scope:

This part 2 of EN 50126 - considers the safety-related generic aspects of the RAMS life-cycle; - defines methods and tools which are independent of the actual technology of the systems and subsystems; - provides: - the user of the standard with the understanding of the system approach to safety which is a key concept of EN 50126; - methods to derive the safety requirements and their safety integrity requirements for the system and to apportion them to the subsystems; - methods to derive the safety integrity levels (SIL) for the safety-related electronic functions. NOTE - This standard does not allow the allocation of safety integrity levels to non-electronic functions. - provides guidance and methods for the following areas: - safety process; - safety demonstration and acceptance; - organisation and independence of roles; - risk assessment; - specification of safety requirements; - apportionment of functional safety requirements; - design and implementation. - provides the user of this standard with the methods to assure safety with respect to the system under consideration and its interactions; - provides guidance about the definition of the system under consideration, including identification of the interfaces and the interactions of this system with its subsystems or other systems, in order to conduct the risk analysis; - does not define: - RAMS targets, quantities, requirements or solutions for specific railway applications; - rules or processes pertaining to the certification of railway products against the requirements of this standard; - an approval process by the safety authority. This part 2 of EN 50126 is applicable to railway applications fields, namely Command, Control and Signalling, Rolling Stock and Fixed Installations, and specifically: - to the specification and demonstration of safety for all railway applications and at all levels of such an application, as appropriate, from complete railway systems to major systems and to ...