scope:

This International Standard

- defines RAMS in terms of reliability, availability, maintainability and safety and their interaction;

- defines a process, based on the system life cycle and tasks within it, for managing RAMS;

- enables conflicts between RAMS elements to be controlled and managed effectively;

- defines a systematic process for specifying requirements for RAMS and demonstrating that these requirements are achieved;

- addresses railway specifics;

- does not define RAMS targets, quantities, requirements or solutions for specific railway applications;

- does not specify requirements for ensuring system security;

- does not define rules or processes pertaining to the certification of railway products against the requirements of this standard;

- does not define an approval process by the safety regulatory authority.

This International Standard is applicable

- to the specification and demonstration of RAMS for all railway applications and at all levels of such an application, as appropriate, from complete railway routes to major systems within a railway route, and to individual and combined sub-systems and components within these major systems, including those containing software; in particular

• to new systems,

• to new systems integrated into existing systems in operation prior to the creation of this standard, although it is not generally applicable to other aspects of the existing system,

• to modifications of existing systems in operation prior to the creation of this standard; although it is not generally applicable to other aspects of the existing system;

− at all relevant phases of the life cycle of an application;

− for use by Railway Authorities and railway support industry.

NOTE Guidance on the applicability is given in the requirements of this standard.