Case Study of Addis Ababa LRT IATP Signaling Subsystem RAM Analysis

With the growing interest in the railway sector, mainly because of energetic reasons (electrified railway), there is a need to increase the efficiency of the railway lines. One way to optimize this sector, signaling system plays an important role for safe running of trains. Railway signaling systems ensure the safe operation of the railway network, and their reliability and maintainability directly affect the capacity and availability of the railway network, in terms of both infrastructure and trains. As most of its subsystem and components are working in open atmospheres, its operations are sometimes very difficult to monitor. In this context, proper and efficient maintenance activities can be useful to its effective operation. This thesis seeks to study the reliability, availability and maintainability of a signaling system with failure and repair data by Markov modeling. Then reliability and maintainability of every sub systems are evaluated and graph is plotted for different time intervals. Moreover, maintenance intervals at different reliability values are also evaluated. Steady state reliability of different subsystems is also calculated. The model is verified with simulation of Addis Ababa LRT signaling systems with different scenarios. The analysis from this thesis shows that reliability of rail signal and switch machine are the lowest among six subsystems, hence it is required more attention than other subsystems and maintainability of onboard IATP equipment, beacon (balise), LEU, CBI, and rail signal is almost good except onboard IATP, switch machine and CBI which is lowest. So onboard IATP, switch machine and CBI are needs special consideration.