ABSTRACT
Railway systems design activities are carried out to deliver a system which complies with the applicable requirements. In this framework, reliability, maintainability, and availability (RAM) analyses are performed to influence design choices and increase the confidence that the system will perform as predicted. Despite these efforts to identify and quantify the credible failure modes and their potential effects on the system and mission, the in-field experience has to verify the completeness and accuracy of design phase studies up to system acceptance. This chapter is structured on different levels to present the methods used for successful RAM demonstration in the field. Primarily, the principles of data collection failure reporting, analysis, and corrective action system and processing are presented. The parameters of the interest of infrastructure and trains, data collection means, failure data, and root cause assessment are investigated. Subsequently, the methods used to demonstrate compliance with the RAM requirements and the underlying theory are illustrated.
Main reliability demonstration techniques are explained, and a warning is expressed against apparently simple alternative methods, which are, in fact, incorrect and may lead to excessive risks. Methods for availability demonstration tests are discussed and illustrated, and practical examples are proposed. The maintainability demonstration topic is addressed as well, including sample sizing and selection criteria.
