SYSML, dedicated to system design, provides graphical models. One of the strengths of these graphical models is that they can be validated by domain experts. However, the semantics of SYSML is given in natural language, which does not allow formal and rigorous reasoning necessary for critical systems for which safety and security are major concerns. Our project aims at modeling and verifying high-level architectures of critical complex systems, in particular railways systems, that must be validated by domain experts. For that, we propose to combine SYSML and the EVENT-B formal method. To master the complexity of such systems, EVENT-B provides refinement and decomposition mechanisms that allow a step-by-step design and make proofs easier to discharge. This paper proposes to extend SYSML with safety relevant EVENT-B mechanisms that enable an automatic translation from SYSML diagrams to EVENT-B specifications. We focus on diagrams that facilitate high-level architecture design, namely package, block-definition, state-transition and sequence diagrams.