• 제목/요약/키워드: Railways

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Instantaneous Environmental Noise Simulation of High-speed Train by Quasi-stationary Analysis (준정적 해석을 이용한 고속 열차의 순간 환경소음 시뮬레이션)

  • Cho, Dae-Seung;Kim, Jin-Hyeong;Choi, Sung-Won;Chung, Hong-Gu;Sung, Hye-Min;Jang, Seung-Ho;Koh, Hyo-In
    • Transactions of the Korean Society for Noise and Vibration Engineering
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    • v.22 no.10
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    • pp.1003-1009
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    • 2012
  • An instantaneous environmental noise simulation method emitted by a moving high-speed train by quasi-stationary analysis is proposed in this study. In the method, the propagation attenuations from stationary point sources on segmented railways to a receiver are calculated using a general purpose environmental noise prediction program ENPro based on the ISO 9613-2 method. Then, the instantaneous environmental noise at a receiver due to a moving high-speed train considering convection effect is evaluated with the information on the propagation attenuations from the instantaneous train location to the receiver and the sound power levels and directivity of stationary point sources evaluated by German Schall 03 (2006). To demonstrate the validity of proposed method, simulated and measured time history of instantaneous noise for KTX-I and KTX-II on running are compared and the results show that the method can be utilized for the train noise source identification as well as the simulation of instantaneous environmental noise emitted by a high-speed train.

Influence of Vehicle Vibration on Track Geometry Measurement (차량 진동이 궤도 선형 측정에 미치는 영향)

  • Bae, Kyu-Young;Yong, Jae Chul;Kim, Lee-Hyeon;Kwon, Sam-Young
    • Transactions of the Korean Society for Noise and Vibration Engineering
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    • v.26 no.6_spc
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    • pp.644-650
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    • 2016
  • Track maintenance works based on track geometry recordings are essential to enhance the safety and comfort of railway transportation. Usually, the track irregularity has been measured by a special inspection trains which all were imported from abroad. Because the inspection train speed is limited under 160 km/h, it takes a long time to inspect railways and there is difficulty in daytime operation. To solve this problem, we started to develop a track geometry measuring system (TGMS) with measurement speed up to 300 km/h which can be installed in commercial vehicles such as HEMU-430X. In this paper, we introduce a newly developed inertial TGMS and propose two inertial navigation system (INS) algorithms (method A, B) for measuring track geometry. In order to investigate advantage and disadvantage of each algorithm, we performed vibration test of the TGMS, which was simulated by 6-axis shaking table. Through the vibration test, we analyzed the influence of vehicle vibration on the TGMS which will be installed on bogie frame. To the vibration test, two methods satisfied the required accuracy of track geometry measurement under the level of the actual vehicle vibration of HEMU-430X train. Theoretically, method A is sensitive to vehicle vibration than method B. However, HEMU-430X's bogie vibration frequency range is out of interest range of measurement system. Therefore, method A can also apply the HEMU-430X train.

Evaluation of Track Irregularity Effect due to Adjacent Excavation on Serviced Railway Line (철도시설물 인접굴착공사에 따른 운행선 궤도의 궤도틀림 영향 평가)

  • Choi, Jung-Youl;Park, Dong-Ryong;Chung, Jee-Seung
    • The Journal of the Convergence on Culture Technology
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    • v.5 no.4
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    • pp.401-406
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    • 2019
  • The three-dimensional precision numerical analysis was performed using the finite element model applied with the railway track model consisting of rails, sleepers, and track elastic springs(ballast, rail pad). As a result of analyzing the track deformation level of the existing tracks due to the excavation work adjacent to the railway facilities, it was found that the track irregularity evaluation criteria (allowed values) of both conventional and high-speed railways lines were satisfied. Based on the numerical analysis using the track model, it was analyzed that the results of the prediction of the track irregularity due to the excavation work and the level of the track deformation occurring at the actual site could be approximated as closely as possible.

