Scientific paper ID 2753 : 2025/3

The main objective of the report is to compare the noise levels of different vehicles and different routes of the underground railway (metro) of the city of Sofia.

For the purpose of the report, experimental studies were conducted on the vehicles from the rolling stock of Metropolitan EAD of the city of Sofia, model Rusich, which are operated on metro lines 1 and 2. Noise measurements were made from the Slivnitsa metro station to the Business Park metro station and from the Obelya metro station to the Vitosha metro station. The experimental study was carried out under normal operating conditions on 21.05.2025 in the time interval from 10.30 to 15.00, within the daytime part of the day, with different vehicle loads.

The noise was measured in the different traffic modes for a certain section of the underground urban transport network. A large volume of data was obtained from the experimental studies, the results of which are shown in graphical form in this report. A detailed analysis of the results was carried out and the extremes of the noise level values were established.

During the measurement, the occupied transport capacity of the trains was in the range from 20% to 100% of seated passengers and from 0% to 20% of standing passengers. The report does not consider the morning and evening peak hours in order to focus on the technical condition of the trains, the announcement system, the condition of the aggregates for own needs, as well as the technical and structural features of the route (straight sections, curves and switches) and reaching the maximum speed of the metro train.