Internal noise reduction in railway vehicles by means of rail grinding and rail dampers

Abstract

Interior noise reduction has become an important concern in railway operating environments due to the influence of increased speeds and reduced vehicle weights on energy efficiency. Two types of measures, rail grinding and rail dampers, were proposed to reduce the internal noise within railway metro vehicles on a particular curve section of a Chinese metro line where the internal noise within metro vehicles is so excessive when the train passes that drivers and passengers complain. The dynamic property and track decay rate of the track system were carried out through mechanical shock method first. Then the measurement of rail vibration performance, external noise and internal noise were conducted when the metro train passed through this track section at the required speed. The rail corrugation with a wavelength of 0.06 m is a major cause of the excessive internal noise. After the application of rail grinding, the overall A-weighted sound pressure levels reduced from 85 to 82 dB due to the removal of the rail corrugation and other short-wave irregularities. Moreover, after the further use of rail dampers, the overall A-weighted sound pressure levels within the carriage further decreased from 82 to 74 dB, resulting from the reduction of the wheel/rail external noise transmitted into the vehicle body through leaks in the vehicle body. Therefore, the noise reduction effect of the two presented measures is significant.