PSD Analysis of Slab Ballastless Track Irregularity of Qinhuangdao-Shenyang Dedicated Passenger Railway Line

The statistic specimen used by this paper is collected by track geometry inspection car from Qinhuangdao-Shenyang dedicated passenger railway line. Based on the stationarity test of the specimen, fast Fourier transform (FFT) method is used to evaluate the spectrum of the whole specimen space. The power spectrum density (PSD) and related functions of track irregularity are obtained by MATLAB program. By the comparative analysis, it is found that slab ballastless track irregularity is better than ballasted track irregularity, especially track vertical profile irregularity and track alignment irregularity. Slab ballastless track irregularity with a wavelength less than 8 meters is very good, and there is no remarkably periodic component. The left and right rail lateral irregularity of slab ballastless track is uniform. The correlation of vertical profile irregularity of left and right rail is strong, and the correlation of alignment irregularity is weak. Based on general average of the specimen of track irregularity, the parameter values of PSD fitting curve for slab ballastless track irregularity are obtained by the nonlinear curve-fitting algorithm in the least-squares sense, which is excellent reference material to study slab ballastless track irregularity PSD.