Reliability, Availability and Maintainability (RAM) engineering has been applied successfully for decades in many industries such as military electronics for aerospace  , nuclear power stations , and oil field services . Several standards applying to train control have also been produced recently, for instance the IEEE recommended practice on Communication Based Train Control (CBTC) testing , the international standard for Reliability Availability Maintainability Safety (RAMS) in railway applications  and the European version . Better Reliability and Availability (RA) involves a larger capital investment cost but results in lower maintenance cost and fewer system impacting delays. RAM engineering is used to define the optimal level of reliability and availability to minimize those two costs.
This paper introduces CBTC technology, including typical architectures of the subsystems which need to be modeled for the RA analysis. Basic RAM definitions and methods which can be applied to any system, including train control equipment, are presented. Then, the application of RA methods on CBTC system is discussed in terms of requirements, analysis, testing and methods to choose spare parts quantity.