Experimental Study on Curve Squeal Noise with a Running Train

Field tests were conducted at the Railway Technical Research Institute to clarify the mechanism of curve squeal noise. Simultaneous measurements of noise and vibration on the track side and onboard revealed the following results: (1) curve squeal noise is generated at frequencies closely related to the wheel resonance, (2) squeal noise does not necessarily occur on all curves, (3) the intensity of the squeal significantly depends on the conditions of the wheel and rail surfaces, and (4) the vibration of the leading wheel on the inner rail of the curved sections is the dominant noise source. The vibration generated by the roughness of the wheels and rails was estimated based on the measured roughness and its vibration characteristics obtained by hammering tests. The results show that the contribution of the vibrations caused by roughness is quite small near the natural frequency of the wheels, at which the squeal is dominant.