Vertical directivity of train noise

Abstract

Field measurements on train noise were made at about 6 m from the nearest rail with the intention of determining the vertical directivity of the train noise. Standard wheels are used in the transit system. The track where the measurements were taken is at grade and with no parapet walls. The experimental data showed that the major noise source is from the wheel/rail interaction zone. It was found that the train noise was maximum near the vertical and decreased by about 10 dB in the horizontal direction. This vertical directivity pattern has not been accounted for by various analytical models proposed so far. The study also indicates that a vehicle skirt may be a useful control measure to reduce train noise spreading to nearby highrise buildings. © 1997 Elsevier Science Ltd.