Performance Investigation on AA-LRT Level cross Signaling System
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Date
2016-06
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Addis Ababa University
Abstract
Level crossings have been identified as a particular weak point in road and railway infrastructure. Installing efficient and reliable level crossing signaling system ensures the safe operation of the railway network. As most of its subsystem and components are working in open atmospheres, its operations are sometimes very difficult to monitor. Their reliability and maintainability directly affect the capacity and availability of the railway network in terms of both infrastructure and trains operation. Ensuring the safety of both those attempting to cross and the individuals on-board is a primary concern for all AA-LRT operators. In this paper, first from the current AA-LRT railway level crossing signaling system installation and configuration, feared event model is developed (Collision between train and vehicle) by a Fault Tree. Second perform in-depth analyses of the reliability, availability and maintenance of AA-LRT railway level cross signaling system with initial design failure and repair rate data used to estimate the reliability, availability and maintenance for each subsystem. The system is classified in different subsystems in series like barrier, axle counter, rail signal, LC controller and interlocking (CBI). Mathematical model of these subsystems have been developed using Markov process. Then reliability and maintainability of every sub systems are evaluated and graph is plotted for different time intervals to investigate their performance. Moreover, maintenance intervals at different reliability values and steady state reliability of different subsystems are estimated and modeled. Third, study methodologies selected which are quantitative and analytical data analysis methods are evaluated and graph is plotted for different time intervals. The analysis from this thesis shows that reliability of barrier, rail Signal, LC controller, CBI and axle counter are 0.66, 0.98, 0.99, 0.96 and 0.96 respectively after 5000 hours, the reliability of the entire level crossing after 5000 hour of operation is 60.00 % and maintainability of Barrier, Axle counter, LC controller, rail signal and CBI after one hour are 0.865, .899, 0.926, 0.939, and 0.909 respectively according to the design data.
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Keywords
Level Crossing, availability, reliability, maintainability, safety policy, Markov process, feared event, fault tree