• Proceedings of the KIEE Conference
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• 2007.07a
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• pp.2054-2055
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• 2007

이 논문에서는 철도전력시스템에서의 유지보수를 위한 고장률 분석에 관하여 설명하고 있다. 유지보수와 관련된 문제들은 시스템의 다른 부분과도 연관이 있어 기계적 사고의 위험성을 증가시킨다. 그러므로 설비는 교체와 예방정비를 겪게 된다. 여기서는 유지보수의 방법을 욕조곡선을 기반으로 정할 것이다.

• Journal of the Korea Safety Management & Science
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• v.17 no.3
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• pp.81-88
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• 2015

Infrastructure such as tracks, catenary, rolling stock and signaling systems, and close interface with the human factors of train drivers, shunting staff and maintenance staff are required for train operations. Safety management is the most essential part for the functioning of a train. In line with the safety management, each rail operator has a safety guidance system and the Ministry of Land, Infrastructure and Transport operates Railway Safety Inspector system. Safety Inspector System is to train employees working in the field to be aware of rules and regulations, and to improve identified risk factors. Hence, it is necessary to establish systematic training and inspection methods for safety guidance staff and make clear the roles and responsibilities of safety inspectors according to the Occupational Safety and Health Act, and safety instructors for several inspections according to the Railroad Safety Act.

• Proceedings of the KSR Conference
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• 2008.11b
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• pp.1494-1500
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• 2008

Life cycle of the rolling stock is normally 20 to 40 years, though there is some difference in accordance with each vehicle. Maintenance cost is over the twice of purchasing price. and also it is true that precise statics is not managed properly except for some developed countries due to the difference of maintenance method, skills. After KORAIL introduced ERP system in 2007, maintenance cost is managed by type of cars, by unit. but, afterwards it should be controlled as an index and also more precisely. it is the best pending issues to make train maintenance efficiency, to utilize accumulated indexes. I want to attribute to train maintenance efficiency by analysing what is the problems in the present maintenance method.

• Proceedings of the KSR Conference
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• 2008.11b
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• pp.638-644
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• 2008

Mungyeng line(Jupyung${\sim}$Mungyeng) was closed due to a rapid decrease in demand in 1995. However, as the rail transportation demand is expected to increase with the plan to develop a tourist resort and a traffic network in Mungyeng area, it is required to forecast future demand to meet the change of transportation environment in this region. This study predicts the rail transportation demand and analyzes financial benefit in operator's side in case of reopening this line, based on nation-wide traffic volume data from Korean Transportation Database(KTDB). The results of this research can be applied to not only establishing a train operation plan also improving customer service. Moreover, Korail will have an opportunity to develop new business by linking train service to tourist attractions around the Mungyeng area.

• Proceedings of the KSR Conference
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• 2008.11b
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• pp.1570-1594
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• 2008

Nowadays there are lots of changes in the domestic railroad industries because of the reorganization in the industries, operation of KTX and expansion of city train in local areas. To cope with these changes effectively, domestic & abroad safety guideline and regulation were investigated and reviewed by railroad safety technical development project. Based on this project, domestic rolling stock safety regulation was established in the July and December on 2005. It's been a 3 years after 2005 and to confirm whether there are some problems to applicate the regulation in the field like korail, the necessity of reviewing the regulation gains force. In this study, to improve the field application in rolling stock safety regulation, we investigated the results of integrated railroad audit system and internal safety regulation system in a train operator and also collected the opinions from train manufacturer. Then through the result of investigation and collection of the opinions, we proposed the amendment to the rolling stock safety regulation.

• Korea Trade Review
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• v.44 no.4
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• pp.153-168
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• 2019

The logistics industry is changing with the diversification of demand and related technology development. Thus, the transportation system is also changing to social problems and environmental damage, and the importance of rail freight is increasing with changes in the international logistics environment. This study analyzes railway freight competition structure using freight volume and suggests improving the competitiveness of railroad freight. To achieve the research purpose, this study was conducted using the Hirshmann-Herfindahl Index(HHI) and Location Quotients(LQ) method. As a result, the concentration trend of railway trends has increased from 0.213 to 0.238 during the last 9 years, and LQ analysis has enabled the identification of local competition lines by item. The study result confirmed that policy measures on railway freight system, railway infrastructure construction and railway operation are necessary to enhance railway competitiveness.

