This paper investigates the noise inside a metro coach running through the most recent tunnel of Cairo.The study focuses on the effects of alignment profiles on the A-weighted noise level.Although the latest line has ...This paper investigates the noise inside a metro coach running through the most recent tunnel of Cairo.The study focuses on the effects of alignment profiles on the A-weighted noise level.Although the latest line has not been studied yet,noise levels inside the old lines attracted the attention of researchers due to their importance as the first mass transit system in Africa.Given that windows are usually kept open,measurements were conducted inside the empty cabin at the end of the train with open windows according to ISO 3381:2005.Results showed that noise emissions inside the running coaches are high and do not follow either international or general national legislation,which presents health hazards for drivers and commuters.Speech intelligibility is required for train radio units and driver consoles for voice communications,which provides a safe working environment for the train crew.The present study reveals that tight curves mainly contribute to high noise.The noise levels are further raised by the reflective surface of the tunnel with a circular cross-section and the unballasted track.Moreover,the noise level is affected by the location of the coach and window conditions(open/close)to some extent.展开更多
基金The authors wish to express their gratitude to Prof.Dr.Tamer Elnady,Eng.Ahmed Abu Sariaa,Eng.Mina Wagih,Dr.Ashraf Abu Kresha,Mr.Michael Weekes,Mr.Malcolm Peart,Eng.Sherok El Gebaly,and the staff of the Egyptian Company for Metro Management.
文摘This paper investigates the noise inside a metro coach running through the most recent tunnel of Cairo.The study focuses on the effects of alignment profiles on the A-weighted noise level.Although the latest line has not been studied yet,noise levels inside the old lines attracted the attention of researchers due to their importance as the first mass transit system in Africa.Given that windows are usually kept open,measurements were conducted inside the empty cabin at the end of the train with open windows according to ISO 3381:2005.Results showed that noise emissions inside the running coaches are high and do not follow either international or general national legislation,which presents health hazards for drivers and commuters.Speech intelligibility is required for train radio units and driver consoles for voice communications,which provides a safe working environment for the train crew.The present study reveals that tight curves mainly contribute to high noise.The noise levels are further raised by the reflective surface of the tunnel with a circular cross-section and the unballasted track.Moreover,the noise level is affected by the location of the coach and window conditions(open/close)to some extent.
