• Journal of the Korean Institute of Gas
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• v.15 no.3
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• pp.31-38
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• 2011

In this study, we investigate simulation studies to confirm the removal of smoke through ventilation when the subway car is on fire and stopped in an underground subway tunnel, by using Fire Dynamics Simulator (FDS) which is being upgraded by NIST. The structure of subway tunnel and train for simulation modeling are based actual data from Seoul metropolitan subway. The main purpose of this study is to assure the removal efficiency of the ventilation when changing the ventilation capacity between 2.0 m/s and 3.0 m/s. The results of the study shows that carbon monoxide (CO) and carbon dioxide ($CO_2$) are reduced by about 35% as the ventilation capacity is increased by 0.5 m/s. This study also performs the grid sensitivity verification of FDS for improved accuracy of the results. To find the effective size of the grid, three cases are simulated and the results are compared.

• Journal of Korean Society for Atmospheric Environment
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• v.21 no.6
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• pp.639-647
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• 2005

A single particle analytical technique, named low-Z particle electron probe X-ray microanalysis (EPMA), was applied to characterize samples collected at a subway station and ambient samples in Seoul. According to their chemical composition, many distinctive particle types were identified. For samples collected at the subway station platform, the major chemical species are carbon-rich, organic, aluminosilicates (AlSi), AlSi/C, AlSi/$CaCO_{3},\;CaCO_{3},\;SiO_{2},\;and\;Fe_{2}O_{3}$. For outdoor samples, carbon-rich, organic, AlSi, $CaCO_{3},\;SiO_{2},\;NaNO_{3},\;(Na,Mg)NO_{3},\;Na(CO_{3},NO_{3},SO_{4}),\;and\;(NH_{4})_2SO_4$, are abundantly encountered. Samples collected at the subway station show very high contents of $Fe_{2}O_{3}$, both in coarse and fine fractions, which come from brake block, subway train wheel, electric contact materials, etc. It is demonstrated that the single-particle characterization using this low-Z particle EPMA technique provided detailed information on various types of chemical species in indoor and outdoor samples.

• Journal of the Korean Society for Railway
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• v.12 no.5
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• pp.631-640
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• 2009

In this paper, Numerical analysis was conducted to study on the reduction of ground vibration level induced by subway train. The analytical results indicated that the soil properties were the predominant factor affecting the ground vibration when the tunnel was located in the soil layer. On the other hand, the rock properties were the predominant one when the tunnel was located in the rock layer. The effects of the angle between the vertical line of vibration source and the receive point on the reduction of vibration level were also evaluated. There were little difference in the reduction of vibration level when the receive point was located within $30^{\circ}$. The vibration level, however, rapidly decreased when the angle between the two points was larger than $40^{\circ}$.

• Proceedings of the KSR Conference
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• 2008.11b
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• pp.509-517
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• 2008

Rolling stock is the method of railway transportation. Especially, in the subway system which has short headways particularly during the rush hours, even one train's trouble on the main line might influence the whole line. Accordingly, to prevent a train trouble on the main line, high expense is used for the maintenance parts, workforce and facilities, etc. according to the preventive maintenance program. Therefore, in designing a EMU, emphasis should be put on the minimization of trouble and its extending influence on the mainline with the priority of safety and reliability. Seoul subway line 5 is the line that complements the first stage Seoul subway(lines 1,2,3 and 4) and is built deeply with many curved sections causing lots of dust. Studies were made to find out the importance of car design, selection of specifications and continuous maintenance on the basis of the analysis and countermeasure of the line 5 EMU inverter trouble case.

• Journal of the Korean Society of Industry Convergence
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• v.26 no.2_2
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• pp.341-347
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• 2023

The subway is one of the most common and important means of transportation in modern society. In order to use the subway safely, tracks are necessary, but trains are prone to derailment and collisions. In order for the train to run safely on the track, the fishplate that connects the line connection is used. The damaged railway was a fishplate for connecting subway lines used for 11 years, and damage analysis and countermeasures were presented. Beach marks were observed on both fracture surfaces, and striations appeared at the range of crack propagation. The damaged part is Cr carbide, which has a higher hardness than the base metal, and is judged to be embrittled and destroyed by fatigue. The SM50C fishplate was subjected to a cyclic stress of about 59% of the upper limit of tensile-compression fatigue limit, but inclusions were the cause of failure. In order to prevent fatigue failure of the SM50C steel fishplate, the occurrence of inclusions should be minimized and processed to have a homogeneous structure when manufacturing the fishplate. In addition, compressive residual stress is given through surface modification such as peening to control crack generation. It is necessary to minimize the change in shape that can become a stress concentration part along with accurate fastening of the bolt, and to design the stress distribution to be as uniform as possible.

