EN 50126:1999 Railway Applications – The Specification and Demonstration Of Reliability, Availability, Maintainability And Safety (RAMS).
Published by CENELEC – European Committee for Electrotechnical Standardisation.
Provides Railway Authorities and the railway support industry with a process that enables the implementation of a consistent approach to the management of RAMS.
Can be applied systematically throughout all phases of the lifecycle of a railway application.
Defines RAMS in terms of reliability, availability, maintainability, and safety and their interaction.
Defines a process 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.
EN 50126 Lifecycle.
Is a sequence of phases, each containing tasks, covering the life of a system from initial concept through to decommissioning and disposal.
The lifecycle provides a structure for planning, managing, controlling, and monitoring aspects of a system, including RAMS.
Phase
Description
Concept
Develop a level of understanding of the system sufficient to enable all subsequent RAMS tasks.
Review previously achieved safety performance
System Definition and Application Conditions
Define the mission profile of the system and its boundaries.
Establish the application conditions influencing the characteristics of the system.
Define the scope of the hazard analysis.
Establish the Safety Plan.
Risk Analysis
Perform System Hazard & Safety Risk Analysis.
Set up Hazard Log.
System Requirements
Specify the overall System Safety requirements.
Establishment of Safety Management
Apportionment of System Requirements
Define the RAMS acceptance criteria for the designated sub-systems and components.
Apportion System Safety targets and requirements to designated sub-systems and components.
Design and Implementation
Create sub-systems and components.
Demonstrate that sub-systems and components conform to RAMS requirements.
Implement a Safety Plan.
Prepare a Generic Safety Case.
Manufacturing
Implement a process that produces RAMS-validated sub-systems and components.
Use Hazard Log.
Installation
Assemble and install the total combination of sub-systems and components.
Initiate system support arrangements.
Establish Installation Programme.
System Validation
Validate that the total combination of sub-systems, components, and external risk reduction measures comply with the RAMS requirements for the system.
Commission the total combination of sub-systems, and components risk reduction measures.
Prepare, and if appropriate accept the Application Specific Safety Case.
System Acceptance
Assess compliance of the total combination of sub-systems and components with the overall RAMS requirements of the complete system.
Accept the system for entry into service.
Assess Application Specific Safety Cases.
Operation and Maintenance
Operate maintain and support the total combination of sub-systems and components such that compliance with system RAMS requirements is maintained.
Performance Monitoring
Maintain confidence in the RAMS performance of the system.
Collect, analyze, evaluate, and use performance and Safety statistics.
Modification and Retrofit
Control system modification and retrofit tasks to maintain system RAMS requirements.
Consider safety implications for modification and retrofit.
Decommissioning an Disposal
Control system decommissioning and disposal tasks.
