SILENCE

The Silence project focused on the development of noise reduction solutions for rail and road, more particularly for urban situations, applying a global approach, with work packages dealing with noise sources to be evaluated, and work packages on global modelling, noise annoyance and noise mapping.

The general approach of the project was to identify and establish a ranking of the main noise sources, and to develop solutions of reduction for them. In a second step, the impact of these solutions on the total noise level could be evaluated using a global model. For this objective, the VAMPPASS tool, created during the project, delivered usual information like sound pressure level, spectrum and signature, but also sound samples of the pass-by, necessary for annoyance tests.

Prototypes of silent trains and silent tracks have been tested with the tool and some promising solutions have been found and presented all along the day, like actions on the diesel powerpack (encapsulation…), modification of the cooling system, use of wheel dampers for the train, and track dampers for the track. These solutions have been tested by retrofitting existing trains, but some of these solutions could be more efficient being planned since the creation phase of new vehicles. As examples, the following noise reduction can be expected on the total noise level:

• 5 dB(A) by reducing the rolling noise with wheel and rail dampers,

• 8 dB(A) for a DMU at 80 kph, combining the different solutions tested.

The case of depots has also been studied.