Failure analysis of signaling system of Addis Ababa-Light Rail Transit

No Thumbnail Available



Journal Title

Journal ISSN

Volume Title


Addis Ababa University


Railway signaling system is one of the most important parts of the many which make up the railway system. It is the vital control system which demands the use of reliable and fault tolerant system as it directly related to the safe movement of passenger trains. Ensuring safety in railway signaling systems is considered as significant as a guarantee of the safe and efficient operation of the whole railway. In fact, one of the most important objectives of a safety analysis of the signaling system is to maintain a high degree of safety. Therefore, to avoid these problems and provide an optimized signaling, a signaling system design should incorporate additional safety analysis. One of the safety analysis methods from design stage is failure analysis which is used to study the whole dynamic system, point out potential failure modes, failure propagation scheme and used to predict about the system. To this end, this thesis presents the failure analysis of Addis Ababa-Light Rail Transit signaling system by employing model-based failure analysis methods and system fault tree, causes and effects, major failures are investigated. Failure propagation models for the subsystems of AA-LRT signaling system are modeled on Matlab-Simulink, where signaling equipments in a main station are represented. Functional interactions between those equipments are also represented. Hierarchically Performed Hazard Origin and Propagation Studies (HiP-HOPS) is used from the most common model-based safety analysis tools to define each signaling system equipment local failure data and to analyze failure models which are done on Simulink. Fault trees are generated as a result for selected hazards in simulations showing the possible causes of failures.



Failure modes, Failure propagation, Model based failure analysis, HiP-HOPS