Influence of rail roughness characteristics in Hungary on expected noise reduction effect of “quieter routes” in rail freight transport

To reach the ultimate target of climate neutrality by 2050, the European Green Deal calls for a substantial modal shift of freight transported by road to rail and inland waterways. However, rail freight transport causes significant environmental noise pollution, mainly due to rolling noise generated by the interaction between rail and wheel. To mitigate rail freight noise issues, the concept of “quieter routes” was issued by the European Commission. According to this, on railway sections where significant freight traffic occurs during the night, only freight wagons equipped with composite brake blocks shall be operated. Replacing conventional cast-iron brake blocks with composite ones results in reduced wheel roughness, thereby lowering rolling noise. However, the degree of noise reduction is affected by rail roughness, which is also an important factor to rolling noise. Based on the results of an extensive measurement campaign, characteristic rail roughness values in Hungary are higher than those used in the EU common noise calculation method. The impact of this difference on expected noise reduction effect of “quieter routes” was investigated in this article. The results show up to 2 dB lower reduction in noise emission level under Hungarian rail roughness conditions.