Railways and mass transit transportation systems are experiencing a new growth that will have an important social impact in the global transport domain. Therefore new important steps are required to advance the urgent needs, such as interoperability at train and vehicle levels, support for commissioning and maintenance, communication with ground infrastructure and introduction of new services. The ROSIN project aims at the validation of a complete and open platform, which will be the basis for a new generation of vehicles, consisting of an on-board network that interconnects all various on-board systems and subsystems. Taking advantage of a 10 year effort to specify a standard Train Communication Network (TCN), carried out within the International Electrotechnical Commission (IEC) by Technical Committee 9, Working Group 22, the ROSIN project aims to work out a comprehensive solution that closely addresses users requirements and has been validated and demonstrated extensively, using available technology, in a wide range of applications. The project covers all aspects of the on-board networking problems, addressing key areas such as passenger trains, freight trains and mass-transit (metros and trams). Communication and application requirements are considered, including maintenance needs and openness toward ground networks. Internet technologies are used to bring ubiquitous and low cost access to train data.