Performance of Urban Rail Transit System: Vibration and Noise Study

Abstract

Vibration and noise are two major factors in the performance assessment of rail transit systems, particularly in an urban environment where elevated systems are used. A program of field measurements was conducted in Singapore on an elevated section of straight tracks to monitor the rail vibrations and noise generated during the passage of trains. Field measurements included impact hammer tests to determine the driving point impedances of the train wheel and track support system. These tests are relatively easy to perform, requiring only an inverted wheel-set-and-bogie assembly at the workshop and the tracks at the test yard. An analytical train model was developed to predict the level of rolling noise at the wayside of the tracks for comparison with measured levels. The analytical predictions from the model were found to be in good agreement with field measurements. A hybrid approach involving a finite-element model of the track support system and impact hammer test results was also presented to determine the effect of using softer rails pads.