• Journal of the Korean Society of Safety
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• v.34 no.1
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• pp.108-114
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• 2019

Unattended Train operation(UTO) requires higher safety target than other systems, since all train operations are automatic. The system provider to deliver without accident or failure, and the operator to transport passengers without accident by putting all trains supplied, including them, into service. Safety rates without such failures can be represented as indicators of RAMS, among which availability is continuously controllable to achieve the target, with a clear target. Availability is often required by the licensee from the initial stage of the project to demonstrate that the request for proposal (RFP) is usually specified and to maintain separate availability targets at the operational stage. In particular, unlike unmanned operation light rail in complex systems, simple formulas are often presented to facilitate verification at each stage. This paper presents this method of usability calculation in an integrated manner at all levels and analyzes the existing usability values to ensure reliability of the availability formula for integrated use in unmanned light rail systems.

• Journal of the Korean Society of Safety
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• v.36 no.2
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• pp.1-9
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• 2021

The 8200-unit electric locomotive, which is a high-efficiency multipurpose electric locomotive, is a German model, namely BR152 series ES64F, and it is manufactured to suit the operating conditions in Korea. Since 2003, 83 locomotives have been introduced in Korea, and they have been operating in the general railway sector for both passenger and freight transport. Although more than 15 years have passed since their first introduction, owing to the characteristics of vehicles introduced overseas, responding promptly to failures has been difficult owing to problems related to factors such as transfer of technology and procurement of parts for maintenance. Furthermore, there have been difficulties in operating the locomotives on the basis of the manufacturer-recommended time-between-overhaul (TBO) cycle. Therefore, a new TBO should be determined. To support the development of a reliability-based maintenance system, this study conducted a reliability and TBO analysis by using failure data obtained from KOVIS, and future management measures are presented.

• Proceedings of the KSR Conference
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• 2007.11a
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• pp.191-196
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• 2007

This paper is reviewed RAM(Reliability, Availability and Maintainability) data table utilized for RAM data management to Urban Maglev Transit. As railway systems become more complex, the RAM requirements are reinforced to ensure that a design meets Reliability, Availability, Maintainability criteria. Therefore, it needs the efficient management for RAM data of railway system to meet RAM target. At this study, RAM data management format is suggested to ensure reliability and maintainability based on acquired experience for overseas rolling stock. This RAM data table and FMECA(Failure Mode Effect Criticality Analysis) table are useful to the calculation of MTBF(Mean Time Between Failure), MTBSF(Mean Time Between Service Failure) and Maintainability. Also, this RAM management table will be efficient to improve the RAM evaluation to Urban Maglev Transit.

• Proceedings of the KSR Conference
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• 2003.10c
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• pp.65-72
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• 2003

In order to evaluate the strength of carbody structures of railway rolling stock made of laminated fiber-reinforced composite materials, total laminate approach was introduced. Structural analyses were conducted to check the basic design of the hybrid composite carbody structure of the Korean Tilting Train eXpress(TTX) with the service speed of l80km/h. The mechanical tests were also conducted to obtain strengths of composite laminates. The results shown that all stress components of composite carbody structures were inside of failure envelopes and total laminate approach was recommended to predict the failure of composite carbody structures at the stage of the basic design.

• Proceedings of the KSR Conference
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• 2008.11b
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• pp.1562-1569
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• 2008

In this paper, the study on development of an applicable logic on the characteristics of Rolling stocks will be proposed. In general, this logic which means decision logic or LTA(Logic Tree Analysis) is used to analyze how the failure mode have an effects on the system. The effect would be categorized as safety, operational, economical, etc. To do this, based on the typical logics which have been applied to other industries, such as plants, aero, etc. This paper emphasizes two crucial parameters that is one cost the other customer service, that have an important role in railway system operation. In conclusion, as mentioned above as the logic for which could be effectively applied for the railway system(RST) would be developed.

