Modelling of Train Noise at Underground Metro Stations: A Case Study (Cairo Metro)

Abstract

Metro has become one of the most used means of public transit due to its advantages such as high capacity, safety, fast speed, and comfort. Despite its benefits, workers and passengers ride the metro daily are continuously exposed to a high level of noise. Noise exposure has been related to various health-related issues. This research presents an evaluation of the acoustic environment inside operating metro units and at the stations' platform then studies factors affecting the noise levels. By carrying out a noise assessment, one can identify the risks your workers and commuters are being exposed to and also allows people to raise awareness of railway trains' safety, health, and environmental issues. The noise levels inside metro units are considered significant problems that make passengers suffer from severe damage to their health, especially those who use the metro periodically. This research aims to define the factors affecting the noise levels inside metro units and develops models to estimate the noise in the metro unit while moving between stations. Greater Cairo Metro (GCM) Line 1 has been selected as a case study. A sound level meter is used to measure the equivalent sound level in dBA and to evaluate the noise inside metro units. The results indicate that the noise levels are unacceptable compared with the international noise exposure standards. The highest measured noise level inside metro units is 91.2 dBA. These unacceptable noise levels led to more investigation of factors that may affect noise levels inside metro units. Other data have been collected, such as the speed of the train and the track alignment details. The results showed that the noise increases with the increase of the train speed until the speed reaches a specific value, then it decreases depending on the maintenance status and the train type. In addition, the noise levels through curved underground tracks are higher than the levels along straight surface tracks by 18 dBA.