Vibration Response for class D44 and D39 200 Locomotive Wheelsets due to Dynamic Loads Excitation

Wheelset vibration response of two Transnet locomotive classes i.e. D39 200 and D44 are investigated using the modal analysis method. These two locomotive classes are the only classes used on the Belfast to Steelpoort railway line in the Limpopo Province of South Africa. The class D44 replaced the class D39 200 locomotives over two years ago. Short-pitch rail corrugation exists on rail track curves of the railway line. The axial (lateral) resonance frequencies of wheelsets from both locomotive classes prove to be more, than resonances in any other direction of vibration. This is in good agreement with the previous tests done on a class D39 200 locomotive wheelset. The axle coupling vibration response was measured in the axial direction by exciting one wheel and measuring accelerance of the opposite wheel on the wheelset. Vibration response for the class D44 wheelset shows more lightly damped resonance modes in the axial direction. The characteristics of the axial vibration response being lightly damped with the highest accelerance implies most of the vibration occurs in this direction and may be associated with most rail track damages.