Reliability, Availability and Safety Analysis of Addis Ababa Light Rail Transit Interlocking System
| dc.contributor.advisor | Yihenew, Wondie (PhD) | |
| dc.contributor.author | Almaz, Assire | |
| dc.date.accessioned | 2021-09-13T06:23:31Z | |
| dc.date.accessioned | 2023-11-04T15:17:16Z | |
| dc.date.available | 2021-09-13T06:23:31Z | |
| dc.date.available | 2023-11-04T15:17:16Z | |
| dc.date.issued | 2020-12 | |
| dc.description.abstract | A railway interlocking system ensures safe train traffic in the railway line by monitoring and controlling its components, such as Computer Based Interlocking (CBI), signals, switches and track circuits. These components must prevent collisions and derailments of the train and their reliability directly affects the availability and safety of the railway network. This study analyzes the reliability, availability and safety of the interlocking control architectures and components by Markov and Reliability Block Diagram (RBD) methods based on the design and failure data of AA-LRT signaling systems. The first part of this study analyzes and compares the reliability, availability and safety of the one-out-of-one (1oo1), two-out-of-two (2oo2), two-out-of-three (2oo3) and double two-out-of-two (2*2oo2) systems of interlocking control architectures. This helps to choose appropriate interlocking control architecture for AA-LRT. The results show the more advantageous of a double 2oo2 system that is the current control architectures of AA-LRT with high requirements in both safety (0.999999993) and availability (0.9999999999997). When one part of the redundant 2oo2 system is in active mode, another works in standby mode. If a failure occurs in the active mode, the process continues by the standby subsystem. The second part of the study evaluates the reliability and availability of AA-LRT interlocking system components. This helps to give priorities for critical components and to determine technical and non-technical manpower planning. The results show that CBI has the highest reliability (0.8922) and availability (0.9999), and the axle counter has the lowest reliability (0.1059) and availability (0.9986) after 500 hours of operation. According to the analysis, 92.15% of failures are axle counters failure and this affects the normal operation of both East-West (EW) and North-South (NS) railway lines. The main reasons for axle counter failures are power system and wheel sensor failures, it requires a stable power supply and swift wheel sensor maintenance. | en_US |
| dc.identifier.uri | http://etd.aau.edu.et/handle/123456789/27868 | |
| dc.language.iso | en_US | en_US |
| dc.publisher | Addis Ababa University | en_US |
| dc.subject | Interlocking System | en_US |
| dc.subject | Reliability | en_US |
| dc.subject | Availability | en_US |
| dc.subject | Safety | en_US |
| dc.subject | Markov | en_US |
| dc.title | Reliability, Availability and Safety Analysis of Addis Ababa Light Rail Transit Interlocking System | en_US |
| dc.type | Thesis | en_US |