Wrought iron ties

Abstract

Rail corrugation is one of the most serious problems in metro lines, and its formation is affected by several factors. According to the field investigations and research reviews, rail corrugations generally occur on the low rails of sharp curved tracks. Based on the viewpoint of frictional self-excited vibration causing rail corrugation in the present paper, both the field measurement and numerical simulation are performed to study the formation mechanism of rail corrugation found on the rubber-booted short sleeper section of a sharp curved track. In the field measurement, the vibration signals of rails at three different positions are measured when the vehicle runs across the sharp curved track supported by the rubber-booted short sleepers. In the numerical simulation, an elastic vibration model of a leading wheelset-track system on a sharp curved track supported by the rubber-booted short sleepers is established. The dynamic responses and unstable vibration modes are calculated utilizing the transient dynamic analysis together with the complex eigenvalue analysis. The good agreement between the results of the field measurement and numerical simulation further verifies that the saturated creep forces between the leading wheelset and rails can induce the frictional self-excited vibration of the wheelset-track system on a sharp curved track, which is able to cause rail corrugation. It can be found that the vertical vibration acceleration on the rail surface has a significant fluctuation when the wheelset travels through the relevant measuring point, which means that the friction-induced vibration is happening. Meanwhile, the oscillation amplitude of vibration acceleration and normal contact force on the low rail is much larger than that on the high rail. Therefore, the rail corrugation caused by the frictional self-excited vibration mainly occurs on the low rail of sharp curved track. And the wavelength of rail corrugation caused by frictional self-induced vibration is consistent with that measured at the test site in the actual metro line.