Does the sound radiation of ground significantly contribute to the sound emission of railway lines?

Abstract

ABSTRACT The sound radiated by the ground vibration generated by trains has been estimated by calculation in a case study and compared to the total sound measured on-site. A 2.5D ground numerical model, calibrated from on-site vibration measurements, has been used to estimate the ground vibration field, from which the ground-borne sound radiated has been estimated using the Rayleigh Integral Method. According to the calculations, the estimated ground-borne sound radiated is dominant at low frequencies (below 125 Hz) and otherwise rather negligible compared to the sound directly emitted by the train/track system. Moreover, a small parametric study performed using a 2D source (vehicle and tracks) model coupled to the same ground model shows that the ground-borne sound radiated is ground dependent. The ground should be taken into account as a separate sound source when dealing with railway sound and should be added to the other known sources (track and vehicle components).