• The Transactions of the Korean Institute of Power Electronics
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• v.25 no.6
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• pp.490-495
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• 2020

The power loss of large-capacity systems using single-phase inverters has attracted considerable attention. In this study, optimal switching sequence model prediction control at a low switching frequency is proposed to reduce the power loss in a high-power inverter system, and a compensation method that can be utilized for model prediction control is developed to reduce errors in accordance with sampling values. When a three-level, single-phase inverter using a switching frequency of 600 Hz and a sampling frequency of 12 kHz is adopted, the power factor is improved from 0.95 to 0.99 through 3 kW active power control. The performance of the controller is also verified.

• Proceedings of the Korean Geotechical Society Conference
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• 2010.03a
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• pp.208-212
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• 2010

The high-speed railway consists of tracks, gravel ballast and subgrade, and the dynamic load is passed to subgrade through track and gravel ballast. The relaxation condition of the gravel ballast is able to be evaluate relatively and to be repaired through a continuous management, but it is difficult to evaluate the condition of subgrade, which is final part of supporting dynamic load and to repair it when made a problem. The gravel ballast and subgrade are evaluated by determining shear wave velocity. To evaluate ballast and subgrade, a good method to determine shear wave velocity is a non-destructive experiment such as surface wave tests providing a prompt experiment because an experiment in railway has a lot of tests which are carried out following railway directions and needs to prevent damage of the system. In general, a railway has limitation of an experimental space by narrow width, sleeper and etc., and background noise by a reflector exists. The existing surface wave tests need a minimum space, and it is difficult to get a reliable test results on account of background noise effect. Therefore, it is difficult or impossible to apply to existing surface wave test of subgrade and ballast. In this study, the HWAW method is applied to determine a shear wave velocity profile of the underground. The HWAW method is the experiment which is able to be carried out on a narrow space, and it determines share wave velocity of a site by measuring the wave from surface sources on the same spot. In addition, it removes effects of background noise accordingly to a signal processing using harmonic wavelet transforms, so it is useful to evaluate subgrade of a high-speed railway in the narrow space and the situation of background noise. In order to check an application of the HWAW method, an experiment is carried out on a high-speed railway field and a test result is compared to boring results.

• The Journal of The Korea Institute of Intelligent Transport Systems
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• v.16 no.1
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• pp.64-77
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• 2017

Domestic railway station calculates average number of passenger per day by considering future regional society and development of industrial economy etc, is carrying out designs on railway station scale. However, problems are being suggested situationally because selected average passenger data does not consider passengers having been diversified for a year. For representative example, confusion of Gwangju-Songjeong Railway Station got worse due to passengers whose number is more than original plan since the opening. Therefore, this study quotes the concept of design hourly factor using in designing roads to consider passengers having been diversified for a year in railway field. In order to calculate factor, collecting railway passenger data and also estimate, reliability verification were executed by using exponential model and 3rd equation model. As a result of deducing design hourly factor through inflection point calculation, utilizing exponen tial model is analyzed to well reflect the value of design hourly factor on railway passengers.

• Proceedings of the KSR Conference
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• 2010.06a
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• pp.72-79
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• 2010

The significant of continuous welded rail (CWR) management is growing because KORAIL has the plan to convert the whole of conventional railway lines into CWRs through continuous activities since constructed the CWR track with 1.8km in Gyeongbu line in 1966. The CWR recently is needed a efficient management method because it is difficult to manage the CWR by the poor of technic and equipment, limited maintain labor force and shorted the maintain work time of CWR caused by industrialization, greenhouse effect and global warming In this point, The 70ton Tenser's which is using in the rail site has been analysised with no extra tenser's capacity in case of the under low temperature and exceed the length of 1km as a result of reviewing the CWR-related rules and standards, a series of records of safety accidents, operation obstacles, and the situation of broken rails published by KORAIL, existing rail temperature measurements, and CWR researches. Therefore avoid the excessive plan of the first set-up section, choice the proper time in the normal temperature that is possible to weld the rail, turning the difference of rail temperature and Installation temperature down is desirable.