• Journal of Energy Engineering
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• v.24 no.1
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• pp.17-23
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• 2015

Electrical door system is one of the most essential items for the successful commercial operation of the railway vehicles. Nowadays, reliability values of electrical door system have a tendency to be included in technical requirements for design and manufacturing of rolling stocks. Manufacturer shall meet the reliability target values of electrical door system which is proposed by railway operator in procurement contract book. Railway operator shall approve the supplier's the reliability target values based on maintenance operation data. Railway operators are in the transition stage from the framework of maintenance interval based on time to the framework of maintenance interval based on distance. In this study, failure rates of the electrical door system currently used in railway vehicles are collected from maintenance field data. Failure rates are analyzed by using Minitab. Several kinds of plan for improving reliability are also suggested. It is necessary to keep studying on reliability prediction methodology, applying it in the field and implementing on improvement of reliability through feedback as well. Further, it will be useful for determining new maintenance policies or changing maintenance intervals for existing railway vehicles.

• Proceedings of the KSR Conference
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• 2011.05a
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• pp.1556-1562
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• 2011

Recently many disadvantageous problems have been found during the process of domestic LRT(Light Rail Transit) projects and that can influence negative effects on the development of domestic railway. Since many projects have been progressed while having few original technologies, it is no exaggeration to say that they are being built unreasonable railway which lacks economic feasibility. The on-going LRT projects which are being carried out by the central or local government have a tendency to favor the systems and rolling stocks that have been approved by other countries through years of experience, therefore it can be said that we are having few chances to develop original technologies. In this study, we would like to promote railway development and jump up to the level of advanced railway standards through developing our unique and independent future LRT technology.

• Proceedings of the KSR Conference
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• 2011.05a
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• pp.1642-1646
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• 2011

One of the rolling stocks, low floor tram is recognized as the important alternative to improve traffic and environmental problems. There are many advantages of tram transportation system. It has, especially, low construction costs and easy accessibility. Trams operate with vehicles on roadways. The bogie configuration including traction motor of tramcar is different from that of conventional electric trains because tram has lower floor than train. In these reasons, the traction motors of tramcar are exposed to dusts, water and so on. Therefore, motors are designed by totally enclosed type. In this paper, we explain the design and test of totally enclosed traction motor for tramcar. Characteristic tests and temperature-rising tests were carried out in order to predict the performance of motor and the maximum temperature of coil.

• Proceedings of the KSR Conference
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• 2011.05a
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• pp.1604-1611
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• 2011

Light Rail Transit(LRT) is a large scale complex system which combines rolling stocks, power supply, signal communication, tracks & stations, and hundreds of billions of wons per project are spent for construction. Therefore efficient integration of sub-systems is very important. The systems engineering is a good method to reduce the cost and risk of LRT project. In this paper, we introduce a research plan on the application of systems engineering to LRT project. We, Korea Railroad Research Institute(KRRI), launched a research program with 4 companies, which is support by the governmen and project period is 4.5 years. Main research topic is to develop the technology for the application of systems engineering technical process to LRT project based on ISO/IEC 15288.

• Proceedings of the KSR Conference
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• 2011.10a
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• pp.498-508
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• 2011

First phase section of line 9 which had been constructed by first private capitalization business of Seoul city was opened on July 24, 2009. There are 25 stations of 25.5km operation distance between Gaehwa and Sinnonhyeon, running regular and express trains on the same track. The number of daily passenger demand has risen to above 200thousand passengers with record above 90% of anticipatied transport demand in 2010. The construction of second phase section(Sinnonhyeon~Bohoon Hospital : 14km, 13 stations) is currently under construction for opening in 2016. This study aims to suggest optimal operating patterns taking into consideration theoretical operating headways for regular and express trains, demand of rolling stocks mainly analyzed on record of first phase demand of line 9 and anticipated transport demand of second phase basic plan.

• Proceedings of the KSR Conference
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• 2011.10a
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• pp.931-938
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• 2011

Nondestructive inspection(NDI) is a testing procedure used to easily inspect an object for internal defects, abnormalities, shape, and structure, etc. without destroying it. Typical candidates for NDI include buildings, railways, aircraft, bridges, underground pipelines and various types of factory equipment. Recent advances in nondestructive evaluation(NDE) technologies have led to improved methods for quality control and in-service inspection, and the development of new options for material diagnostics. Under frame side sill in rolling stocks is designed for preventing corrosion in order to meet mechanical requirements. However during long operation time, there are corrosion in the under frame side sill caused by environmental effect, vibration and etc. This paper introduces the methods of a survey and assessment on NDI applications in Electric Multiple Units(EMU). The main objective of this paper was to obtain information on various applications and evaluation of NDI technology in EMU.

• Proceedings of the KSR Conference
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• 2011.10a
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• pp.1601-1606
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• 2011

The railway system consists of rolling stocks, facilities, electrical system, signaling and operation and so on, organically bound. Recently due to lots of train failures and accidents, especially the derailment related to track irregularity this year, all the people using the train are worried about railway safety and we paved the way for letting them knowing that all components of railway system are so important. As a result, most of developed countries operating railway have used to risk assessment methods about safety management to prevent railroad accidents in advance. The purpose of this paper is to find out how to closely apply to track field for risk assessment methods. Because there is no case to apply to and we're not interested in yet, despite of importance of track, in situations of higher train speed. Therefore, in this study we're going to investigate risk assessment methods and compare enire railway system with track system, eventually we want us try to present to safety management conditions necessary and secure safety improvement in track field.

• Proceedings of the KSR Conference
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• 2011.10a
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• pp.94-99
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• 2011

EMU(Electric Multiple Unit) of Seoul Metro are equipped with air conditioning and six line flow fans for air circulation. In summer, the air conditioning and line flow fans usually work at the same time. Recently, high oil price leads more people to use public transportation, which in turn makes them feel hotter inside the rolling stocks and complain about air conditioning state. In order to improve indoor air quality in summer, it is inevitable to increase the cooling capacity of air conditioners, which costs a lot of money. Thus, we need to raise cooling efficiency by rearranging existing devices effectively. In this study, we found a better way to improve refreshment inside the trains by changing the operation method of line flow fans and door opening systems. The results will help improve the cooling efficiency of EMU in summer. Also, more precise experiments and analyses of our data can lead to various methods to increase energy efficiency.

• Journal of the Korean Society of Safety
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• v.28 no.6
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• pp.79-83
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• 2013

The advent of private railroad corporations presented many problems on administration's effectiveness. These brought an effect on safety management too. Most public railroad corporations maintain their rolling stocks and facilities by their own workers. On the other hand, private railroad corporations depend on outsourcing to cut down the cost of maintenance. But they have similar safety management systems. Therefore we investigated the gap between the two types of corporations, focusing on workers' safety attitude and proposed solutions to improve safety management systems in private railroad corporations.

• Proceedings of the KIEE Conference
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• 2008.04c
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• pp.172-174
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• 2008

In the braking process of rolling stocks, the equivalent braking force is applied to the all bogies. However, the load applied to the front and rear bogie are different in the actual commercial traveling. In the case, since the different slip situation is occurred in each bogie, it is essential to use the independent anti-slip control per bogie unit in order to reduce the loss of braking force. In this paper, the mathematical modeling about bogie unit braking is proposed and verified.