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REFERENCE LINKING PLATFORM OF KOREA S&T JOURNALS
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Journal of the Korean society for railway
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Journal DOI :
Korean Society for Railway
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Volume & Issues
Volume 19, Issue 4 - Aug 2016
Volume 19, Issue 3 - Jun 2016
Volume 19, Issue 2 - Apr 2016
Volume 19, Issue 1 - Feb 2016
Selecting the target year
Noise Contribution Analysis of Pantograph Using Real Train Experiment
Oh, Hyuck Keun ; Noh, Hee-Min ; Kim, Jun-Kon ; Park, Choonsoo ;
Journal of the Korean society for railway, volume 19, issue 3, 2016, Pages 271~279
DOI : 10.7782/JKSR.2016.19.3.271
Pantograph aerodynamic noise is a major cause of noise that occurs when a train is traveling at high speeds. In this study, in order to analyze the contribution of pantograph aerodynamic noise, real train tests using HEMU-430X were carried out. In order to analyze the frequency characteristic of the noise of the pantograph in an actual vehicle, a sound field visualization has been carried out using a 144-channel microphone array at train speeds of 350 and 400km/h. As a result, it was confirmed that the low frequency noise in the 250~400Hz bandwidth provides the main contribution to the pantograph noise. And, in order to estimate the noise contribution of the pantograph, the noise level difference between cases in which the pantograph is ascending and those in which it is descending were compared in single microphone experiments. The frequency analysis in the single microphone tests showed that the bands of 315~400Hz and 1000~1250Hz are the main frequency characteristics of pantograph noise. These results show quite good agreement with those of previous studies and with results of sound field visualization.
Diurnal Variation of the Dust Concentration in a Railway Tunnel
Woo, Sang Hee ; Kim, Jong Bum ; Hwang, Moon Se ; Tahk, Gil-Hyun ; Yoon, Hwa Hyeon ; Yook, Se-Jin ; Bae, Gwi-Nam ;
Journal of the Korean society for railway, volume 19, issue 3, 2016, Pages 280~287
DOI : 10.7782/JKSR.2016.19.3.280
In railway tunnels, dust is generated when trains run due to the contact between the wheels and the rails. The generated dust is suspended due to the train-induced airflow, with some of it deposited due to gravitational sedimentation. In this study, the diurnal variation of the dust concentration was investigated in a railway tunnel. A single lane of a tunnel was selected in which to observe more easily the dust concentration due to the passing of a train. Four particle-measuring instruments were utilized to detect dust ranging from 5nm to
. To synchronize the train passing time at the measuring location, a three-dimensional ultrasonic anemometer and a video camera were used. It was found that the dust concentration was significantly increased from
due to the train. Particularly, the dust concentration was greatly increased to more than
during the morning rush-hour times.
Simulation and Testing of the Effect of Current Collection Performance According to Pre-sag in 400km/h Overhead Contact Lines
Kwon, Sam Young ; Cho, Yong Hyeon ; Lee, Kiwon ; Oh, Hyuck Keun ;
Journal of the Korean society for railway, volume 19, issue 3, 2016, Pages 288~296
DOI : 10.7782/JKSR.2016.19.3.288
A 400km/h simple catenary system was constructed as a test line in Korea. In the design stage of this system, the pre-sag was one of the engineering issues most focused on. It is known that the pre-sag improves the current collection performance in a certain band of high speed. However, the effect of pre-sag at 400km/h has not yet been established. To grasp a better pre-sag in the 400km/h catenary, we transacted the dynamic performance prediction simulation between catenary and pantograph under conditions of 0 and 1/3000 pre-sag. The level of 0 pre-sag was adapted for the 400km/h catenary design after reviewing predictions. We constituted the 1/3000 pre-sag sample section (about 1km) while constructing the 400km/h catenary test-bed (28km) of 0 pre-sag. With a HEMU-430X train, the contact forces were measured in the test-bed including the pre-sag sample section. In this paper, the predicted and measured dynamic performance values (contact forces) for 0 and 1/3000 pre-sag are described and compared. It is conclusively confirmed by analytical and experimental examination that the non pre-sag showed better dynamic (current collection) performance than that of the 1/3000 pre-sag for the 400km/h catenary system.
