Squeal noise: Squeal noise is a high-pitched noise due to the friction between the wheel and rail while the tram rounds a curve with small radii.

The tram is often seen as environmental friendly, namely nonpolluting and silent. However, complaints from residents living along the lines prove that it may sometimes lead to annoyance. The most significant complaint is the disturbance from squealing noise. Curve squealing of tramway vehicle is a noise with high acoustic pressure and rather narrow frequency spectra. This noise turns out to be very annoying for the people living in the neighbourhood of the locations wherein this phenomenon occurs.