Objective With the rapid development of high-speed railways, the train running speed increases constantly, but the issue of running noise has become increasingly prominent. It not only affects passenger riding comfort but also disturbs the living environment of residents along the rail transit lines. Therefore, reducing train running noise has become a key research topic. As the train roof is one of the primary sources of train noise, optimizing the design of the roof acoustic hood is of great significance for improving the in-vehicle acoustic environment.

Method First, a detailed analysis of the noise characteristics of high-speed trains is conducted. Then, combined with the acoustic properties of materials, the sound insulation and noise reduction advantages of various material combinations are analyzed. To maximize the isolation and reduction of external noise transmission into the carriage, an optimization research is carried out on the structure and materials of the roof acoustic hood. Based on the traditional sound insulation and absorption forms, two new-type roof acoustic schemes with multi-layer composite structures are proposed by reasonably combining insulation layers and absorption layers.To verify the sound insulation effect of the new-type train roof acoustic hood, noise at different frequencies is tested according to the national standard GB/T 19889.3—2005.

Result & Conclusion  Compared to traditional acoustic hood, the two new-type train roof acoustic hoods both exhibit superior performance in the mid-to-high frequency range, with a notable improvement in sound insulation within the 300~600 Hz noise frequency band. By comparing the two new-type acoustic schemes, it shows one of them has better sound insulation performance while meeting the light weight design requirements.