The stochastic characteristics of wideband-wavelength track irregularity on Chinese HSRs and its application to dynamic wheel–rail interaction

Track irregularities are the major excitations which lead to unfavourable wheel–rail dynamic interaction. In this work, the stochastic characteristics of longitudinal level irregularity on Chinese ballastless high-speed railway (HSR) are analysed based on a series of large-scale measurement campaigns on various arterial lines in Chinese HSR network. The power spectrum density (PSD) of longitudinal level irregularities of various track types is obtained, covering short and middle-to-long wavelength range, as well as the periodical irregularities caused by characteristic lengths of track components. An irregularity spectrum is proposed to represent the stochastic characteristics of the longitudinal level irregularities. Unlike existing irregularity spectra which represent the short and middle-to-long wavelength irregularities separately, the proposed spectrum covers a wide range of wavelength from 0.002 m to 100 m. A vehicle–track model which couples flexible wheelsets and the ballastless track is employed to demonstrate the suitability of the spectrum. It is shown that the proposed spectrum is more suitable than the latter to represent Vehicle–Track Interaction (VTI) on Chinese HSRs. The fitted short-wave spectrum and the proposed wideband wavelength spectrum therefore provide more appropriate representatives of track irregularities for accurate modelling of VTI on Chinese HSRs and railway lines which adopt similar technologies.