Risk assessment of assets based on FMMA and enhanced FMEA: A use case applied on railway infrastructure

The efficient and reliable functioning of today’s society depends on the smooth operation of many complex systems. Among many other systems, transportation infrastructures play an integral role in providing today’s so “self-evident” service level. These systems are unreliable in the sense that they degrade with time and usage to a point where they fail or are no longer capable of delivering the required standard. Different malfunctions and breakdowns can significantly impact the performance of a complex system. Hence, to gain an understanding of the effect of individual components and associated failure mechanisms on a system is a crucial step towards improvement of its overall performance. This paper presents an approach based on a combination of FMMA and a modified FMEA to systematically analyse the maintenance and failure mechanisms of the individual system components. A classic FMEA risk assessment approach has been modified to address the known points of criticism as found in the literature. Thereby, not only reliability, but also impact on safety, economic factors, or even the public image of a corporate company may be considered. In order to describe the criticality of the system elements and their failure modes, various parameters for evaluation were introduced. This builds the basis to improve maintenance strategies for each of the individual damage mechanisms to ensure the efficient operation of complex systems.