Within the development of a Korean Tilting train including new composite materials, EPFL is contributing to its new design by providing in a consistent way the manufacturing costs assessment and its related environmental impacts. Such environmental expertise is issued from Life Cycle Assessment methods with an innovative Impact Assessment methodology. The Korean Titling Train (*) is one of the first applications of composite materials to structural pieces of a train. This Life Cycle Assessment study is comparing the potential environmental impacts of 1 car-body of a regional train over 25 years made in composite (Carbon fibers) versus the conventional current alternatives based on steel or aluminium. Preliminary results allow to identify major processes determining the life cycle impacts of this one car-body and allow to investigate the advantages of introducing composite in trains. (*) Project undertaken for the KRRI (Korean Railroad Research Institute)