• Journal of the Korean Society for Railway
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• v.11 no.3
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• pp.240-247
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• 2008

Recently, railway corporations have built maintenance information systems and collected failure and maintenance data. For example Seoul Metropolitan Rapid Transit Corporation (SMRT) built the Electric Motor Unit-Information System (EMU-IS) which is the first maintenance information system in Korea. It has been operated from August, 2000. This paper deals with a case study on determining maintenance interval through reliability analysis using EMU-IS fault data. Door system is considered for the case study in which reliability is evaluated for operating time and distance and the overhaul interval is determined.

• Proceedings of the Korea Air Pollution Research Association Conference
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• 2003.11a
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• pp.421-424
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• 2003

서울지하철은 총연장 286.9km에 1일 4226회의 운행회수 그리고 대중교통수단 중 총 34.1％의 최다 수송분담율을 담당하고 있다. 서울시의 도심교통문제 해결 방안으로 시민들에게 대중교통 이용을 적극적으로 권장하고 있으나, 지하철 역사의 환경문제는 답보 상태를 유지하고 있는 것이 현실이다. 지하철내의 먼지문제는 이미 심각한 사회문제로 대두된 지 오래이며 이를 개선하기 위하여 지하철공사와 도시철도공사에서는 환기시스템의 개선, 환기 및 공기정화시설의 설치 그리고 잦은 물청소실시 등을 시행하여 오고 있어 그간 상당한 효과를 이룬 것도 사실이다. (중략)

• Journal of the Korean Society for Railway
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• v.12 no.2
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• pp.267-275
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• 2009

Max-plus algebra is a nonlinear system comprised of two operations, maximization (max) and addition (Plus), which are corresponding to the addition and the multiplication in conventional algebra, respectively. This methodology is applicable to many discrete event systems containing the state transition with the maximization and addition operation. Timetable with connection is one of such systems. We present the method based on max-plus algebra, which can make up timetable considering transfer and analyse its stability and robustness. In this study, it will be shown how to make up the timetable of the urban train and analyse its stability using Max-Plus algebra.

• Journal of the Korean Society for Railway
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• v.15 no.4
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• pp.381-387
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• 2012

This paper is aimed to analyze the achievements of the Tunnel Monitoring System(TMS), implemented in Seoul subway L5~L8, and to find out improved methods. By introducing the TMS, it is possible to inspect tunnel facilities for 24 hours a day while trains are operated. The inspection capability could be expanded, the accuracy was improved, and the cycle was shortened. The efficiency of manpower was improved and the surplus manpower could be used for other tasks of facilities maintenance. As a result, by introduction of the TMS, the amount of tunnel maintenance was increased by 225% and the train service troubles caused by facility problems were decreased by 53%.

• Journal of the Korean Society for Railway
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• v.19 no.3
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• pp.397-407
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• 2016

This study analyzed the efficiency change and the factors affecting productivity change for the six railway operation corporations that are local public enterprises; study was performed with the DEA-CCR Model and Malmquist Productivity Index, using data collected from 2010 to 2014. Since it was not feasible to collect data on the operating expenses and the number of employees of each of the lines, the efficiencies of each operation corporation were analyzed by integrating the operation corporations, and the Malmquist Productivity Index was used to investigate the trend of the periodical productivity change. Average efficiency for urban railway operation corporations was found to be higher in the case of the bigger corporations. In 2014, the Seoul Metro and the Daejeon Metropolitan Express Transit Corporations were analyzed and found to be the most efficient operation corporations. The Malmquist Productivity Index was used to determine the periodical change; the average MPI was 1.06, with a continuous increase of productivity. The analysis showed that changes of technology were generally more obvious than change of technology efficiency for all six operation corporations.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.26 no.4D
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• pp.679-686
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• 2006

Recently, the city railway in the Seoul Metropolitan Area (SMA) has offered a low quality of service as a passage time, because it was operated slowly. So, the people who live in modern society are not satisfied about passage time, therefore, this study tried to make that the subway in the SMA becomes a more functional and effective wide-area-transportation-network through an express train introduction's method which examined cases from abroad and current system. and then presented how express train could be applied to current system. In a case study, We used the An-San Line and Su-In Line as a examples and developed a schedule which can minimize the delaying time of subway by using Branch & Bound Algorithm. The train operational plan was loaded to consider a railroad siding, Obtained site, and the dispatch interval(three to ten minutes) for the express and local lines and finally, We presented an alternative operational plan which made by those factors.

