Noise sources and control inside a high-speed train car
Noise in the car comes from four kinds of source: wheel–rail contact, aerodynamics, onboard equipment and passenger activity. Knowing which is which decides whether to control at the source or to block transmission.
Four kinds of source
Vibration from wheel–rail contact travels through the car structure and becomes the noise passengers hear; as speed rises, aerodynamic noise from the interaction of vehicle and air grows, with turbulent zones at the nose and sides; air conditioning and electrical equipment make noise when running; and passengers' talk, phone ringtones and luggage friction also affect comfort.
Control at the source
Optimise wheel–rail materials and design to reduce vibration; improve the vehicle shape and shrink turbulent zones to cut aerodynamic noise; optimise equipment design and operating state to lower equipment noise.
Blocking transmission
Use sound-insulating materials in the vehicle design, especially damping materials on the floor and walls, to reduce transmission of wheel–rail and aerodynamic noise; optimise the car layout, for example with insulated and quiet zones, to ease the effect of passenger noise.