The intense, high-pitched squeal noise generated by tram and metro vehicles traversing narrow curves irritates passengers as well as inhabitants. This high frequency squeal noise is due to non linear stick slip (creepage) forces between railway wheel and rail. The lateral sticking and slipping causes vibrations in the wheel to increase until a stable amplitude is reached. Damped and resilient wheels are sometimes used to reduce squeal noise. To reduce wheel rail squeal noise with measures at the level of the track, rail lubrication (or flange lubrication) are used.