Effect of metro rail corrugation on dynamic behaviors of vehicle and track

The characteristics of rail corrugation were measured by using corrugation analysis trolley, the vibration accelerations of vehicle and track components were measured by using acceleration and displacement sensors before and after rail grinding, and the effect of rail corrugation on the vibrations of vehicle and track components was analyzed. Vehicle-track coupling dynamics model was established to analyze the effect of rail corrugation on wheel/rail interaction force and to determine the limit value of rail grinding. Study result shows that the main wavelength of rail corrugation is 30-40 mm and the secondary wavelength is 16 mm. The vibrations of railhead and fastener clip at 650-800 Hz and the vibrations of axle box at 670-800 Hz are in accordance with the passing vibration behaviors of vehicle with wavelength of 30-40 mm. So the short-pitch rail corrugation leads to the strong vibration of metro vehicle and track components, and it is the main cause of fatigue fracture of primary suspension springs and track fastener clips. Rail grinding can effectively solve fatigue fracture problem. Before rail grinding the root mean square values of vibration accelerations of railhead, fastener clip, sleeper and ballast bed are 243.4, 309.3, 17.1 and 2.6 m·s^-2 respectively, and after rail grinding they decrease to 51.5, 8.8, 1.5 and 0.5 m·s^-2 respectively. When the depth of rail corrugation is 0.1 mm, wheel/rail vertical forces are 307 and 109 kN with wavelengths of 35 and 80 mm respectively, and wheel/rail transverse forces are 56 and 25 kN with wavelengths of 35 and 80 mm respectively. So wheel/rail vertical and transverse forces are very sensitive to the wavelength of rail corrugation. When vehicle operation speed is 90-120 km·h^-1, the depth of rail corrugation with wavelength of 35 mm is 0.05-0.08 mm according to the limited criterion of wheel unloading rate, and the depth is 0.03-0.06 mm according to the limited criterion of wheel/rail vertical force. So rail grinding should be carried out when the depth of 30-40 mm short-pitch rail corrugation reaches 0.05 mm.