Carbody hunting stability has attracted more and more attention due to its great influence on the dynamic performance of a railway vehicle. To fully understand the correlation between the wheel–rail contact relationship and the carbody hunting stability of an electric locomotive, the wheel–rail contact geometry analysis and the multi-body dynamics simulation are carried out in this work. The focus is on the influences of track parameters (including rail profile, rail cant and track gauge) on wheel–rail contact relationships and carbody hunting stability. A group of rail profiles are obtained by interpolating between the standard CHN60 profile and the worn rail profiles. The nominal equivalent conicity, the effective equivalent conicity and the wheel–rail contact bandwidth for a wheelset lateral displacement of ±6 mm are used to evaluate the wheel–rail contact relationship, while the lateral continuous comfort index is used to evaluate the carbody hunting stability. The simulation results show that keeping the rail cant at about 1/40 and reducing the track gauge and the wear depth at the gauge corner of rail can improve the carbody hunting stability of the electric locomotive. Furthermore, the effective equivalent conicity is a good choice to establish the relationship between the wheel–rail contact geometry and the carbody hunting stability.
Short-pitch corrugation is a serious problem on resilient fastened railway track for many metro lines, causing severe noise and vibration that shortens the life of the vehicle and track components. To address this problem, the formation mechanism of this kind of corrugation is investigated in this study. The corrugation characteristics and natural frequency of the resilient fastener track are determined by field investigations. Then, ‘frequency sweeping’ and long-term rail-roughness prediction models are developed to reveal the crucial role of the interactions between two wheelsets in the corrugation formation and to estimate the effects of speed variations and bogie wheelbase on corrugation growth. The spectral analysis results indicate that the spatial frequency spectrum exhibits several peaks at equal intervals due to the short-pitch corrugation of a resilient fastener metro track, which are related to the third-order rail-bending vibration within the bogie wheelbase at about 775 Hz. In addition, large and small speed variations affect the wavelength and depth growth of the corrugation, respectively. The growth of corrugation depth is amplified when the resonance frequency associated with the corrugation formation is an integer-multiple of the wheel-passing frequency. The wheelbase is also an important factor in determining the corrugation wavelength because of its influence on the resonance frequency.
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