• Proceedings of the KSR Conference
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• 2011.05a
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• pp.1636-1641
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• 2011

Typically Korea Railroad is executing the limited inspection and general inspection about passenger car by mileage and the time elapsed.(ex. one year, two years) These types of inspection system continue from the beginning of the railroad operation of the steam locomotive age to present. According to the rolling stocks modernized and improved, mileage and the time elapsed for periodical inspection has been expanded but the basic maintainability system of rolling stocks is not that different from the past. This fact needs verification that modern inspection method is right from various fields. In this paper, we analyze the data that we get the maintenance record from Korea railroad company about periodical inspection and failure. Next to considering the correlation of periodical inspection with failure based on analyzed data for watching periodical inspection effects. And we desire to need efficient rolling stock maintenance system better than fixed periodical inspection.

• Journal of the Korean Society for Railway
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• v.13 no.2
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• pp.159-165
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• 2010

In this paper the TRMS (Tilting Rolling-stock Maintenance System) that applies the concept of RAM (Reliability, Availability, and Maintainability) and RCM (Reliability Centered Maintenance) to Preventive and Corrective Maintenance Policy for TTX (Tilting Train Express) will be discussed. We will briefly introduce the RCM concepts and discus show these concepts and procedures are implemented in the TRMS S/W. In the TRMS S/W there are four modules, System and Operations Information Module, FMECA(Failure Modes, Effects, and Criticality Analysis)module, RAM Information Module, and RCM Analysis Module. The System and Operations Information Module provides the user interface for collection of systems and operations related data and the FMECA module provides a groundwork for the RCM analysis. The algorithms to calculate the reliability and failure rate for Weibull distribution and formulae to calculate the task intervals and task costs are proposed in the RAM and RCM Analysis Module respectively. There is a good possibility of applying RCM to other rolling stock maintenance systems if the benefit that RCM can brings to the maintenance world is fully recognized.

• Proceedings of the KSR Conference
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• 2005.11a
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• pp.258-263
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• 2005

The purpose of this research is to present a practical method for efficiently monitoring a reliability growth process using AMSAA(Army Materiel Systems Analysis Activity) reliability growth model. The presented method is viable for identifying failure modes, incorporating design changes and monitoring reliability progress on an on-going basis during the early stages of a product development program. According to the Application Guide for EN 50126(RAM part for Rolling Stock), reliability growth monitoring is essential part of the main tasks of design phase in RAM growth monitoring. Implementation of reliability growth management program will provide very useful information on concept selection, product/process reliability, and cost effectiveness without too much time, money and engineering effort being spent on the development of failure suspect parts.

• Composites Research
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• v.17 no.1
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• pp.18-28
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• 2004

In order to evaluate the strength of carbody structures of railway rolling stock made of laminated fiber-reinforced composite materials, total laminate approach was introduced. Structural analyses were conducted to check the basic design of hybrid composite carbody structures of the Korean Tilting Train eXpress(TTX) with the service speed of 180km/h. The mechanical tests were also conducted to obtain strengths of composite laminates. The results show that all stress components of composite carbody structures are inside of failure envelopes and total laminate approach is recommended to predict the failure of hybrid composite carbody structures at the stage of the basic design.

• Journal of the Korean Society for Railway
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• v.20 no.5
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• pp.569-576
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• 2017

The electromagnetic valve of pneumatic doors of EMUs has a high failure rate due to air leakage because it supplies air on and off to operate the doors repeatedly. The electromagnetic valve is a very important safety component for which a very high reliability is required because failure makes it impossible to operate the passenger cars. However, domestic urban railway operators maintain electronic valves of the EMU door under a fixed cycle with a spare period according to the full overhaul cycle of the EMU. An improvement of the current maintenance cycle was suggested based on the reliability function and mission reliability. Using the statistical program MINITAB for the operational data of EMU line 6, we analyzed the characteristics of the fault distribution and derived the shape and scale parameters of the reliability function. If we limit the specific reliability probability to under a certain failure rate and calculate its statistical parameters, we can calculate the allowable inspection period with mission reliability. Through this study, we suggested a maintenance period based on RCM (reliability centered-maintenance) to improve the reliability of electromagnetic valves from 68% to 95%.