Train Wheels Eigenmodes on Effects of Vibration and Track Deterioration in the Belfast to Steelpoort Railway Line

Abstract

In South Africa, one of the main lines situated in its Limpopo Province presents symptoms of excessive vehicle-track vibrations. A modal method is adopted to study the difference in dynamic response of corrugated rails resting on the Hytrel/6385 and High Density Polyethylene (HDPE) rail pads. The results for dynamic response of rails on these two types of rail pads are analysed in form of Frequency Response Functions (FRFs). Two positions are considered in obtaining these point FRFs; those are mid-span and on top of sleeper. Resonance modes of significance are excited in a frequency range of 0 – 500Hz on rails resting on both types of rail pads. In view of the entire vibration response window, the FRFs show a more damped vibration response by rail resting on the HDPE than that resting on the Hytrel/6358 rail pad. A Finite Element (FE) modal analysis method is used to investigate vibration mode shapes and corresponding frequencies of the wheelset used by the locomotive operating in the line. In the high frequency range of 350 – 500Hz, the gear-side wheel of a locomotive wheelset proves to be vibrating more erratically than the non-gear side wheel. Clearly pronounced mode shape excited at a frequency of 350Hz and higher are presented.