scope:

Part 2 of EN 50126 * considers the safety-related generic aspects of the RAMS life-cycle. The guidance in this part is still applicable in the application of specific standards; * 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 that this standard does not allow the allocation of safety integrity levels to non-electronic functions. * provides guidance and methods for the following areas: - system life-cycles; - systems safety assurance; - risk assessment process; - risk management process; - application of risk acceptance principles and criteria; - safety integrity concept. * provides the user 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; * addresses railway specifics; * does not define: - RAMS targets 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. * does not specify requirements for ensuring system security. This part 2 of EN 50126 is applicable * to all systems under consideration - as regards safety - within the entire railway system and the stakeholders involved; * to the specification and demonstration of safety for all railway appl ...