Effect of rail irregularity wavelength on lateral runningcomfort of speed-raised train

In order to improve the riding comfort of speed-raised train, the effect of rail irregularity wavelength on the running comfort of speed-raised train was analyzed by means of experimental data and based on vehicle-track coupling dynamics, the irregularities with different wavelengthes were calculated from rail power spectral density. Analysis result shows that if the wavelength range is from 1 to 20 m, the main frequency of carbody vibration is in the scope from 2.20 to 4.00 Hz and the riding index of speed-raised train is excellent at a speed of 150 km·h-1; if the wavelength scope is from 20 to 30 m, the main frequency will decrease to the level of 1.50 Hz, which is accordable to the sensitive frequency of body, the riding comfort will reduce greatly, and the riding index will increase by more than 20%; the long wavelength is more than 30 m, the riding comfort changes little, and the riding index is the same as that of medium wave range from 1 to 20 m. Obviously, in order to improve riding comfort of speed-raised train, much measure should be taken to control the wavelength scope from 20 to 30 m on existing lines.