engleski

The impact of the geometry of rail welds on noise level in urban environments

Noise is one of the main causes of reduced quality of life, especially in urban environments, where noise is constantly present. Complaints from citizens living and working in urban zones near traffic routes with intense road and tram traffic are more and more frequent. A study on the impact of tram traffic, which is one of the greatest generators of increased noise levels in the City of Zagreb (Croatia), is presented in this paper. According to data from the Interna-tional Union of Public Transport, tram traffic is much more intense in Zagreb than in other European cities where trams form the backbone of the municipal public transport system. Since the interaction of the wheel and rail has the highest impact on the noise levels, the impact of the geometry of rail welds as a noise contributing factor was studied. Measurements of noise levels were performed in two phases. The first phase addressed noise measurements for tracks with irregularities at the weld zone. The geometry of the irregularities section was first recorded. The second phase involved measuring noise levels at the same locations, but after the irregularities of the rail running surfaces were re-paired. The measurements took the tram type and travelling speed into account. That way it was possible to analyse the results to determine to what extent tram type and speed influences increased noise levels. This study was con-ducted in cooperation with the Zagreb Streetcar Company, the company in charge of reconstruction and maintenance of the tracks in Zagreb. The study results helped to define the impact of the rails running surface geometry in the weld zone on the increased noise levels, and also to determine permissible tolerances for weld geometry on tram tracks in Zagreb.

urban zones; tram traffic; noise level; rail weld; rail running surface

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