Research on High-Efficiency Power Conversion Structure for Railroad Auxiliary Power Supply(APS) System
Cho, In-Ho ; Jung, Shin-Myung ; Lee, Byoung-Hee ;
Journal of the Korean society for railway, volume 19, issue 3, 2016, Pages 297~303
DOI : 10.7782/JKSR.2016.19.3.297
This paper introduces auxiliary power supply systems (APS) for railroad applications and proposes a new power conversion structure for highly-efficient and lightweight APS systems. The proposed structure focuses on an improvement of the power density in APS. It eliminates unnecessary power conversion stages in the conventional APS structure by modulating the dc/dc converter circuit and the structure of the system. The dc/dc converter circuit used in the proposed structure is based on a multi-level half-bridge converter, a widely used topology in railroad APS applications; a flying capacitor is newly added to the conventional circuit. The added capacitor is used not only to enhance the soft switching condition of the switches, but also so that the new pantograph will have a side voltage source of a battery charger in the APS structure. Since the battery charger uses the pantograph side voltage source in the proposed structure, rather than using the output of the main dc/dc converter in the conventional structure, the size and efficiency of the main dc/dc converter are reduced and increased, respectively. To verify the effectiveness of the proposed structure, simulation results will be presented with metropolitan transit APS specifications.
Performance Assessment of High-Speed Transponder System for Rail Transport on High-Speed Line
Park, Sungsoo ; Lee, Jae-Ho ; Kim, Seong Jin ;
Journal of the Korean society for railway, volume 19, issue 3, 2016, Pages 304~313
DOI : 10.7782/JKSR.2016.19.3.304
It is necessary to receive telegrams transmitted by transponder tags installed along the track in order to detect the exact position of a high-speed train. In a high-speed railway environment, telegrams can be corrupted by the electromagnetic interference that comes from onboard electric train power equipment or wayside devices. In this study, we verified the railway environment compatibility of a high-speed transponder system developed as a train position detection system. We installed transponder tags on the Honam high-speed line and measured the number of error-free telegrams received from the transponder tag while the HEMU-430X was running at 268km/h~334km/h. Based on the measurement, we estimated the length of the contact zone formed between the transponder reader and tag. Field test results allow us to estimate how many error-free telegrams can be received when HEMU-430X is at speeds up to 400km/h.
RC Circuit Parameter Estimation for DC Electric Traction Substation Using Linear Artificial Neural Network Scheme
Bae, Chang Han ; Kim, Young Guk ; Park, Chan Kyoung ; Kim, Yong Ki ; Han, Moon Seob ;
Journal of the Korean society for railway, volume 19, issue 3, 2016, Pages 314~323
DOI : 10.7782/JKSR.2016.19.3.314
Overhead line voltage of DC railway traction substations has rising or falling characteristics depending on the acceleration and regenerative braking of the subway train loads. The suppression of this irregular fluctuation of the line voltage gives rise to improved energy efficiency of both the railway substation and the trains. This paper presents parameter estimation schemes using the RC circuit model for an overhead line voltage at a 1500V DC electric railway traction substation. A linear artificial neural network with a back-propagation learning algorithm was trained using the measurement data for an overhead line voltage and four feeder currents. The least square estimation method was configured to implement batch processing of these measurement data. These estimation results have been presented and performance analysis has been achieved through raw data simulation.
Investigation of Electromagnetic Force for Magnetic Contactor of Railway Vehicles
Jung, Jooyoung ; Park, Ji-Won ; Choi, Jinnil ;
Journal of the Korean society for railway, volume 19, issue 3, 2016, Pages 324~330
DOI : 10.7782/JKSR.2016.19.3.324
A magnetic contactor is a switching device widely used for electric circuits. For the operation of magnetic contactors, magnetic coils are essential; these coils create and interrupt the electric circuit. In this paper, the finite element analysis model was developed to reflect the experimental data, and was verified through alteration of the applied voltages and the numbers of turns. Effects of electromagnetic force on the geometrical variations of the facing poles for fixed and moving cores of two magnet coils were investigated. In addition, effects of slope and air gap size between two facing poles on the electromagnetic force were explored through the distribution of the magnetic flux density in the magnetic coils of a push-type solenoid. Through this analysis, the characteristics of the electromagnetic force against the facing poles were explored.
