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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 15, Issue 6 - Dec 2012
Volume 15, Issue 5 - Oct 2012
Volume 15, Issue 4 - Aug 2012
Volume 15, Issue 3 - Jun 2012
Volume 15, Issue 2 - Apr 2012
Volume 15, Issue 1 - Feb 2012
Selecting the target year
A Study on the Economic Feasibility of Hybrid Bodyshell Made of Sandwich Composite Plate
Seo, Sung-Il ; Kim, Jung-Seok ; Cho, Se-Hyun ;
Journal of the Korean Society for Railway, volume 15, issue 2, 2012, Pages 97~103
DOI : 10.7782/JKSR.2012.15.2.097
Composite honeycomb sandwich plate is light and strong. It is easy to produce. It began to be applied to the bodyshell of rolling stock. Generally, weight saving amounts to 27%. However, the material cost of it is much higher than that of aluminum extrusion profile, which prevents popular use of it for bodyshell. In this paper, manufacturing processes of two light materials were compared to investigate cost impact. After cost breakdown was defined, economics of two materials was analyzed using the previous cost data. Easy production of composite bodyshell could compensate for higher material cost. Mass production of composite bodyshell can make the equipment cost lower for the composite bodyshell so that it may have strong competitiveness to the aluminum bodyshell. Operational energy saving due to weight reduction was also presented referring to the actual statistical data in a metro line.
A Study on the Air Pressure Endurance Test Device for High Speed Train Windows
Chang, Dae-Sung ; Yi, Won ;
Journal of the Korean Society for Railway, volume 15, issue 2, 2012, Pages 104~108
DOI : 10.7782/JKSR.2012.15.2.104
All of the Korean high speed train windows have been imported from abroad up to now. In this paper, the air pressure endurance test device for high speed train windows was studied and developed. This test device can create air pressure variation similar to train running real condition and carry out pressure endurance test according to international standard. Henceforward, this test device will be useful for domestic production of high speed train windows.
Evaluation of Impact Damage and Residual Compression Strength after Impact of Glass/Epoxy Laminate Composites for Lightweight Bogie Frame induced by Ballast-Flying Phenomena
Goo, Jun-Sung ; Shin, Kwang-Bok ; Kim, Jung-Suk ;
Journal of the Korean Society for Railway, volume 15, issue 2, 2012, Pages 109~115
DOI : 10.7782/JKSR.2012.15.2.109
In order to evaluate the effect of structural degradation of a GFRP composite bogie frame due to ballast-flying phenomena, the impact test and residual compression test after impact was conducted for glass fiber/epoxy 4-harness satin woven laminate composites applied to skin part of a bogie frame. The impact test was performed using a instrumented impact testing system with energy levels of 5J, 10J, and 20J, and the impactor was designed to have various ballast shapes such as sphere, cube, and cone to consider the ballasted track environments. The residual compression strength was tested to evaluate the degradation of mechanical properties of impact-damaged laminate composites. The results showed that the damage area and the degradation of residual compressive strength after impact for laminate composites was increased with increase of impact energy for all ballast shapes, and was particularly most influenced by ballast shape of cone.
Radiation Effects on PWM Controller of DC/DC Power Buck Converter
Lho, Young-Hwan ;
Journal of the Korean Society for Railway, volume 15, issue 2, 2012, Pages 116~121
DOI : 10.7782/JKSR.2012.15.2.116
DC/DC switching power converters produce DC output voltages from different DC input sources. The converter is used in regenerative braking of DC motors to return energy back in the supply, resulting in energy savings for the systems containing frequent stops. The DC/DC converter is composed of a PWM-IC (pulse width modulation integrated circuit) controller, a MOSFET (metal-oxide semi-conductor field-effect transistor), an inductor, capacitors, and resistors, etc. PWM is applied to control and regulate the total output voltage. In this paper, radiation shows the main influence on the changes in the electrical characteristics of comparator, operational amplifier, etc. in PWM-IC. In the PWM-IC operation, the missing pulses, the changes in pulse width, and the changes of the output waveform are studied by the simulation program with integrated circuit emphasis (SPICE) and compared with experiments.
