• Title/Summary/Keyword: Railway Transportation

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The Analysis of Short Current on Actual System through Power Analysis of AT Feeder System for Electric Railway (전기철도 AT급전계통 전력해석을 통한 실계통의 단락전류 분석)

  • Jung, No-Geon;Jung, Ho-Sung;Koo, Kyung-Wan;Kim, Jae-Moon
    • The Transactions of The Korean Institute of Electrical Engineers
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    • v.63 no.11
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    • pp.1582-1587
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    • 2014
  • In this paper, we perform a modeling for the AT Feeder system in AC electric railway and we utilize the power EMTDC program to implement about AT feeder system modeling. In addition, we study the impedance characteristics of the AT feeder system and calculated fault current and impedance according to the distance due to fault accident. Based on it's result, fault current are compared between calculating the value and simulation value in EMTDC modeling. Impedance of power system is Largest at the middle point of the system and is smallest near autotransformer, and then showed that the fault current is inversely proportional to impedance characteristics.

An Application and Evaluation of Hub-and-spoke Strategy for Rail Freight Service in European Networks (철도화물서비스를 위한 Hub-and-spoke 운송전략의 적용과 평가: 유럽 사례를 중심으로)

  • 정승주
    • Journal of the Korean Society for Railway
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    • v.7 no.3
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    • pp.264-270
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    • 2004
  • The hub-and-spoke strategy is widely used in the field of transportation. At the field of rail transportation, however, it is difficult that we find an application case of this strategy because of modal characteristics. According to the fast growth of containerization and the development of transshipment technology, presently, the hub-and-spoke strategy is introduced by operators on actual European rail freight transportation. However, it is hardly to find empirical studies evaluating the applicability of transportation strategy. In this context, this study analyzed the applicabilities of hub-and-spoke strategy in the actual network of European rail freight. For the application and evaluation of the characteristics of hub-and-spoke strategy, it utilized a service network design model for rail freight. Utilizing this model, it analyzed the efficiency of furnished rail freight services, the potential locations of hubs, the characteristics of O-D flows by the types of trains and service links, and the types of paths of O-D flows. Finally, it proposed some implications and the further study topics.

The Comparison of Segmentation Performance between SegFormer and U-Net on Railway Components (SegFormer 및 U-Net의 철도 구성요소 객체 분할 성능 비교)

  • Jaehyun Lee;Changjoon Park;Namjung Kim;Junhwi Park;Jeonghwan Gwak
    • Proceedings of the Korean Society of Computer Information Conference
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    • 2024.01a
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    • pp.347-348
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    • 2024
  • 본 논문에서는 철도 구성요소 모니터링을 위한 효율적인 객체 분할 기법으로 사전학습된 SegFormer 모델의 적용을 제안하고, 객체 분할을 위해 보편적으로 사용되는 U-Net 모델과의 성능 비교 분석을 진행하였다. 철도의 주요 구성요소인 선로, 침목, 고정 장치, 배경을 분할할 수 있도록 라벨링된 데이터셋을 학습에 사용하였다. SegFormer 모델이 대조군인 U-Net보다 성능이 Jaccard Score 기준 5.29% 향상됨에 따라 Vision Transformer 기반의 모델이 기존 CNN 기반 모델의 이미지의 전역적인 문맥을 파악하기 상대적으로 어렵다는 한계를 극복하고, 철도 구성요소 객체 분할에 더욱 효율적인 모델임을 확인한다.

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Aerodynamic analysis on the step types of a railway tunnel with non-uniform cross-section

  • Li, Wenhui;Liu, Tanghong;Huo, Xiaoshuai;Guo, Zijian;Xia, Yutao
    • Wind and Structures
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    • v.35 no.4
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    • pp.269-285
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    • 2022
  • The pressure-mitigating effects of a high-speed train passing through a tunnel with a partially reduced cross-section are investigated via the numerical approach. A compressible, three-dimensional RNG k-ε turbulence model and a hybrid mesh strategy are adopted to reproduce that event, which is validated by the moving model test. Three step-like tunnel forms and two additional transitions at the tunnel junction are proposed and their aerodynamic performance is compared and scrutinized with a constant cross-sectional tunnel as the benchmark. The results show that the tunnel step is unrelated to the pressure mitigation effects since the case of a double-step tunnel has no advantage in comparison to a single-step tunnel, but the excavated volume is an essential matter. The pressure peaks are reduced at different levels along with the increase of the excavated earth volume and the peaks are either fitted with power or logarithmic function relationships. In addition, the Arc and Oblique-transitions have very limited gaps, and their pressure curves are identical to each other, whereas the Rec-transition leads to relatively lower pressure peaks in CPmax, CPmin, and ΔCP, with 5.2%, 4.0%, and 4.1% relieved compared with Oblique-transition. This study could provide guidance for the design of the novel railway tunnel.

