Effect of shape of concrete sleepers for mitigating of track buckling

Abstract

Track thermal buckling is one of the primary safety issues of continuously welded rail tracks. The lateral track resistance is the main resisting force against track buckling, which is mainly provided through the interaction of sleepers in the ballast material. In this sense, researchers have focused on determining the lateral resistance of various types of sleepers in ballast material through tie push tests; yet the implications of these results on track buckling temperature have not been fully addressed. The aim of this paper is to fulfill this gap by analyzing the performance of three types of concrete sleepers on track buckling temperature: B70, winged and frictional concrete sleepers. A finite element model of the track is developed and updated based on the results of single tie push tests performed on each type of sleeper. The model is then used to estimate the buckling temperature of tangent and curved sections of tracks. In addition, a sensitivity analysis of the parameters involved in track buckling is presented. It is concluded that for a tight curve of radius 100 m, only frictional concrete sleepers can resist track buckling, if a safe temperature of 40 °C is considered for the track. For the same safe temperature, conventional B70 sleepers can only be used in curves with a radius larger than 1200 m.