• International Journal of Railway
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• v.7 no.1
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• pp.8-15
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• 2014

Recently, in the total railroad construction field, concrete slab tracks have been adapted in place of ballast tracks. Because ballast tracks need frequent maintenance and are difficult to handle due to increasing maintenance costs, eventually concrete slab tracks were selected as an alternative. However, owing to the hydration heat reactions and temperature-affected shrinkage of the concrete, a variety of studies to solve maintenance problems related to concrete slab tracks are underway. This study analyzed characteristics of TQI values evaluating track irregularity, investigated the relationship between crack progress and TQI, and then evaluated the correlation between the two values. Through our analysis, we found that there is a need to supplement the problems of the current method and develop a track evaluation index which takes cracking into account. We also concluded that TQI is the main decision-making tool in track maintenance.

• Proceedings of the KSR Conference
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• 2004.10a
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• pp.1419-1424
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• 2004

Railway safety is based on a risk analysis and safety assessment for the whole railway system as human, train, electric, signaling, operation, maintenance and etc. Therefore in this study, after investigating the accidents happened in electric railway on Choongang line for 5 years, from '97 to '01, a Data-Base was made through a cause and result analysis. In consideration of economic loss and human resources damage, a risk assessment for electric railway was also performed.

• Proceedings of the KSR Conference
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• 2011.10a
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• pp.907-914
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• 2011

It has used for Rolling Stock Maintenance a number of maintenance system applied RCM in Railway(Korea Railroad Corporation, Seoul Metro, Korail Airport Railroad Corporation, etc) so far. Some institutions has been using develop Computational System including reliability process. A majority of the system has computerized maintenance work, but it is shown that developed focus on administrator and developer not user. SMRT(Seoul Metropolitan Rapid Transit Corporation) has developed computational system for maintenance in the '90s and saved many data about Maintenance Historical Data. However, this system reached the limits application of this data. Maintenance of computer systems is managed directly by the field staff and to introduce Reliability-centered maintenance SMRT was continually reviewed system development trends and supplement the existing system. To successfully operate RCM program should be gained full support in the whole company and field communicate, secure a reliable data from field and the most important take a patience. Our corporation will operate and develop successful RCM thorough review of these problems in the future.

• Journal of the Korean Society for Railway
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• v.10 no.2 s.39
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• pp.231-242
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• 2007

As railroad industry faces the new Renaissance era, effective and efficient maintenance methods for rolling stock operation are required with advanced railroad technology. All kinds of railroad systems such as high-speed long-distance train, metropolitan mass transit and light rail require systematic maintenance technology in order to maintain the safe railroad operation. Simulation models for regular operations of the example maintenance center are developed. In this study, standard maintenance procedures, layout, equipments, and number of workers of Siheung Metropolitan Railroad Maintenance Rolling Stock Depot are considered. The proposed simulation models are developed using simulation package ARENA. After simulation, four types of observations are analyzed. First, the bottleneck operation is identified. Second, the relationship between maintenance center size, number of workers and cycle time is analyzed. Third, the scheduling performances between PERT/CPM and Critical Chain Project Management(CCPM) are compared. Lastly, the simulation results according to worker's working coverage shows expanding the worker's coverage decreases the cycle time and increases throughput per train. However, workers are to be fully trained to do multiple skill work.

• International Journal of Safety
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• v.9 no.2
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• pp.29-34
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• 2010

When doing maintenance works at the trackside of railway, the method which delivers information on approaching of train to maintenance workers through alarm devices such as the flag or indication light, etc., is being used by locating persons in charge of safety alarm in addition to the maintenance workers at fixed distances in the front and rear of the workplace. Workers maintaining at the trackside may collide with the train since they cannot recognize the approach of train although it approaches to the vicinity of maintenance workplace because of the sensory block phenomenon occurred due to their long hours of continued monotonous maintenance work. The clash or rear-end collision accidents between many maintenance trains called motor-cars can be occurred since there are cases where the signal systems for safe operation of motor-car such as track circuit etc. are blocked or not operated normally. We developed the new safety equipment for protection of trackside maintenance workers using radio frequency signals and bidirectional detection mechanism. The developed safety equipment must analyze the several operational mechanism for each different operation situations. In this paper the analysis results are represented.