• The Journal of the Convergence on Culture Technology
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• v.5 no.4
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• pp.439-444
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• 2019

In this paper, the seismic performance evaluation of the subway lines 1~4 conducted from April 2010 to October 2013 for the existing structures that were not seismically designed based on the seismic design criteria of urban railways was studied. The detailed design of seismic reinforcement for the facilities requiring seismic reinforcement was summarized through the detailed design of the seismic reinforcement construction conducted from March to December 2018. As a result of the evaluation, 53.2km (total project cost of 322 billion won) of 141.5km of Lines 1~4 were considered to require seismic reinforcement, and finally, the company aims to secure a 100% earthquake-proof rate to withstand earthquake-scale 6.5 by 2020. This paper can be used as basic research data to evaluate and reinforce seismic performance of urban railways in the future.

• Proceedings of the KSR Conference
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• 2011.10a
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• pp.2573-2580
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• 2011

SMRT(Seoul Metropolitan Rapid Transit Corporation) changed PC-oriented office system to Smart-Phone oriented mobile office system(STnF: SMRT Talk & Flash), and provided smart phone to all staffs. STnF make it possible not only voice communication between staff, but also to input and inquiry all kind of information related to work(ex: Facility maintenance, Rolling Stock management, office management, Finance, human resource etc.) based on smart phone. STnF conquers the limitation of time and space. All staffs can commute to the site directly to reduce moving time and to share information between staffs, so SMRT improve speed and reliability of work by making a quick decision and action on the spot. After introduction of STnF, within 1 year, the equipment failure ratio fell to 47%. Mobile office system reduced and level-off the step of approval. so enhanced civil customer service. Quantification and scientific movement of work make it fast evolution and development. These business improvement make it possible to put more outstanding manpower on new business and R&D project, and this contributes to company's management effectiveness.

• The Journal of the Convergence on Culture Technology
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• v.5 no.4
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• pp.379-385
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• 2019

The purpose of this study is to investigate the damage status of wood sleepers on concrete track of urban transit at different locations and to analyze the causes of damages. In addition, the turnout maintenance history during the service period of about 24 years was analyzed in conjunction with the train passing tonnage and that was to compare the current repair history. The most frequent damage components were rail, tie plate, spike and wooden sleeper. And, the damage caused by the defect of the rail fastening system such as spike and tie plate according to the deformation of the wooden sleeper was analyzed as the main type of damage. As a result, the damage of track components of turnout system was on the increase because they are directly affected by the train passing tonnage. The supplementary points of the check sheet for current turnout maintenance were derived and the improvement proposal was suggested based on the research results.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.18 no.3
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• pp.493-500
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• 2017

Based on the data accumulated through EMU fault management, this paper examines the reliability of old railway car parts and proposes measurements to improve safety. Subway Line 7 of the Seoul Metropolitan Rapid Transit Corporation, auxiliary power unit (Static Inverter) of the EMU second version is a core equipment to supply power to various room-service units in cars and make an effect directly on passenger satisfaction. To analyze the pattern of failure throughout the field data over a long period of time, this analysis of statistics and reliability considers the operating environment and stress factors. This statistical analysis presents the correlation between failure and the temperature stress factors related to frequent failure occurring intensively in summer. In addition, throughout the analysis of the life of the IGBT inverter, the effect of the temperature stress factor was observed before and after the repair. As a result of an analysis of the optimal operating conditions considering two variations of EMU, such as variable load and outside temperature, a difference in the cooling capacity between the optimal operating conditions and frequent failure conditions was observed. Based on this analysis, this paper suggests a way to minimize cooling capacity difference for the optimal operational conditions.