Effect of train speed and track geometry on the ride comfort of high-speed railways based on ISO 2631-1

The operational speeds of passenger trains have been increasing and now often exceed 300 km/h. Higher speeds can lead to increased vibration and reduced ride comfort for railway passengers. This study investigates the combined effect of speed and track geometry on vibration discomfort in high-speed trains. Railway vehicle dynamic models with various levels of complexity are used, with the measured geometry of a section of high-speed track as an input. The models have been calibrated with vibration measurements carried out in a train running over this section of track and then applied to predict vibration discomfort at increased speeds. To evaluate the vibration discomfort at speeds up to 400 km/h, information on track geometry should include wavelengths up to at least 150 m. Vertical irregularities have the greatest effect at all speeds but lateral irregularities are also important. Both the vertical and lateral irregularities of high-speed track should be controlled at wavelengths 50-100 m that excite rigid modes of the car body, corresponding to frequencies of typically 1-2 Hz. Additionally, vertical irregularities with wavelengths 5-12 m that excite the fundamental flexible mode of the car body, typically around 10-15 Hz, should also be controlled. The effects of cant, the rates of change of cant, and the radius of vertical curves are also evaluated although they only have a small effect on vibration discomfort