• Proceedings of the Korean Geotechical Society Conference
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• 2003.06a
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• pp.103-116
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• 2003

Rockfall Protection fence is one of the most common rockfall Protection methods in Korea. If rockfall protection fences are required along the road or railway, their location, height and capacity, in terms of the maximum kinetic energy that they can absorb, should be specified. Within this paper, the best practice of rockfall barrier is introduced. Modern rockfall simulations as a means to define risks, protection requirements, dynamic loading and height of potential structures and selection of appropriate placement is presented. Technical possibilities of rockfall barriers and their actual limits are presented. Safety concepts based on probabilistic approaches are proposed. Recent studies peformed in other countries show that Flexible Barriers are also a feasible system to stop and retain debris flows. Finally an outlook onto further development is given.

• Proceedings of the KSR Conference
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• 2011.05a
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• pp.652-659
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• 2011

Due to overuse of commercial network systems such as bluetooth and WI-FI, the problems of frequency interruption and line-crossing may arise. For this reason, wireless communication frequency ISM 2.4GHz, a recently adapted concept in Korea which is employeed by RF-CBTC system, is predicted not to have guarantee for outstanding and continuous performance. Therefore in this study, considering these problems, 5GHz capacity wireless Lans with international standard 802.11a/b/g applied were installed in the underground urban transit areas and it was proved that these lans exceeded the performance level of 2.4GHz with international standard 802.11b which is being introduced in the nation. In addition, it was verified through carrying out an application test that the communication condition was stable in a running train with high speed in the tunnel.

• Proceedings of the KSR Conference
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• 2011.05a
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• pp.1364-1371
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• 2011

Advanced EMU completed a production of test train, composed of 6 cars, after 5 years of development process, and it is currently under the process of integrated test and evaluation to inspect performance of car system, efficiency of transport, safety, punctuality, energy efficiency in accordance with urban railways act at Daebul test line. Advanced EMU was produced under consideration of transportation capacity, maintainability, reliability, energy saving, convenience of passengers, and traffic-vulnerables, so it has an epochal difference from former EMU system. And advanced EMU assures operation management from manager's perspective and efficiency of maintenance for practicalization of car and individual equipment. This paper introduces each major equipment of advanced EMU which is based on many years of experience of management and maintenance.

• Proceedings of the KSR Conference
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• 2011.10a
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• pp.2594-2599
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• 2011

In Korea, the HEMU-400X(High-speed Electric Multiple Unit-400km/h eXpress) has been developed since 2007 and will be operated over 400km/h in 2013. It is necessary to prepare test-bed section in Honam high-speed railroad to take the maxim running speed test for the HEMU-400X developed. In order to determine proper test-bed sections for the maximum speed of 400km/h, TPS(Train Performance Simulation) program with the data of train model, running resistance, traction power and braking capacity was used to analyze the train performances such as locations, speeds and power consumptions by times. In this study, the specifications of the HEMU-400X project and the route conditions of the Honam high-speed railroad under construction were utilized for the TPS program to determine the optimal test-bed sections for the maximum speed of 400km/h.

• Proceedings of the KSR Conference
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• 2011.10a
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• pp.490-497
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• 2011

When operating Express and Standard trains, which run with two different scheduled time, in a single line with limited number of side tracks for overtaking standard trains, it is required to have various modeling methodologies and simulations in order to calculate an optimum headway to maximize the capacity of the line with the best scheduled time. Especially it is inevitable that following trains have to slow down or stop in the middle of their operations due to the preceding trains, in case it is inappropriate controlled about either in which station an overtaking should be taken or how long it should be. This study is to analyze TPS data which have been produced with a simulation program which the team has invented to optimize Express and Standard mixed traffic plan and to introduce an algorism which shows detected conflict data, calculates appropriate dwell time after getting overtaken and helps to decide stations for overtaking.

• Proceedings of the KSR Conference
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• 2011.10a
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• pp.2153-2162
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• 2011

The goal of this Paper is to reduce rail's wear in curved track by applying an additional surface layer material(High hardness and High resistance capacity of wear) on the top of the railhead. In order to evaluate appropriation of a coating material, experimental tests such as the varieties of fundamental properties tests (hardening, wear, tensile, and bending) and RCF(rolling contact fatigue)test were performed to establish fatigue wear and damage mechanism. As a result, wear performance of coating rail is better than heated rail about 6times and normal rail about 8~9times.

• 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.

• Proceedings of the KSR Conference
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• 2011.10a
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• pp.1997-2004
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• 2011

The $2{\times}25kv$ AT electric power feeding method in the A.C. electric train adopts the one-phase power feeding method as the standard due to a voltage phase difference, and the distance between the two neighboring substations is 50km due to voltage drop. The one-phase power feeding method makes the system operation feasible, while making it unfavorable for power supply. Moreover, railroad involves large-capacity single-phase load, and if it is expected to continue to rise, it is necessary to research on measures to stabilize the supply of power to railroad cars with the existing facilities. In this study, a parallel power feeding method between neighboring substations is proposed to stabilize the supply of electric power to electric railroad cars under the 2*25kv AT power feeding method and the loop current induced by voltage phase difference between the two neighboring substations during parallel power feeding is investigated.

• Proceedings of the KSR Conference
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• 2011.10a
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• pp.994-999
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• 2011

The main wearing slider of pantograph is a difference which is considerable to wear phenomenon according to material properties. Especially, Cu-type wearing slider suddenly occurs the abnormal wear by precipitation, this threatens the travelling safety of the train. The abnormal wear by precipitation and arc influences are main factor decided to life time of Cu-type wearing slider and contact wire. Consequently, the application of the main wearing slider with wear resisting capacity, electrical conductivity, resistance arc and lubrication is demanded. In this paper through tribologic approach, overcame abnormal phenomenon of the Cu-type wearing slider by the precipitation and for the economic efficient augmentation by durability improvement and the travelling safety were accomplished. The Cu-type wearing slider which has excellent electric conductivity and arc characteristic but it occurs the normal and abnormal wear phenomenon according the precipitation which changes, respectively. Consequently, this phenomenon grasps fixed quantity according to precipitation, a mileage and wear volume then Fe-type wearing slider compared and analyzed.

• 제어로봇시스템학회:학술대회논문집
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• 2003.10a
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• pp.1720-1723
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• 2003

Recently, as the road capacity reaches a limit and environmental problems becomes serious, there exists a gradually increased need for railway vehicles that are environment-friendly, punctual, reliable and safe. Accordingly, in addition to conventional railroad vehicles, lots of vehicles are being newly developed. Korean High Speed Train has been developed for last 6 years to satisfy the need. Authors developed a measurement system for on-line test and evaluation of performances of Korean High-Speed Train. The measurement system is composed of software part and hardware part. Perfect interface between multi-users is possible. A new method to measure temperature was applied to the measurement system. By using the system, measurement and evaluation of the mechanical characteristics of motors and main transformers in Korean High Speed Train was conducted during test running. The measured results for the temperature characteristics of electric devices verify that the measurement system is accurate and reliable.