Performance assessment of railway track under the impact of longitudinal forces during the implementation of maximum traction modes when using electric locomotives with an asynchronous traction drive

Abstract

Strategic task of increasing carrying capacity of railways requires a constant increase in the mass of trains due to the passage of heavy and coupled trains. Development of heavy haul traffic is one of the most significant technological solutions aimed at increasing efficiency of using the infrastructure's capacity. In this case, capabilities of the track infrastructure become decisive. The article presents the results of experimental studies of the performance of a continuous welded track under the influence of longitudinal forces arising from the motion of modern locomotives with an asynchronous traction drive in the modes of maximum traction and electrodynamic braking. It is shown that it is necessary to take these forces into account when calculating continuous welded track for strength and stability. The object of testing was a railway track under the influence of increased longitudinal forces during the motion of the 2EV120 electric locomotive with the implementation of various traction modes and electrodynamic braking. Tests were carried out on three sections of the Test Center's track of the JSC VNIIZhT, the experimental joint was equipped with special strain gauge pads designed to measure longitudinal forces. According to the research results, it can be noted that the longitudinal forces in the rails caused by the implementation of the maximum traction forces and electrodynamic braking can reach up to 25 % of the maximum temperature forces. The real forces of resistance to the longitudinal displacement of rails in the nodes of intermediate fasteners when tightened with the force provided by the standards are about 3-4 kN, which is significantly lower than the standard values of 14-16 kN, and may be a consequence of the wear of the elements of intermediate fasteners and the state of friction surfaces. These phenomena can cause longitudinal displacement of both individual rail lines and the grid as a whole. The development of a set of measures to prevent this phenomenon requires a wide range of studies in real operating conditions, including optimization of traction and braking modes of driving heavy haul trains.