In the railway field, graphical representations of domain concepts are omnipresent thanks to their ability to share standardized information with common knowledge about several railway mechanisms: track circuits, signalling rules. This paper proposes a domain specific approach for railway systems modeling and validation by combining the Model-Driven Engineering (MDE) paradigm and a formal method. First, an example of a graphical DSL is defined thanks to MDE tools, and then the formal B method is used to define its underlying operational semantics and to guarantee the correctness of the model's behaviour with respect to its safety properties. Our approach is assisted by the Meeduse tool which animates and visualizes execution scenarios of domain models. Starting from a given model designed in the DSL tool, Meeduse asks ProB to animate B operations and gets the reached state by means of B variables valuations. Then, it translates back these valuations to the initial DSL resulting in automatic modifications of the domain model. Our approach allows a more pragmatic domain-centric animation than current visual animation techniques since the resulting DSL tool allows domain experts, who are not necessarily trained in formal methods, to design and validate by themselves the various domain models.