铁路应用 可靠性、可用性、可维护性和安全性(RAMS)的规范与验证 第2部分：系统安全方法

[中文适用范围]： IEC 62278-2:2025 适用于RAMS（可靠性、可用性、可维护性和安全性）生命周期中的安全相关通用方面，定义了与系统和子系统实际技术无关的方法和工具。本文件内容包括： a) 理解安全系统方法的措施，该方法是IEC 62278中的一个关键概念； b) 导出系统安全要求及其安全完整性要求的方法，并将其分配给子系统； c) 导出与安全相关电子功能的安全完整性等级（SIL）的方法； d) 以下领域的指导和方法： 1) 安全过程； 2) 安全验证与验收； 3) 组织结构和角色的独立性； 4) 风险评估； 5) 安全要求的规格； 6) 功能安全要求的分配； 7) 设计与实施； e) 使用本文件中的方法，确保与所考虑系统及其相互作用相关的安全性； f) 关于所考虑系统定义的指导，包括识别该系统与其子系统或其他系统的接口和相互作用，以便进行风险分析。 本文件未规定： g) 针对特定铁路应用的RAMS目标、数量、要求或解决方案； h) 针对本文件要求的铁路产品认证的相关规则或流程； i) 安全主管机构的批准流程。 本文件适用范围包括： j) 所有铁路应用的RAMS规范和验证，适用于该应用的所有相关层级，从完整的铁路系统到主要系统，再到这些主要系统内的单个和组合的子系统和组件，包括那些包含软件的系统；尤其适用于： 1) 新系统； 2) 集成到已获认可的现有系统中的新系统，但仅限于新系统新增功能的集成部分； 3) 在合理可行的范围内，适用于已获认可的现有系统的修改和扩展，但仅限于现有系统被修改的部分；其他未修改的部分不适用。 k) 应用生命周期的各个相关阶段； l) 由铁路运营方和铁路供应商使用。 本文件不适用于： m) 现有系统的任何未修改部分； n) 未进行任何修改的现有系统，包括已经符合IEC 62278:2002的系统。 IEC 62278-2:2025 与IEC 62278-1一起，取代并废止了IEC 62278:2002。本版本为技术修订版，相较于前一版本有以下重大技术变更： a) 创建新的第2部分，首次提供了支持IEC 62278-1:2025中提供的安全管理过程的安全相关指导和方法。 IEC 62278系列属于IEC 61508在铁路行业中的具体应用。IEC 62278、IEC 62279和IEC 62425在铁路通信、信号和处理系统方面等同于IEC 61508系列。当证明符合这些文档后，不再需要进一步评估对IEC 61508系列的符合性。 IEC 62278系列所有部分的列表，可参见IEC官网，标题为《铁路应用——可靠性、可用性、可维护性和安全性（RAMS）的规范与验证》。 [外文原描述]： 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.