A Strategy of Technology Development for the Railway System based on Railway Network (철도망 구축을 고려한 철도시스템의 기술개발전략)

  • Lee Hi-Sung
    • Journal of the Korean Society for Railway
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    • v.9 no.3 s.34
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    • pp.319-324
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    • 2006
  • Studied was a strategy of technology development for railway system in terms of railway network. First, The successful launch of the Korean HST system has not only decreased logistics burden but also significantly transformed the Korean trunk-line railway network, revolutionizing the logistics and technology sectors and reinvigorating the Korean railway industry in one century. Korean railway industry sector is now investing to develop many different types of railway system(G7, Post G7, tilting train...) so that these kinds of various railway system development should be integrated with the National Inter-modal Transportation Network Plan. To secure sufficient capacity that is required by the National Railroad Plan, the railway industry needs to establish mid- and long-term train purchase and operation strategies in compliance with railway construction and operation policies. During a railway construction planning, train operators, based on their train operation strategies, should come up with measures to closely cooperate with project operators from the planning stage through to the opening of a railway system. To be more precise, train operators should establish long-term train procurement plans reflecting both long-term national railroad network plans and plans for each railway line in order to suggest appropriate roles and schedules for each line. Also, based on the long-term railway plan, directions should be decided concerning the research and development of trains in advance.

Railway Governance and Power Structure in China

  • Lee, Jinjing
    • International Journal of Railway
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    • v.1 no.4
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    • pp.129-133
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    • 2008
  • Over the last $15{\sim}20$years, many countries have adopted policies of railway privatization to keep up with increasing competition from road and air transport. Although each country and case has its own history, market characteristics, political context as well as administrative process, railway privatizations (including railway restructure, concession etc.) in the west usually are accompanied with the establishment of new regulatory regimes. Therefore, railway governance has been innovating towards an interaction of government, regulator, industry bodies, user groups, trade unions and other interested groups within the regulatory framework. However, it is not the case in China. Although China had seen a partial privatization in some branch lines and is experiencing a much larger-scale privatization by establishing joint-ventures to build and operate high-speed passenger lines and implementing an asset-based securitization program, administrative control still occupies absolutely dominant position in the railway governance in China. Ministry of Railway (MOR) acts as the administrator, operator as well as regulator. There is no national policy that clearly positions railway in the transportation network and clarifies the role of government in railway development. There is also little participation from interested groups in the railway policy making, pricing, service standard or safety matter. Railway in China is solely governed by the mere executive agency. Efficiency-focused economic perspective explanation is far from satisfaction. A wider research perspective from political and social regime is of great potential to better explain and solve the problem. In the west, separation and constrains of power had long been established as a fundamental rule. In addition to internal separation of political power(legislation, execution and jurisdiction), rise of corporation in the 19th century and association revolution in the 20th century greatly fostered the growth of economic and social power. Therefore, political, social and economic organizations cooperate and compete with each other, which leads to a balanced and resonable power structure. While in China, political power, mainly party-controlled administrative power has been keeping a dominated position since the time of plan economy. Although the economic reform promoted the growth of economic power of enterprises, it is still not strong enough to compete with political power. Furthermore, under rigid political control, social organizations usually are affiliated to government, independent social power is still too weak to function. So, duo to the limited and slow reform in political and social regime in China, there is an unbalanced power structure within which political power is dominant, economic power expanding while social power still absent. Totally different power structure in China determines the fundamental institutional environment of her railway privatization and governance. It is expected that the exploration of who act behind railway governance and their acting strength (a power theory) will present us a better picture of railway governance as a relevant transportation mode. The paper first examines the railway governance in China and preliminarily establishes a linkage between railway governance and its fundamental institutional environment, i.e. power structure in a specific country. Secondly, the reason why there is no national policy in China is explored in the view of political power. In China, legislative power is more symbolic while party-controlled administrative power dominates political process and plays a fundamental role in Chinese railway governance. And then, in the part three railway finance reform is analyzed in the view of economic power, esp. the relationship of political power and economic power.

