Following the collection of train operators and customers needs that were compiled in the Requirements deliverable D1.1, with respect to the technical objectives defined in the BOSS project technical annex, an analysis of said requirements has been conducted to determine the BOSS system specifications. The objective of this analysis was first to define several scenarios which would be a basis for the studies and demonstration in the project, and second to define precisely the functional BOSS architecture. From the requirements and the discussion with train operators, four main classes of scenario have been identified as prime interest solutions. These scenarios are presented in Section 2, and their analysis in light of the set of requirements extracted from Deliverable D1.1 allowed to obtain the requirement table presented in annex A, with different classes of priorities according both the railway operator interest and the project objectives. Partners are then primarily expected to contribute to the M1 level of priorities, and possibly M2 lower level according to their resources. A high level system architecture is then described in Section 3, where the interaction between the different subsystems as well as a brief description of the tasks carried out by each of those sub-systems are detailed. The possible declination of this global functional architecture into each scenario is also proposed. Section 4 4 consolidates the technical contributions to the project with the presentation of work to be carried out within each work-package and their corresponding tasks, including foreseen possible technical realisation solutions. Section 5 concludes the document with detailing the further steps in the project architecture and system building. RAPPORT DE CONTRAT