Abstract:
Reduction of rolling noise as well as aerodynamic noise still calls for serious attention to controlling Shinkansen noise, even if the speed of the train comes close to 300 Km/h. This paper presents estimation results of wheel/rail noise based on the field tests, in which two comparisons of noises under different wheel conditions were carried out. The first comparison concerns the noise of solid wheels or of resilient wheels, which were adopted, tentatively aiming to lessen the rail vibration. The second concerns the noise of wheels running normally with brake discs or of wheels tentatively without the discs. The effects of using resilient wheels and brake discs on wheel/rail noise are estimated as follows. (1) In-car noise and 25-m point noise can be lowered by 1 to 2 dB when uisng resilient wheels as a result of attenuation by transmission or diffraction at higher frequencies. (2) The structure noise decreasing effect of resilient wheels proves to be at least 3 dB. (3) It is ascertained that the braking system in Shinkansen using brake discs fixed to wheel webs gives an advantage of lowering the sound possibly caused by the wheel vibration.