Design Graphs for Asphalt Concrete Track with Wide Sleepers Using Performance Parameters
Lee, SeongHyeok ; Lim, Yujin ; Song, Geunwoo ; Cho, Hojin ;
Journal of the Korean society for railway, volume 19, issue 3, 2016, Pages 331~340
DOI : 10.7782/JKSR.2016.19.3.331
Wheel load, design velocity, traffic amount (MGT), stiffness and thickness of sub-layers of asphalt concrete track are selected as performance design parameters in this study. A pseudo-static wheel load computed considering the dynamic amplification factor (DAF) based on the design velocity of the KTX was applied to the top of asphalt concrete track for full three dimensional structural analysis using the ABAQUS program. Tensile strains at the bottom of the asphalt concrete layer and vertical strains at the top of the subgrade were computed from the structural FEA with different combinations of performance parameter values for one asphalt concrete track section. Utilizing the computed structural analysis results such as the tensile strains and the vertical strains, it was possible to develop design graphs to investigate proper track sections for different combination of the performance parameters including wheel load, design velocity, traffic amount(MGT), stiffness and thickness of asphalt concrete layers for any given design life. By analyzing the proposed design graphs for asphalt concrete track, it was possible to propose simple design tables that can be used by engineers for the effective and fast design of track.
Analysis of Shear Behavior of Shear Key for Concrete Track on Railway Bridge Considering Construction Joint
Lee, Seong-Cheol ; Kang, Yun-Suk ; Jang, Seung Yup ;
Journal of the Korean society for railway, volume 19, issue 3, 2016, Pages 341~350
DOI : 10.7782/JKSR.2016.19.3.341
Concrete track on railway bridges should be designed to effectively respond to the movement of the superstructure of the bridge. In the design procedure, shear keys are generally placed on the protection concrete layer (PCL) before casting the concrete track so the shear force due to slip between the concrete track and the bridge super-structure can be transferred. In this paper, a nonlinear structural analysis procedure that considers the construction joint has been developed to predict the shear behavior of a shear key. With the developed analysis procedure, it was possible to predict the shear force-shear slip response at the construction joint in a shear key by considering the friction of concrete surface and the dowel action of the rebars. The analysis results showed good agreement with the test results for 4 specimens.
The Effect of High-speed Railway Station Facilities and Train Related Services on Customer Satisfaction: Based on KTX User Experience
Lee, Kang-duck ; Hwang, Eun-Ju ; Yeom, Sun-Ho ; Kim, Min-Ho ; Jo, Hye-Jung ;
Journal of the Korean society for railway, volume 19, issue 3, 2016, Pages 351~362
DOI : 10.7782/JKSR.2016.19.3.351
The purpose of this study is to investigate service factors and relationships affecting customer satisfaction by measuring indexes of the entire set of high-speed railway station facilities and train services. In this study, we collected data from 202 KTX passengers and analyzed the data using the structural equation model (SEM) method. Through exploratory factor analysis (EFA), we found five major service factors, including parking related service (PRS), station convenient facilities related service (SCS), ticketing services (TIS), service within the train (SWT), and inner environments (INE). As result of a hypothesis test, it was found that PRS does not influence SWT, whereas SCS and TIS positively affect train related service. Also, SWT and INE significantly affect the overall service satisfaction of customers. Thus, our findings provide that station facilities and train service experience are important factors that can enhance customer satisfaction.
Analysis of Influence Factors and Current Conditions for Korean Railway Export
Mun, Jinsu ;
Journal of the Korean society for railway, volume 19, issue 3, 2016, Pages 363~372
DOI : 10.7782/JKSR.2016.19.3.363
This study identifies influence factors for Korean railway export and analyzes the importance and competitiveness of the factors. This study also suggests policy directions for each factor and analyzes the current situation of the Korean railway industry. All influence factors identified in this study turned out to have high levels of importance. Influence factors with higher importance levels for each field are as follows: man-power/experience and skill/technology in the engineering field; price, information and man-power/experience in the construction field; and information, technology, and price in the manufacturing field. However, the level of competitiveness of the factors turned out to be low. This study also suggested policy directions for each influence factor: overall, they turned out to have high levels of importance. Policy directions with high importance for each field are as follows: strengthening overseas' human network, training/educating experts for overseas projects, and accumulating experiences through Official Development Assistance projects in the fields of engineering and construction; and cost reduction and strategical cooperation with foreign companies in the manufacturing field. However, interviewees' satisfaction levels for each policy area turned out to be low. Finally, policy measures for Korean railway export for each influence factor were suggested.