• Proceedings of the KSR Conference
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• 2005.11a
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• pp.953-957
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• 2005

Light Rail Transit(LRT) Systems with transport capacity between subway and bus(5,000-25,000 persons per hour) are being carried on over 100 lines around the world. In Korea, to solve the urban transportation problem, the introduction of LRT system has been proceeded positively. It is planned to develop the Korean standard LRT system in which safety, efficiency and cost effectiveness are emphasized. So we were able to make proto type of Rubber tired AGT system for LRT. This is capable of driverless operation using CBTC(Communication Based Train Control) of Moving Block System and is currently making an experiment for reliability in test-line. This study is focused on verifving the train tracking with CBTC in driverless and ATO mode through implementing the examination.

• Proceedings of the KIEE Conference
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• 2003.11c
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• pp.357-360
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• 2003

Improvement is required to solve problems depending on long term use of signal equipment in the existing city railroad and to raise quality of passenger services. Accordingly, for more efficient improvement, we examined the procedure of executing construction of the communication based train control system in Korean city railroads, which is globally studied. The procedure of executing construction of the system is to present a plan for construction first of ail and then to prepare a strategy for construction of the system. It is required to establish a procedure for execution in each step depending on the prepared strategy and then to establish a detailed execution plan. We studied such an execution procedure, divided the execution procedure for application of the train control system through five steps to prepare the execution procedure.

• Proceedings of the KIEE Conference
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• 2006.04a
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• pp.228-230
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• 2006

While trains perform a complete precision stopping control at stop point, it is essential to keep better commuters comfort in prompt. Because a train's brake force tends to increase a brake effort in a low speed and a low brake effort, a brake force in motor cars must be increased to keep better passenger comfort, to control the special braking qua1ities and to prevent the impact of the automatic coupler rather than trailer's, Rail cars must have a special braking process for the train stopping control. In the train stop mode, the train stopping control is designed to start at 20km/h. It starts by Dynamic brake blending, and then finally stops by only the friction. If these process are not exactly activated, the train may fail a complete precision stop. In this report, it studied the electric and friction brake processing during the precious stopping control. To achieve exact test results, the speed reference has to be reduced the calculated difference. In the precision stopping control. the ways of the keeping brake force in motor car was analyzed and some solutions of controling air pressure was brought up by means of direct test in main line, This study was based on line 5 in Seoul Metropolitan subway.

• The Journal of The Korea Institute of Intelligent Transport Systems
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• v.20 no.5
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• pp.1-17
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• 2021

Identifying the exact train and the type of train boarded by passengers is practically cumbersome. Previous studies identified the trains boarded by each passenger by matching the Automated Fare Collection (AFC) data and the train schedule diagram. However, this approach has been shown to be inefficient as the exact train boarded by a considerable number of passengers cannot be accurately determined. In this study, we demonstrate that the AFC data - diagram matching technique could not estimate 28% of the train type selected by passengers using the Seoul Metro line no.9. To obtain more accurate results, this paper developed a two-step method for estimating the train type boarded by passengers by applying the AFC data - diagram matching method followed by a mixture distribution analysis. As a result of the analysis, we derived reasonable express train use/non-use passenger classification points based on 298 origin-destination pairs that satisfied the verification criteria of this study.

• Proceedings of the KSR Conference
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• 2003.10c
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• pp.287-294
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• 2003

There are a lot of curved subway stations in Seoul metropolitan area. These must be straightly constructed as many as possible. But some of stations are roundly designed and built in order to avoid pre-existed underground obstacle such as basement of high rise building, underground gas or water pipe line and subway stations from another line. As shown fig 1, one of the biggest problem occurring curved subway station is considered large gap between platform and vehicle when vehicle completely stop at the station. The gap potentially is in existence to subway passenger as very dangerous factors in rush hours. If passenger accidentally drop their food or leg between this gap when they get on the train and train leaves station, the passenger will be seriously injured by vehicle. In this paper, various design and instruments are introduced and best solution for this matter will be presented. In order to eliminate any possibility of accident happened gap between platform and vehicle, KRRI(Korea Railroad Research Institute) have been developed new safety instrument. These technologies were applied for patent by KRRI. These mechanisms will provide confidence as well as safety to Korean subway passenger