipment for guiding trains to change lines in railway track, which can affect the vehicle running smoothness and limit the train speed drastically. This paper proposes an optimisation method for turnout layout of the diverging route by considering multiple curvatures or curvature changes through the vehicle-turnout dynamics, and the effect of train speed on dynamic response is studied. For the small numbered turnout, increasing the curve radius of a single circular curve type or using a double radii curves type with a larger front radius can effectively reduce the increase in wheel–rail forces and improve train running quality. For the large numbered turnout, the transition curve can be added to the diverging route to form a circular–transition curve or a transition–circular–transition curve type, thereby significantly reducing the dynamic response of the vehicle-turnout system. The wheel–rail dynamic response increases approximately linearly with the train speed in the circular curve of diverging route, but the increase rate decreases significantly with the train speed in the transition curve part, which is more conducive to the increase of the train speed passing through turnouts.