Rolling noise characteristics of a metro train in a tunnel with floating slab track

Concrete slab track is widely used in urban rail systems for its low maintenance needs. Where higher ground vibration isolation is required, floating slab track (FST) is applied. However, tests indicate that FST increases interior noise. This research studies the impact of steel-spring FST on rolling noise, using numerical modelling and field measurement. Finite element models of both track types were validated experimentally, and their frequency responses and decay rates were compared. Sound radiation was analysed using boundary element models. Coupled wheel–rail models with measured roughness were used to predict rolling noise spectra. For comparison, noise measurements were carried out on trailer bogies in a tunnel. The results show that the steel-spring FST produces about 10 dB higher rolling noise than conventional slab track below 250 Hz, mainly due to increased vertical slab vibration. For the normal slab track, tunnel wall radiation contributes to low-frequency noise below 250 Hz.