The paper presents experimental research carried out to determine the possible actions to reduce the noise generated by trams in a highly urbanised area. A few design strategies affecting tram ride quality have been presented – especially in the aspect of the acoustic phenomena. Main sources of the noise in trams were characterised. The paper includes selected results of comprehensive studies of tram noise in the pass-by test based on the authors’ research methodology. The tests were carried out on various types of trams to recognise the acoustic phenomena characteristic for the rolling stock in a selected tram system. The results of the measurements were analysed both in the field of amplitudes based on noise maps and in respect to frequencies based on noise spectra. The results indicated the rolling noise as important issue demanding taking some actions in order to reduce its level. In this area, elements for the application of individual attenuation solutions, i.e. at the source and during propagation, were presented. The results of the measurements were used as input data to the assumptions of the noise attenuation passive system, which was the final outcome of the study. Dedicated external dampers were used in the case of wheel and rail pairs, where the dominant power of the noise is emitted. The acoustic properties of the bogie area and the bogie side covers were redeveloped to hamper the noise propagation, which is a novel application. The presented results indicate measurable benefits from the applied solutions on the tram noise reduction.

In Poland, the economic use of methane from coal seams has been recognized as one of the objectives of the „Energy Policy of Poland until 2030“. In Poland at the Upper Silesian Coal Basin, reconnaissance operations were initiated to collect methane from coal seams using drilling wells and hydraulic fracturing operations.

During these operations, noise emission can have a significant impact on the environment. In order to limit the negative impact of noise, well pads are usually located in undeveloped areas. However, in the European Union, the majority of hard coal deposits from which methane can be extracted are located in areas with a high population density.

This article presents the results of noise measurements carried out during hydraulic fracturing operations of coal seams and the results of calculations of the equivalent sound level during the daytime. Based on the analysis of noise emission, some recommendations are given regarding the location of planned new well pads in highly urbanized areas in order to meet the applicable standards of noise protection.