ABSTRACT
Environmental noise is an issue that has seen increased awareness in recent years. In this chapter, the various sources of noise and vibration are summarised and methods to control them are discussed. The main source of noise from the railway system is rolling noise from the wheel-rail contact. Models for this are described leading to an overview of potential methods to control it. In addition, impact noise due to wheel flats and rail joints and squeal noise in sharp curves are considered. At high speed, aerodynamic noise becomes dominant due to its higher speed dependence. All these sources of noise can be transmitted to the vehicle interior as well as radiated to the wayside; both structure-borne and airborne transmission paths need to be considered. Ground vibration is also produced, which can be experienced as feelable vibration and as low-frequency re-radiated noise. Methods to control ground-borne noise include resilient track forms; feelable vibration is more difficult to control, although it is important to minimise the vehicle unsprung mass. Finally, ride comfort and the influence of the vehicle suspension are discussed.
