Survey of interior noise characteristics in various types of trains

The aim of this paper is to determine the effects of the wheel-rail friction, motor and tires on noise characteristics in a train car. The octave-band power levels, A-weighted equivalent continuous sound pressure level and parameters extracted from interaural cross-correlation/autocorrelation functions were analyzed to evaluate the noise inside running train cars quantitatively and qualitatively. The three types of noise caused by wheel-rail interaction are rolling, impact, and curve squeal noises. Impact noises had larger components at lower frequencies (< 1000 Hz). Curve squeal noises had larger components at frequencies between 125 and 500 Hz in both underground and surface trains and had dominant frequency components around 250 and 500 Hz with stronger pitch in underground trains. High-speed trains had low-frequency centroids and high binaural coherence compared with normal-speed trains.