• Journal of the Korean Society for Railway
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• v.10 no.5
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• pp.520-526
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• 2007

본 논문에서는 한국형 틸팅열차의 유지보수 활동을 위해 신뢰성기반유지보수체계를 제안하였다. 열차시스템을 3단계의 교체 부품 단위로 분류하고, 각 단위에 대해 기능블록도를 작성한 후 고장모드 영향 분석을 실시하였다. 각 단위의 심각도를 결정한 후 유지보수 정책을 제안하였으며, 틸팅열차를 위한 유지보수 기준을 정하고, 실제 사례를 제시하였다. 제안된 신뢰성기반유지보수체계는 기존 유지보수 체계와도 호환성을 갖고 있으며, 안전성 향상과 유지보수 활동 효율화에 기여할 수 있다.In this paper, a reliability centered maintenance (RCM) system is proposed to perform maintenance action for Korean Tilting Train. The train system was divided into line replaceable units up to three steps. Functional block diagrams were drawn and failure mode effect analysis for the units was carried out. The criticality of each unit was determined and a maintenance policy was proposed. Maintenance and repair criteria for the tilting train were determined and an example was presented. The proposed RCM system is compatible with the previous maintenance system and contributes to improvement of safety and efficiency of maintenance action.

• Journal of the Korean Society for Railway
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• v.16 no.3
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• pp.183-188
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• 2013

The purpose of maintaining rolling stock is to perform train service without failure during operation. It is not possible to prevent failure, however, by using periodic preventive maintenance methods, because new rolling stock is made from many electric components and requires the application of IT skills. RAMS (Reliability, Availability, Maintainability, Safety) methods have consequently been applied to new manufactured rolling stock in KORAIL since implementation of the KTX. With this approach it is possible to verify the reliability at the operating stage, and RCM (Reliability Centered Maintenance) methods for maintenance have been applied to manufactured rolling stock since the beginning of KTX service. A RCRM (Reliability Centered Rolling-stocks Maintenance) system suitable for the characteristics of rolling stock and operational factors is introduced in this paper.

• Journal of the Korean Society for Railway
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• v.15 no.6
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• pp.566-571
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• 2012

The door systems in urban railway vehicles, through heavy maintenance checks by six years, 75 parts for 34 part types in 75 units have to be replaced periodically, and the remaining 68 parts for 40 part types to be replaced occasionally based on the necessity. Even though this process makes the door systems almost to be initial status, the systems have complicated mixes of components with new parts and used and then have different property from the original ones. This study suggested a burn-in test as a subsidiary tool to improve the reliability of urban railway vehicles, and suitable for testing conditions and the proposed new target value.

• Proceedings of the KSR Conference
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• 2009.05a
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• pp.495-504
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• 2009

As the Reliability Centered Maintenance(RCM) is being studied, maintenance tasks can be performed effectively through the Risk Priority Number(RPN) evaluation about the components in the system. The RPN is usually calculated through arithmetical operations of three values, Severity, Occurrence, and Detection for each facility. This RPN provides information that includes risk level of the facility and the priority order of maintenance tasks for facility. However, if there is no sufficient historical failure data, it is difficult to calculate the RPN. In this case, historical failure data from other sources can be used and apply this data to korean railway system. In this paper, it is proposed that a new methodology to model the failure rate as a fuzzy membership function. This method is based on failure data from other sources by means of the fuzzy theory and the expert opinion system. And considering assessment tendency of each expert, distortions that happened when the failure rate of facilities is estimated were minimized. This results determine Occurrence values of facilities. Taking advantage of this result., the RPN can be calculated with Severity and Detection of facilities by using the fuzzy operation. The proposed method is applied the rail-way power substation.

• Proceedings of the KSR Conference
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• 2007.05a
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• pp.438-443
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• 2007

In the recent railway construction, the concrete slab track is highlighted as the maintenance-free track and the main stream is moving from ballasted track to concrete slab track. However, in spite of many merits of concrete slab track, the higher noise generated from the concrete slab track is a troublesome question to solve and, by this reason, many studies on noise reduction of concrete slab track are carried out. The railway noise can be classified into the reflection noise emitted from wheel/rail contact and the structure-borne noise transmitted through railway structures. In this presentation, we would like to introduce an example of the successful reduction of structure-borne noise at track retrofitting to maintenance-free concrete slab track in elevated Changdong Station which was built with ballasted track on Rahmen structure.