This paper presents a specification of the hybrid ERTMS/ETCS level 3 standard in the framework of the case study proposed for ABZ2018. The specification is based on methods and tools, developed in the ANR FORMOSE project, for the modeling and formal verification of critical and complex system requirements. The requirements are specified with SysML/KAOS goal diagrams and are automatically translated into B System specifications, in order to obtain the architecture of the formal specification. Domain properties are specified by ontologies with the SysML/KAOS domain modeling language, based on OWL and PLIB . Their automatic translation completes the structural part of the formal specification. The only part of the specification that must be manually completed is the body of events. The construction is incremental, based on refinement mechanisms that exist within the involved methods. Regarding the case study, the formal specification includes seven refinement levels and all proofs have been discharged under the Rodin platform.