For railway signalling and urban transport systems, safety cannot be reduced to a simple check carried out at the end of the project. The most critical functions must be defined and analysed right from the earliest design stages.
This is why major players such as the Paris and New York metro operators, as well as SNCF, call on CLEARSY to carry out safety verification activities at the system level: the aim is to formally specify the requirements necessary to achieve the expected safety level and to demonstrate that they are properly reflected in the system specification documents.
When the fundamental safety principles are demonstrated at system level, the project gets off to a solid start. Development, integration and validation can then build on safety properties established from the outset and demonstrate, at every stage, that their implementation complies with these properties.