Establishing the Methodology of Economic Analysis to Take into Account Opportunistic Valuation for a Radio Communication & Train Control System
Cho, Shin-hyung ; Seo, Young-hyun ; Kho, Seung-young ; Rhee, Sung-mo ;
Journal of the Korean society for railway, volume 19, issue 3, 2016, Pages 373~379
DOI : 10.7782/JKSR.2016.19.3.373
Development of a train wireless signal control system using LTE-R technology is expected to have a great ripple effect to the existing signal control market. To make inroads into the international market, it is an urgent issue to practicalize the train wireless signal control system. Because it will require a huge budget to commercialize the wireless signal control system, it is necessary to analyze the feasibility beforehand, with a consideration of the domestic and foreign marketability and the impact on related industries. This study investigated the effect of the practicalization of train control system on future railway and national industrial sectors. We suggested the establishment of a framework for economic feasibility analysis, one that can provide criteria for opportunistic valuation. We also verified this framework through case analysis.
A Study on the Influences of the Estimation of Areas and Fees for Rental Facilities Affiliated with Subway Stations: A Case of Seoul Subway Lines 5 and 6
Jang, Jae Min ; Lee, Kyung Chul ; Gim, Tae-Hyoung Tommy ;
Journal of the Korean society for railway, volume 19, issue 3, 2016, Pages 380~387
DOI : 10.7782/JKSR.2016.19.3.380
Considering that the Seoul subway sector is expected to see extension of lines, addition of stations, and changes of operating companies, a review is needed to identify ways to eliminate or minimize financial deficits in its operation. As for deficits from the operation, additional businesses for extra income have been suggested as alternatives, but inasmuch as Western urban development (that of the subway containment area) may not be applicable to Korean settings, a practical alternative is to maximize income by efficient use of rental facilities that are located inside station properties. This alternative requires the estimation of appropriate facility size and rent for each station; few, however, have addressed this topic. At this juncture, this study aimed to draw an equation for estimating the sizes and rents of station properties by reflecting characteristics of lines and locations; a case study was performed for Subway Lines 5 and 6. Analytical findings are that rental facility sizes and rental incomes are affected mainly by the subway ridership and transport revenues, whereas the influence of ground-level commercial activity is relatively weak. A particularly great influence was found to be the value of apartment housing in areas through which the subway lines run. Stations on Line 5, which runs through areas of high-value housing, were assigned smaller facility sizes and higher rents than those on Line 6, which covers areas with relatively low housing value. The equation suggested in this study would make possible more practical feasibility studies when the need arises to estimate sales of new or extended facilities affiliated with stations.
Characteristics and Efficiency Analysis of Evolutionary Seoul Metropolitan Subway Network
Zzang, See-Young ; Lee, Kang-Won ;
Journal of the Korean society for railway, volume 19, issue 3, 2016, Pages 388~396
DOI : 10.7782/JKSR.2016.19.3.388
The metropolitan subway network of Seoul has gone through many evolutionary processes in past decades to disperse the floating population and improve the traffic flow. In this study, we analyzed how the structural characteristics and the efficiency of the subway network have changed according to the dynamic evolutionary processes of the metropolitan subway network of Seoul. We have also proposed new measures that can be used to characterize the structural properties of the subway network more practically. It is shown that the global efficiency is about 74%, which is higher than those of subway networks of foreign countries. It should also be considered that passenger flow between stations is even higher, at about 85%. Since the private lines, including line 9, the New Bundang line, the Uijeongbu line, and the Ever line do not release their traffic data since September, 2013, only 5 years of data from September, 2008 to September, 2013 is available. So, in this study we limit the analysis period to these 5 years.
An Analysis of Efficiency and Productivity of Metropolitan Urban Railway Corporation
Kim, Haegon ; Lee, Jinsun ;
Journal of the Korean society for railway, volume 19, issue 3, 2016, Pages 397~407
DOI : 10.7782/JKSR.2016.19.3.397
This study analyzed the efficiency change and the factors affecting productivity change for the six railway operation corporations that are local public enterprises; study was performed with the DEA-CCR Model and Malmquist Productivity Index, using data collected from 2010 to 2014. Since it was not feasible to collect data on the operating expenses and the number of employees of each of the lines, the efficiencies of each operation corporation were analyzed by integrating the operation corporations, and the Malmquist Productivity Index was used to investigate the trend of the periodical productivity change. Average efficiency for urban railway operation corporations was found to be higher in the case of the bigger corporations. In 2014, the Seoul Metro and the Daejeon Metropolitan Express Transit Corporations were analyzed and found to be the most efficient operation corporations. The Malmquist Productivity Index was used to determine the periodical change; the average MPI was 1.06, with a continuous increase of productivity. The analysis showed that changes of technology were generally more obvious than change of technology efficiency for all six operation corporations.