Interfaces, functions and components based failure analysis for railway RAMS assessment

Railway related standards have placed requirements to carry out RAMS tasks in railway projects. RAMS studies require (1) giving answers to the questions associated to the failures in interfaces, functions and components/subsystems, (2) considering system and subsystem level hazards and (3) evaluation of the results in reference to the contracts and standards requirements. Classical methods such as FMEA and Hazard Analysis have limitations in combined handling of these studies. Demonstrating acceptable safety of a technology requires combined, careful and precise handling of the associated information. Failing to do so will lead to over or under estimation of RAMS assessments in projects. Consequently, complications towards safety acceptance by independent bodies and an unplanned increase of RAMS related costs may occur. Objective is to introduce a method that can provide traceable, consistent, transparent, easy to handle and logically structured information related to a system and associated RAMS issues. Ultimate goal is to obtain acceptance towards the RAMS documentation with lowest possible efforts in different project phases by meeting the contractual and standards related RAMS requirements. These can be made possible with the application of a methodology presented herein. The development, maintenance and administration of overall RAM and Safety documentation can be simplified even with improved quality. This has become evident during an example application based on a real system.