The aim of this thesis is to explore the possibility of applications of Friction Stir Welding technology for the junction of the components of fairings for high-speed trains. The ultimate goal is then to realize a fairing design for AS 300 trains. This work was carried out at the Alstom site in Savigliano with the collaboration of the mechanical integration team. The two main problems that arise with the current types of fairing designs used in the company are the non-recyclability of some parts like composites and the necessity to ameliorate the exterior appearance of the train to meet the requests of the clients and aerodynamics.