IEC 62278-2 Ed. 1.0 b:2025

IEC 62278-2:2025 considers the safety-related generic aspects of the RAMS life cycle and defines methods and tools which are independent of the actual technology of the systems and subsystems.

This document provides:

• a) methods for the understanding of the systems approach to safety which is a key concept of IEC 62278;
• b) methods to derive the safety requirements and their safety integrity requirements for the system and to apportion them to the subsystems;
• c) methods to derive the safety integrity levels (SIL) for the safety-related electronic functions;
• d) guidance and methods for the following areas:
  • 1) safety process;
  • 2) safety demonstration and acceptance;
  • 3) organization and independence of roles;
  • 4) risk assessment;
  • 5) specification of safety requirements;
  • 6) apportionment of functional safety requirements;
  • 7) design and implementation;
• e) the user of this document with the methods to assure safety with respect to the system under consideration and its interactions;
• f) 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.

This document does not specify:

• g) RAMS targets, quantities, requirements or solutions for specific railway applications;
• h) rules or processes pertaining to the certification of railway products against the requirements of this document;
• i) an approval process by the safety authority.

This document is applicable:

• j) to the specification and demonstration of RAMS for all railway applications and at all levels of such an application, as appropriate, from complete railway systems to major systems and to individual and combined subsystems and components within these major systems, including those containing software; in particular:
  • 1) to new systems;
  • 2) to new systems integrated into existing systems already accepted, but only to the extent and insofar as the new system with the new functionality is being integrated. It is otherwise not applicable to any unmodified aspects of the existing system;
  • 3) as far as reasonably practicable, to modifications and extensions of existing systems already accepted, but only to the extent and insofar as existing systems are being modified. It is otherwise not applicable to any unmodified aspect of the existing system;
• k) at all relevant phases of the life cycle of an application;
• l) for use by railway duty holders and the railway suppliers.

This document is not applicable to:

• m) any unmodified aspect of the existing system;
• n) existing systems which remain unmodified, including those systems already compliant with IEC 62278:2002.

IEC 62278-2:2025, together with IEC 62278-1, cancels and replaces IEC 62278:2002. This edition constitutes a technical revision.

This edition includes the following significant technical changes with respect to the previous edition:

• a) creation of this new Part 2 providing, for the first time, safety-related guidance and methods that support the safety management process provided in IEC 62278-1:2025.

The IEC 62278 series forms part of the railway sector specific application of IEC 61508. IEC 62278, IEC 62279 and IEC 62425 comprise the railway sector equivalent of the IEC 61508 series so far as railway communication, signalling and processing systems are concerned. When compliance with these documents has been demonstrated, further evaluation of compliance with the IEC 61508 series is not foreseen. A list of all parts in the IEC 62278 series, published under the general title Railway applications - Specification and demonstration of reliability, availability, maintainability and safety (RAMS), can be found on the IEC website.