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A driving power supply unit design of the track special vehicle considering the urban railway underground environment (도시철도 지하환경을 고려한 궤도특수차의 주행동력장치 설계 검토)

  • Lee, Jae-Bong;Na, Youn-Il;No, Kyung-Won;Seo, lL-Kwon;Lee, Hwan;Kim, Yang-Soo
    • Proceedings of the KIEE Conference
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    • 2015.07a
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    • pp.1571-1572
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    • 2015
  • 기존 궤도특수차는 디젤유를 사용하기 때문에 도시철도 지하환경을 오염시키고 유해한 배기가스가 인체에 악영향을 준다. 따라서 경제성이 우수한 친환경적인 하이브리드형 궤도특수차를 개발하기 위해 이에 따른 궤도특수차의 주행동력장치에 대한 설계조건을 규명하고자 한다.

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A study on the trend of the rail transportation in view of the change of Korea public transportation (국내 육상교통 수단의 변천과정에서 본 철도고통의 발전방향)

  • 최출헌;한석윤;정종덕
    • Proceedings of the KSR Conference
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    • 2002.05a
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    • pp.94-99
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    • 2002
  • The traffic policy of a city in Korea has brought to many traffic problems by putting emphasis on the only side of mobility in the past that the personal transportation was put first in importance more than the public transportation. As the result of this policy, in the process that the traffic policy of large cities in Korea changes into accessibility, it is shown for re-lighting up the development of the public transportation to be going to be able to get many suggestions in searching for the desirable developing direction of the new means of transportation that will arrive at Korea in the future. Especially, compared with the policy of U.S.A. on the traffic plan that has concentrated on the road and the vehicle, and that of Europe that has put first in the walking and the public transportation system, it is considered as an important thing that the lesson is given to us about what is important for the desirable city development. Transportation can be divided into four; a railroad transportation. a road transportation, a marine transportation, and an aerial transportation.

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Analysis of bulk freight transportation (벌크화물 수송실태 분석)

  • Lee, Suk;Kim, Young-Joo;Kim, Kyoung-Tae;Kwon, Yong-Jang;Kim, Seung-Mo
    • Proceedings of the KSR Conference
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    • 2011.10a
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    • pp.3278-3288
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    • 2011
  • Bulk freight is transported by a freight car, ship and tank lorry without packaging in a state of particles or powders. In korea, the main bulk freight include oil, grain, coal, cement, iron ore and these are occupied nearly 30% of the volume of gross domestic freight transportation. Therefore it is in important to transport efficient bulk freight transport system for the improvement of national distribution competitive as raw material for industry. Generally environment-friendly transfer modes such as railway and sea transport play an important role in bulk freight transport due to the mass transfer characteristics of bulk freight. This study is carried out for examining the problem of oil, grain, coal, cement, ore transportation through analyzing distribution flow of items and understanding characters of transfer modes.

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Improvement of Overspeed Protection for Automatic Train Stop System (열차자동정지시스템(ATS)의 과속방지장치 개발)

  • Jeong, Rag-Gyo;Kim, Baek-Hyun;Kang, Seok-Won;Seo, Moon-Seog
    • The Transactions of The Korean Institute of Electrical Engineers
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    • v.67 no.1
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    • pp.61-67
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    • 2018
  • Automatic Train Stop (ATS) is a device that automatically stops or decelerates a train when the train exceeds the permitted speed limits or violates the signal regulations. The railway signaling system has been evolved to an automatic train control system (ATC), and is being developed into Distance-to-Go and Communication Based on Train Control (CBTC). In spite of that, the ATS system is currently being operated in Seoul Metro (line 1 and 2) and most of railway lines in Korea as well as overseas. In this study, we presents the technical methodology to prevent human errors in order to secure the safety in operation of the ATS system.