• International Journal of Railway
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• v.6 no.2
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• pp.64-68
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• 2013

In recent years, the speed of a train has been recognized as one of the important factors to determine the competitiveness as a mean of transportation. In line with this, infrastructure improvements and enhancements are being made with increases in the speed of train. Accordingly, there is a need to establish plans for infrastructure improvements through a comprehensive analysis of signals, track/civil engineering, catenary and environment, etc. to improve the speed of a train of high-speed train service sections in Korea. This study proposes improvement plans for catenary systems by investigating the possibility of improvements through performance analysis of catenary equipment by speed increase based on the analysis on catenary systems in Gyeongbu high-speed line, and analysis the applicability of catenary improvements and economic feasibility.

• Journal of the Korean Society for Railway
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• v.8 no.6 s.31
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• pp.544-549
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• 2005

Nowadays, most of bridge networks are complete or close to completion. The biggest challenge railroad./highway agencies and departments of transportation face is the maintenance of these networks, keeping them safe and serviceable, with limited funds. To maintain the bridges effectively, there is an urgent need to predict their remaining life from a system reliability viewpoint. And, it is necessary to develop the maintenance models based on system reliability concept. In this paper, maintenance models are developed for preventive maintenance and essential maintenance by using system reliability and lifetime distributions. The proposed model is applied to an existing railroad bridge. The optimal maintenance strategy of this bridge is obtained in terms of services life extension and cumulative maintenance cost.

• Proceedings of the KIEE Conference
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• summer
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• pp.1304-1306
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• 2004

Recently, the study for development of system having affinity for environment is on investigation. This issue is also applicable to transportation system. This paper suggested the inductive power transformer used for the road/railway applied to contactless power transfer system. The two secondary windings, large gaped magnetic structure and horizontal alignment between primary and secondary coil for that transformer approach a process for improvement of contactless power transfer system performance.

• Proceedings of the KSR Conference
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• 2001.10a
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• pp.62-73
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• 2001

The scope of this study is focused on the survey of new logistics transportation systems in railroad and case studies of new systems such as piggyback system, bi-modal system swapbody, and double stack train(DST). Piggyback system, bi-modal system, swapbody, and double stack train are reviewed in term of technological validity and economic validity in Korea. Piggyback - trailer does pass loaded weight limits but does not pass train limits and can not utilize the existing freight cars. Piggyback - cargo trunk does pass all the criteria and could be developed by a domestic technology. But this study suggests to expand the length of train cars to 18.300mm for accommodation of two cargo trucks. Bi-modal system and swapbody do also pass. Double stack train could only pass the loaded weights and does not meet the train limit and the possibility of using existing freight cars. Domestic technology could not development DST, due to civil engineering construction limits and low standard height of electric line, which could not afford to operate DST.

• Proceedings of the KSR Conference
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• 2007.05a
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• pp.1297-1301
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• 2007

The indoor air quality guideline of public transportation means was prepared recently. therefore we consider a countermeasure for the indoor air quality improvement of public transportation means. In this work, air-cleaner with roll filter system which developed alternative of indoor air quality guideline. The develpoed roll filter system is two function. the first function harmoniously circulated to heating and cooling air through HVAC system and secondary function removed PM(particluatie matters) which re-scatting to passenger's movement and suppled from outdoor air. Filter media of roll filter system select optimum electret mesh filter out of many filter media. Selected filter media was performanced tests of pressure drop, collection efficiency and dust holding capacity. Finally developed roll filter system was performanced bench test.

• Proceedings of the KSR Conference
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• 2007.11a
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• pp.917-922
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• 2007

Electromagnetic suspension, the suspension system used for Maglev trains, is now being applied to urban and inter-city transportation systems, offering environmental benefits. This suspension system is actively controlled to stabilize the suspended vehicle as it runs over an elevated guideway, which, for various reasons, may have deviations in its height. For this reason, frequency responses of the suspension to height deviations must be predicted in the system design cycle. The equations of motion of the electromagnetic suspension employing the 5 state feedback control law are derived for frequency analysis. The results of this paper could be used to determine design requirements for the urban Maglev transportation system currently under development in Korea.

• Proceedings of the KSR Conference
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• 2009.05a
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• pp.1431-1440
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• 2009

A subway in Seoul has had a major role of public transportation after the opening of Seoul Subway Line 1 on August 15, 1974 and it has reached 34.7% of the transportation of Seoul citizens. The extended length of the subway system suppled with DC power in Korea is about 500km. In this system, the devices which are proper for regenerative power system are being required because of changeover from old braking and ATS signal system to regenerative braking and ATO signal system. In this paper, we reviewed the safety standards for the insulated hangers in overhead contact line. These hangers which have depended on foreign imports are being developed in Korea considering ease of demand and supply and economic effects.

• Proceedings of the KSR Conference
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• 2005.11a
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• pp.976-981
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• 2005

The Seoul subway line No.2 is the one of the busiest metro service line of the passenger transportation in Seoul metropolitan city. The number of the passengers served by the Seoul subway line No.2 is more than 1.9 million in a day according to the transportation reference of 2004, which is about $15\%$ of the whole population in Seoul metropolitan city. This is the reason why the Seoul Metropolitan Subway Corporation(SMSC) is implementing the refurbishment of the current ATS signalling system of Seoul Line No.2 into the most advanced ATO system with the continuous air-gap telegram transmission through the track circuit without any suspension of the train service either in when or in where, which is the first in the world in its attempt to refurbish the old signalling system under service without any suspension of the train operation.

• Proceedings of the KSR Conference
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• 2011.10a
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• pp.2456-2463
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• 2011

Conventional railways are less competitive than other land transportation means in term of speed, and thus users preference and transportation share for rail system are relatively lower than others. For example, most of the conventional lines except the Seoul~Busan corridor run at an average speed of 70 km/h or less, which imposes certain constraints on roles and functions as the trunk lines. In this regard, the speed of the conventional lines should be improved up to 200 km/h to gain competitiveness, promote balanced regional development and lead the era of low carbon green growth. As track system is one of the most important elements for the speed-up, it is critical to come up with optimum technical solutions. Improvement of ballast track structure with efficient track installation can provide structural stability for higher speed and ensure operational safety with lower maintenance efforts. Thus, this study focuses on consequences followed by the speed-up including increase of load imposed on the track and impacts on track components, and provide solutions for track maintenance by analyzing impact on the track structure by speed. Also, it compares ballast and concrete tracks under designing and construction and considers how to meet needs for passengers comfort and environmental requirements as a strategic approach.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.37 no.11
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• pp.1371-1377
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• 2013

In this analysis, a method is presented to calculate the critical speed of a railway vehicle by using a multibody dynamic model. The contact conditions and contact forces between the wheel and the rail are formularized for the wheelset model. This is combined with the bogie model to obtain a multibody dynamic model of a railway vehicle with constraint conditions. First-order linear dynamic equations with independent coordinates are derived from the constraint equations and dynamic equations of railway vehicles using the QR decomposition method. Critical speeds are calculated for the wheelset and bogie dynamic models through an eigenvalue analysis. The influences of the design parameters on the critical speed are presented.