Railway-induced ground-borne vibration is an undesirable nuisance affecting residents close to railway lines. Although invariant properties are assumed along the longitudinal direction of the track for most typical problems (high-speed lines, metro lines, etc), this hypothesis is invalid for the case of localized defects (e.g. rail joint or turnout, usually encountered on urban networks). Ground vibrations of this form are the result of the interactions between the railway vehicle and track defects. At low vehicle speed (e.g. light transit vehicles, like trams or metros), the dynamic track deflection dominates the ground wave generation meaning that the quasi-static excitation (moving load effect) can be neglected. It is therefore reasonable to consider a single force acting at the wheel/rail defect contact point as the only source of railway vibration. Based on this consideration, a fast approach is described, which combines the time domain simulation of vertical wheel-defect contact, with track/soil transfer functions in the wavenumber-frequency-domain. The latter is defined using a 2.5D coupled finite element/boundary element (FEM/BEM) model for the track/soil. The effect of defect type and train speed is investigated.