Numerical modeling of two parallel tunnels interaction using three-dimensional Finite Elements Method

  • Nawel, Bousbia;Salah, Messast
    • Geomechanics and Engineering
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    • v.9 no.6
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    • pp.775-791
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    • 2015
  • Due to the extension of communication ways (metro, highways, railways), hence, to improve traffic flow imposes often the difficult crossing that generally drive to the construction of underground works (tunnel, water conveyance tunnel...) plays a major role in the redevelopment of urban areas. This study is focused on the assessment of the interaction response of parallel tunnels, so this study uses the results from the simulation of two tunnels to illustrate a few observations that may aid in practical designs. In this article, simultaneous drilling of highway's twin tunnels is simulated by means of Finite Element Method (FEM) implemented in Plaxis program. So the treated subject appears in a setting of geotechnical where one can be to construct several tunnels sometimes in a ground of weak mechanical characteristics. The objective of this study is to simulate numerically the interaction effects caused by construction of two parallels tunnels. This is an important factor in the study of the total answer of the problem interaction between parallels underground works. The importance of the effects transmitted is function of several parameters as the type of the works, and the mechanical characteristics (tunnel size, depth, and the relative position between two tunnels, lining thickness...). This article describes numerical analyses of two parallels tunnels interaction. This study will be applied to a real case of a section tunnel T4 of the highway East-West (Algeria); the study presented below comprises a series of numerical simulations of two tunnels using the computer program Plaxis which is used in the analyses is based on Finite Element Method.

Development of Catenary Stagger and Height Measurement System using Laser (레이저를 이용한 전차선 편위 및 높이 측정 시스템 개발)

  • Song, Sung-Gun;Lee, Teak-Hee;Song, Jae-Yeol;Park, Seong-Mo
    • Journal of the Korean Society for Railway
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    • v.11 no.6
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    • pp.569-574
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    • 2008
  • Catenary and Pantograph are used to transmit electrical energy to electric railways. Catenary (Overhead Contact Lines) should be installed precisely and managed for stable train operations. But external factors such as weather, temperature, etc., or aging affect catenary geometry. Changed catenary stagger and height cause high voltage spark or instant electric contact loss. Big spark derived from contact loss can damage the pantograph carbon strip and overhead contact lines that might interrupt the train operations. Therefore, to prevent a big scale spark or electric contact loss, catenary maintenance are required catenary geometry measurement systems with catenary maintenance capability. In this paper, we describe the development of catenary height and stagger measurement system. The catenary height and stagger measurement system uses Acuity company's AR4000 Laser Range Finder for distance measurement and AccuRange Line Scanner for degree measurement. This system detects suspicious overhead line sections with excessive stagger and height stagger variance.

Method for Calculating the Line Capacity Using Computer Aided Simulation (시뮬레이션 기법에 의한 선로용량 산정방법)

  • Choi, Jong-Bin;Lee, Jinsun;Ki, Hyung-Seo
    • Journal of the Korean Society for Railway
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    • v.19 no.4
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    • pp.555-563
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    • 2016
  • Line capacity of railways is a core criterion to decide maximum trips in accordance with traffic demand and a priority in railway investment to improve transportation capability. Particularly, because two operators will start revenue services in the HSR from mid-2016, the line capacity should be carefully calculated and controlled to avoid conflicts between the maximum number of KTXs, and the number needed to guarantee the effective competition of the operators. Meanwhile, there have been many arguments about calculating the line capacity, because this number is affected by the number of trips by train types, stopping pattern and dwell time in each station, journey time, crossing or passing, safety headway between trains, etc. To deal successfully with these kinds of problems, this study proposes a simulation method to calculate the line capacity that considers train operation according to the operator's service policies.

Study on the Rolling Noise Model Using an Analysis of Wheel and Rail Vibration Characteristics (철도 차륜 및 레일 진동 특성 해석을 통한 전동 소음 모델 연구)

  • Jang, Seungho;Ryue, Jungsoo
    • Journal of the Korean Society for Railway
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    • v.16 no.3
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    • pp.175-182
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    • 2013
  • Rolling noise is an important source of noise from railways; it is caused by wheel and rail vibrations induced by acoustic roughness at the wheel/rail contact. To reduce rolling noise, it is necessary to have a reliable prediction model that can be used to investigate the effects of various parameters related to the rolling noise. This paper deals with modeling rolling noise from wheel and rail vibrations. In this study, the track is modeled as a discretely supported beam by regarding concrete slab tracks, and the wheel vibration is simulated by using the finite element method. The vertical and lateral wheel/rail contact forces are modeled using the linearized Hertzian contact theory, and then the vibration responses of the wheel and rail are calculated to predict the radiated noise. To validate the proposed model, a field measurement was carried out for a test vehicle. It was found that the predicted result agrees well with the measured one, showing similar behavior in the frequency range between 200 and 4000 Hz where the rolling noise is prominent.

