A theoretical model for ground vibration from trains generated by vertical track irregularities

Abstract

A model is developed for predicting ground vibrations due to vertical track irregularities. This model incorporates vehicles, a track and a layered ground, and uses the moving axle loads and the vertical rail irregularities as its inputs. Outputs include the dynamic wheel–rail forces and the displacement power spectra of the track and the ground surface. Results from this model are presented for a single-axle vehicle model and a British Mark 3 passenger coach running on different tracks (a ‘lighter ballasted track’, a ‘heavier ballasted track’ and a slab track) at different speeds (25, 60 and 83 m/s). Based on these results, the effects of track structure, vehicle speed and frequency range on the observed vibration levels are identified. The different roles of the moving axle loads and the roughness-induced dynamic loads are indicated, at different frequencies and for train speeds below and above the lowest ground wave speed