INTERIOR STRUCTURE-BORNE SOUND CAUSED BY THE SLEEPER-PASSING FREQUENCY

This study deals with the parametric excitation caused by the discrete sleeper support of the rail, the so-called sleeper-passing frequency. If the wheelbase is an integer multiple of the sleeper distance the vibration transmission to the body is believed to be increased. Tests were made on UIC 60 and SJ 50 tracks, with sleeper distance of 65 cm, for six speeds, from 130 to 250 km/h. A X2000 train set with one extra car were used. The extra car, X15-5, has bogies with a 2·7 m wheelbase whereas the ordinary cars have bogies with a 2·9 m wheelbase. The structure-borne sound caused by the sleeper-passing frequency can in some cases be the overall dominating noise source in a coach.