A Study on the Establishment of Redundancy for Stable Operation of Integrated Railway Network (LTE-R) (철도통합무선망(LTE-R)의 안정적인 운영을 위한 이중화 구축 방안 연구)

  • Pyo, Seung-ho
    • Journal of the Korea Academia-Industrial cooperation Society
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    • v.20 no.2
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    • pp.51-58
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    • 2019
  • The LTE system decided to build an integrated disaster safety communication network in order to cope with disasters quickly after the April 16, 2014 disaster, and 333 agencies in 8 areas will build a unified disaster safety communication network. It plans to integrate LTE-R, a railway integrated wireless network, and LTE-M, a land-based communication network, in the 700MHz band. LTE-R, a wireless integrated network, and the Ministry of Land, Transport and Maritime Affairs, are currently using VHF and TRS, which are voice communication-oriented communication systems, in order to cope with demand for high-speed railway service, With this possible LTE-R, it is possible to provide advanced services such as radio-based train control and improve railway safety. The company plans to invest KRW 1.1 trillion in new routes to be launched in 2018 and the existing route to be improved in the future, and to build up all routes of general and high-speed railways to LTE-R by 2027.

A Study on Interoperability for North-South Korean Railway Direct Connection (남북철도 직결운행을 위한 상호운용성 고찰)

  • Park, Eun-Kyung
    • The Journal of the Korea institute of electronic communication sciences
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    • v.13 no.6
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    • pp.1161-1168
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    • 2018
  • On April 27 2018, North-South Korea agreed to establish the practical methods for connecting the railway in the inter-Korean summit talks. This is often reported that the train will be operated directly between Busan and Europe. However, there are many problems for the railway to directly connect between Busan and Europe. Because a train from Busan to Europe should pass through North Korea, China or Russia, and each national railway systems are different. Thus, South Korean railway has to study thoroughly an interoperability before railways directly operates between a nation and another. The standards and technical harmony for direct connection with a different railway network is very important, because a rail transport is a total network system. This paper surveyed a European railway interoperability and studied on the basic direct operation for the North-South Korean railway systems.

Investigation of Pollution of Polycyclic Aromatic Hydrocarbons and Heavy Metals in Soil near Railway Rails (철도레일 부근 토양의 다환방향족 탄화수소 및 중금속 오염도 조사)

  • Choi, Hyun-Kyung;Yoon, In-Ju;Shin, Tae-Cheon;Kim, Young-Hun
    • Journal of Environmental Science International
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    • v.27 no.11
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    • pp.947-956
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    • 2018
  • Trains have been a major means of transport in Korea during these past decades. However, train facilities such as stations and repair shops are contaminated with organic and inorganic substances. There is a high probability of train facility contamination with polyaromatic hydrocarbons (PAHs). This study evaluated the PAH and heavy metal contamination of soil near railroads in the Kyungpook area. A total of 18 soil samples were collected from the railroads and analyzed for 16 PAHs and 6 heavy metal species. The contamination level of the top soil was found to be slightly higher than that of the subsoil for contamination with PAHs. The ratio of carcinogenic PAH concentration to the total PAH concentration was relatively high, with a maximum of 0.9. The toxicity equivalent (TEQ) of the PAHs were 500.6 ng/kg in the topsoil and 355.5 ng/kg in the subsoil. The ratio of low molecular PAHs (LPAHs) to high molecular PAHs (LPAHs) ranged from 6.7 to 29.5; this shows that contamination is primarily due to combustion of fuel rather than due to petroleum. The ratio of phenanthrene to anthracene and the ratio of fluoranthene to pyrene also show that contamination occurred due to combustion for transportation. The heavy metal contamination level was lower than the Korean standard, but higher than the background concentration; this indicates that the soil was affected by the operation of the railways.