Evaluation of wheel dampers on an intercity train

Abstract

Pass-by noise from high-speed trains is one important area that has to be handled in all new train projects. For the new line between Oslo and the Gardemoen Airport which opened in 1998, very stringent requirements were set out regarding external noise. To reach the target it was decided that the train should be equipped with wheel dampers. Two different types of wheel dampers were used on the train; a ring damper was mounted on the wheels of the driven bogies, whilst plate dampers divided into tuned absorber fins were mounted on the wheels of the trailer bogies. During the type testing of the Airport Express Train, additional measurements were performed in order to evaluate the acoustic effect of the plate wheel dampers. Two test series were performed with the same train set; first with the train in standard configuration and secondly with the wheel dampers removed from the second and third bogie. The external noise was measured at 5 and 25 m distance from the centre of the track at speeds ranging from 80 to 200 km/h. The third-octave filtered time histories were analyzed to calculate the effect of the wheel dampers. As expected, there was a significant reduction of 4–6 dB at frequencies above 2000 Hz, but there was also a reduction of 2 dB for frequencies as low as 800 Hz. This reduction was also found in the parts of the time histories when the rail should be dominating. This implies that the wheel dampers also reduce the rail noise. The total rolling noise reduction for the trailer bogie was 3 dB at 200 km/h and 1 dB at 80 km/h. From comparison with TWINS-calculated sound power levels it was estimated that the wheel noise would be reduced by 5 dB and the rail noise would be reduced by 1 dB at 200 km/h.