BS EN 50126-1:1999

1.1 This European Standard:

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

• defines a process, based on the system lifecycle 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.

1.2 This European 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 lifecycle of an application;

• for use by Railway Authorities and the railway support industry.

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