Pass-by noise measurement were performed on each validation platform to establish a reference at the beginning of the project. In the end of the project, noise reductions which are industrially feasible within the project time constraints will be im plemented on the same validation platforms (rolling stock and infrastructure), where the effectively obtained noise reduction will be measured. In the same time, rolling stock noise sources are identified from pass -by measurements using arrays of micropho nes. This source ranking is used to define the priority in the development of noise reduction solutions in work packages of the subproject E dedicated to working on individual sources( diesel motor, auxiliary systems, traction motors, wheels). Noise reduction solutions concerning the infrastructure are developed in parallel in SP-G1 for light rail and SP -G2 for heavy rail (see figure 1). Characteristics of the noise sources are also used in the global modelling tool developed in SP -B. This program calculat es the level, the spectrum, the signature and also the sound sample of a train or car pass -by that allow a listening in near field (7,5m, 25m). All these outputs will be calculated under real operating conditions, that means acceleration, deceleration (sim ulation when the vehicle is stopped), braking, curve rolling, stop of the ventilation sources, stop of the motor The tool should have a sufficient degree of realism with reasonable calculation times to perform parametric studies to define the most efficie nt combination of noise reduction solutions. Measurement campaigns to characterize a bi -mode multiple unit As mentioned previously three validation platforms have been selected : the paper will now concentrate on the platform near Paris and measurement carried out in France. Three measurement campaigns have been carried out to characterize the BMU from Bombardier called AGC (Automoteur Grande Capacité). The AGC is a recently developed commuter train for operation in almost all the French regions. Its ha s a low floor entrance, a maximal speed of 160 kph and a capacity varying from 160 to 240 passengers, according to the interior arrangement wished by the operator. It represents the state -of-the-art in its class in terms of low noise emission. Today more than a hundred AGC trains are running for regional services and more than 580 units are expected to be delivered before 2010. The AGC introduces a completely new product family of 3 and 4 car units with either, diesel -electric, electric or for the first time so-called bi-modes versions. This means that the train can run in either diesel or electric mode (single or even dual voltage: 1,5kV and 25kV). The AGC bi -mode is basically an electric train equipped with two diesel generators of each 660kW that can provide power for the electric traction motors and auxiliaries. Most equipment is located on the roof of the train except the diesel power pack, which is located near the bogie. - Figure 2 : AGC bimode Pass-by noise measurement The first measurement c ampaign was carried out on the French validation platform, in Maisons-Alfort, 10 km from Paris. The test site corresponds to an acoustic hot spot