• Transactions of the Korean Society of Mechanical Engineers A
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• v.37 no.9
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• pp.1099-1107
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• 2013

This study proposes a weight reduction design for urban transit, specifically, a Korean EMU carbody made of aluminum extrusion profiles, according to size optimization and useful material changes. First, the thickness of the under-frame, side-panels, and end-panels were optimized by the size optimization process, and then, the weight of the Korean EMU carbody could be reduced to approximately 14.8%. Second, the under-frame of the optimized carbody was substituted with a frame-type structure made of SMA 570, and then, the weight of the hybrid-type carbody was 3.8% lighter than that of the initial K-EMU. Finally, the under-frame and the roof-panel were substituted with a composite material sandwich to obtain an ultralight hybrid-type carbody. The weight of the ultralight hybrid-type carbody was 30% lighter than that of the initial K-EMU. All the resulting carbody models satisfied the design regulations of the domestic Performance Test Standard for Electrical Multiple Unit.

• Journal of The Korean Society For Urban Railway
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• v.6 no.4
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• pp.249-257
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• 2018

The number of deaths for railway traffic accidents is mainly caused by working close to the track, or when unauthorized passage pass through the track. The safety fences are being used to ensure safety for workers close to the track, and to improve the efficiency of the work, without interfering with the passage of trains. However, a safety fence for railway tracks needs to be examined to see if it will interfere with the passage of trains. The purpose of this study is to analyze the safe distance between train and safety fence developed in Korea. In addition, the lateral load condition of wind pressure by trains is estimated and numerical analysis is carried out according to the installation intervals of railway safety fences. It has been confirmed that the proper spacing between the train and the railway safety fence should be at least 200 mm from the vehicle limit, and that the proper spacing of railway safety fence must be calculated in consideration of the wind pressure by trains.

• Proceedings of the KSR Conference
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• 2011.05a
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• pp.594-600
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• 2011

"The guidelines on the management of indoor air quality of public transportation" was enacted in December 2006 due to the fact that the interest and demand of improving the air quality for citizen using public transportation have been increased. Thus this research has considered what has influenced on the passenger cabin HVAC as well as the improvement of customer service as we proceed the study for better indoor air quality inside of the train by developing the module of cleaning air system for pollutants of a car air.

• Proceedings of the KSR Conference
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• 2011.10a
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• pp.2998-3006
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• 2011

This paper is about the relations between the electric multiple unit and ESS(Energy Storage system, here after) applying bi-direction Buck-Boost Converter. ESS may be possible to suppress the line voltage drops and the power loading fluctuations and to save the regeneration power lapses. This paper confirm for simulation that ESS reusing regenerative power generated during braking in train. Also, presents the influence of regenerative power variation of train and catenary acceptability for energy saving obtained by applying the ESS to Daejeon Metro line 1.

• Proceedings of the KSR Conference
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• 2011.10a
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• pp.1049-1058
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• 2011

This paper suggests blending time adjusting method of braking command characteristics management and Set value test for optimizing of braking deceleration to enhance the precise position stopping. This method minimizes pneumatic-braking degree deviation by characteristics management, and secures braking stability at braking. By Set value test method, braking blending characteristics are analyzed accurately. And by optimal timing tuning at braking blending, It enhanced the precise position stopping with stabilization of deceleration To demonstrate the usefulness of these suggestion, I modeled for Deajeon Line #1. And through comparison with case of related companies, the proposed method which this paper suggested is proved to be superior to others.

• Proceedings of the KSR Conference
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• 2011.10a
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• pp.621-629
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• 2011

Uniaxial and biaxial torsional fatigue tests were conducted on the samples extracted from urban railway wheel steel. Ultimate and yield strengths of the steel were 1027.7 MPa and 626 MPa, respectively. The uniaxial fatigue limit was 422.5 MPa, corresponding 67% of the ultimate tensile strength. The ratio of ${\tau}_e/{\sigma}_e$ was 0.63. Fatigue strength coefficient and exponent were 1319.5 MPa and 0.339, respectively. Maximum principal and equivalent strain were found to be adequate parameter to predict fatigue lifetime of the steel under multiaixal fatigue condition.

• Proceedings of the KSR Conference
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• 2011.10a
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• pp.142-149
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• 2011

The basic of installing smart air cleaner in railway system is improvement of continuous real time sensing technologies. And building smart air cleaner in railway system with IT is needed. When smart air cleaner in railway system is developed, the installation of sensor which is for measuring air quality in the passenger room and setting revolution cycle of filter which is for removing fine dust is very important. In order to install it in a train which is now running, after making of standard test certification and verification of product's stability with enough self-test, application test will be performed.

• Journal of the Korean Society for Railway
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• v.9 no.5 s.36
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• pp.577-581
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• 2006

Urban transit operation corporations perform repetitive work to investigate the EMU, electric multiple unit, by some fixed maintenance cycle. The quality of maintenance work usually depends on workers' know-how. Though some information to support the maintenance work is digitalized and provided to workers, it is not great help to them because of its non systematic structure. The information includes drawings, manuals, work results, work history, fault history, etc. The maintenance workers want to access the information anytime anywhere, and make an effect to promote the efficiency of maintenance for EMU. But it is difficult to achieve that without some structured information system which is able to use in work area. So we develop maintenance information system for EMU for about 4 years from 2002 to 2005. In this paper we present the configuration and characteristics of this system, and the results of the evaluation test. We install the system in two depots, Changdong and Jichuk, belonged to SeoulMetro to evaluate its efficiency and estimate its economic benefits.

• Proceedings of the KSR Conference
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• 2007.05a
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• pp.932-935
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• 2007

According to Urban Railroad Act, trains can be operated only after they take The Urban Transit Performance Test. There has been Performance Tests for the trains which has been manufactured since 2000, but it is nearly impossible to utilize the Performance Test results other than the original purpose due to the fact that they are not organized in detail, In addition, test steps have difficulty using the former test results. Thus, test results must be computerized and made into database to make the best use of them and to carry out efficient and dependable tests. For this purpose, this paper analyzes the task and the procedure of the performance test on trains. On the basis of the analysis results, this paper checks the availability of the computerized information and the possibility of improving the task concerned

• Proceedings of the KSR Conference
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• 2010.06a
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• pp.104-109
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• 2010

Management innovation as a strategic alternative to create competitive advantages in the global market, is being actively progressed by conglomerates such as Samsung, LG and Toyoda as they cut a brilliant figure in the 21 century by using various innovation methods. However, the domestic railway sectors, in particular urban railway depots have neglected management innovation as they undertake Operation and Management in non-competitive settings of a corporate enterprise. This paper analyzes the critical success factors that have switched the most obsolete depots to a benchmark model for domestic railway depots based on the remodeling businesses undertaken in Gunja rolling stock maintenance office, Korea's first urban railway depot, along with 5S 6sigma program.