Laboratory and numerical investigation on the longitudinal resistance of ballasted railway tracks with steel sleepers

Abstract

In this research, we experimentally investigated ballasted railway tracks' longitudinal resistance and stiffness with standard and advanced Y-shaped steel sleepers. We examined the shares of various track components in providing longitudinal resistance by measuring the displacement of the track panel. Moreover, we validated the results via modeling in finite element software. According to the results, the shares of the rail fasteners and the sleepers in the longitudinal resistance can vary based on the flexibility or rigidity of the track-to-sleeper connection. In addition, a comparison between the longitudinal resistance of these panels with wooden and concrete ones indicated that steel sleepers could provide acceptable levels of longitudinal resistance by requiring less ballast due to their unique geometry. Steel sleepers can therefore provide the necessary stability in track sections where we could not utilize other sleepers due to height restrictions. This resistance also depends on the prestressed torque force in the fastener springs. Precisely, higher prestressed-force results in higher resistance and stiffness. Based on the results, we obtained the longitudinal resistance per sleeper in the track panels with standard steel sleepers and Y-shaped sleepers at spring prestressed torque forces of 80 N.m, 60 N.m, and 100 N.m to be about 5.05, 4.55, 7.5, and 11.4 kN/sleeper, respectively. The results of FE models showed a difference of 5.23, 3.55, 2.61, and 2.06 times when applying a vertical load of 300 kN for the longitudinal resistance compared to the condition of no loading.