Positioning method of track irregularities in high-speed turnout area based on multi-resolution analysis

The assessment and evaluation of complex track geometry parameters (TGP) in turnout areas present challenges for track recording cars due to uncertainties in their positioning on short sections. To obtain precise and reliable measured TGP in the turnout area, a multi-resolution technology based on maximal overlap discrete wavelet transform (MODWT) is used to perform multi-layer decomposition of the longitudinal level. By utilizing the zero-phase characteristic of MODWT, the TGP can be determined by aligning the decomposed weld spacings with their corresponding theoretical lengths. The positioning error is assessed through statistical analysis of measured TGP and numerical simulation using a virtual track inspection method. Finally, a 70 m length of TGP, including the entire turnout section, was extracted with a positioning error of no more than 1.5 m.