The vibro-acoustic characterization of a light rail vehicle is presented. Object of the study is "The Sirio" platform, ANSALDOBREDA's proposal for city transport on rails. The approach followed in the present work can be distinguished in 3 different fields of analysis: the vibro-acoustic characterization of on board equipments made on vehicle, the vibro-acoustic characterization of the vehicle while running, the vibro-acoustic-analysis in laboratory on alone components such as traction motor and air conditioning equipment. During the acquisition tests, accelerometers and microphones were arranged along the vehicle, both inside and outside, close to on board equipments and traction different sensors setup configurations have been used and for each one it has been recorded the frequency response contribution of each sensor. Data's analysis is addressed to evaluate the role of each equipment and the role of wheel-rail noise source on the noise and vibration overall level of the vehicle.