Railway vibration emission model based on a multi-contact source-receiver mobility approach

Railway ground-borne vibration emission is an ongoing issue, which shows a need for vibration emission characterization and prediction where the approach used should ensure transferability from one site to another. This transfer is often calculated using heavy frequency-based (narrow band) numerical models. This paper suggests a quicker approach, where the rolling stock/track/ground system is considered as a source-receiver mechanical system and the three parts of the system represented by their mechanical mobilities. In such a mobility approach, the passing train acts as primary vibration source (represented by a line of uncorrelated forces applied to the track), and the track acts as a vibration transfer system between passing train and ground. The couplings between passing train and track and between track and ground are both represented by a multi-contact line with the same spatial resolution. The output quantity is the line of uncorrelated contact forces (contact force density) applied to ground and the quantity used to evaluate the railway vibration emission is the vibration power transmitted to ground. An application of this mobility approach to IC trains rolling on ballasted track laid on typified homogeneous soils (soft, medium and stiff) is presented.