Internal noise reduction in railway carriages: A case study in China

To enhance the travel environment of passengers, various damping materials are tested on new Chinese railway carriages; namely bitumen based, butyl rubber and water based materials. Two sets of experiments are carried out indicating that internal noise is spatially non-homogeneous in the whole carriage and dominated by low-frequency contents below 250 Hz. The faster the speeds, the greater the noise reduction in a carriage in terms of the A-weighted sound pressure level. At 150 km/h, the bitumen-based damping sheet along with water-based coating reduces internal noise by 5.7–8.6 dBA, and butyl rubber damping by 3.1–6.2 dBA with the former performing better in the major frequency range of 100–160 Hz.