A Study on the Application of Virtual Track Circuit by Considering Software Fault Tolerance Techniques in Depot
Lee, Myoung-Chol ; Ko, Young-Hwan ; Kim, Min-Seok ; Lee, Jong-Woo ;
Journal of the Korean Society for Railway, volume 15, issue 2, 2012, Pages 122~128
DOI : 10.7782/JKSR.2012.15.2.122
Considering structure of depot, it is impossible to install the track circuit systems due to iron-beam. Because rails and earth are connected by the iron-beam, there is much leakage current. So, it is hard to apply the track circuit systems. Thus, when trains go to the depot, sign which indicates existence of trains is used manually. In case of wrong sign, accidents occur such as train crash, derailment etc. Currently, location of trains has been found by using optical sensor in the depot to prevent the accidents. However, it costs a great deal to install and maintain the optical sensor. Therefore, this method is hardly used in train operation institutes. In this paper, virtual track circuit systems are introduced by using software program in the depot. Also, algorithm of the virtual track circuit systems is proposed. In case that signal is handled to the depot which is occupied by the train, safety is ensured by indicating sign which means existence of trains and stop signal. Also, proper fault tolerance techniques are proposed to the software by analyzing reliability and availability.
IPMSM Drives Using NPC 3-Level Inverters for the Next Generation High Speed Railway System
Kwon, Soon-Hwan ; Jin, Kang-Hwan ; Kim, Sung-Je ; Lee, Tae-Houng ; Kim, Yoon-Ho ;
Journal of the Korean Society for Railway, volume 15, issue 2, 2012, Pages 129~134
DOI : 10.7782/JKSR.2012.15.2.129
In this paper, speed control of IPMSM drives for the next generation domestic high speed railway system using NPC 3-level inverters is presented. The NPC multilevel inverter is suitable for the high-voltage and high-power motor drive system because it has advantages in that the voltage rating of the power semiconductor devices and output current harmonics are reduced. For the speed control of IPMSM using NPC 3-level inverters, maximum torque control is applied in the constant torque region, and filed weakening control is applied in the constant power region. Simulation programs based on MATLAB/Simulink are developed. Finally the designed system is verified and their characteristics are analyzed by the simulation results.
Core-loss Reduction on Permanent Magnet for IPMSM with Concentrated Winding
Lee, Hyung-Woo ; Park, Chan-Bae ; Lee, Byung-Song ;
Journal of the Korean Society for Railway, volume 15, issue 2, 2012, Pages 135~140
DOI : 10.7782/JKSR.2012.15.2.135
Interior Permanent Magnet Synchronous motors (IPMSM) with concentrated winding are superior to distributed winding in the power density point of view. But it causes huge amount of eddy current losses on the permanent magnet. This paper presents the optimal permanent magnet V-shape on the rotor of an interior permanent magnet synchronous motor to reduce the core losses and improve the performance. Each eddy current loss on permanent magnet has been investigated in detail by using FEM (Finite Element Method) instead of equivalent magnetic circuit network method in order to consider saturation and non-linear magnetic property. Simulation-based design of experiment is also applied to avoid large number of analyses according to each design parameter and consider expected interactions among parameters. Consequently, the optimal design to reduce the core loss on the permanent magnet while maintaining or improving motor performance is proposed by an optimization algorithm using regression equation derived and lastly, it is verified by FEM.
Analysis for Optimal Rail Grinding Amount by Rolling Contact Fatigue Test in High Speed Railway
Sung, Deok-Yong ; Chang, Ki-Sung ; Park, Yong-Gul ;
Journal of the Korean Society for Railway, volume 15, issue 2, 2012, Pages 141~146
DOI : 10.7782/JKSR.2012.15.2.141
The rail surface defects which are generated on repeated rolling contact fatigue are getting increased according to high speed, high density, and minimum weight. In addition, Increasing noise and vibration are affected by these also impact load generated as well. Because of this phenomenon, more serious and critical damages were occurred. In fact, in order to control them, the rail grinding amount in Korea. This study evaluated how depth of hardening on rail surface is formed and suggested optimal rail grinding amount by RCF(rolling contact fatigue) test with generated contact pressure between KTX wheel and UIC60 rail by applying FEM analysis. Therefore, the amount was generated approximately 0.2mm/20MGT to maintain integrity of rail surface by getting rid of depth of hardening on rail according to rail accumulated passing tonnage.
Analysis of Dynamic Behavior of Railway Bridge with Concrete Track
Min, Rak-Ki ; Sung, Deok-Yong ; Park, Yong-Gul ;
Journal of the Korean Society for Railway, volume 15, issue 2, 2012, Pages 147~153
DOI : 10.7782/JKSR.2012.15.2.147
Precise estimation f a structure`s dynamic characteristics is indispensable for ensuring stable dynamic response during life time especially for the structures which can experience resonance such as railway bridges. Especially, concrete track can change the modal properties of the railway bridge, through the contribution of stiffness as well as mass effects, generally only the mass effect is considered in dynamic analysis of the railway bridge. In this paper, static and dynamic behaviors of railway bridge with concrete track were investigated through experimental study. Also, numerical analysis was performed about considering only mass of concrete track and together with stiffness and mass of concrete track. These were compared with experiment value. Numerical analysis value considering together with stiffness and mass of concrete track was similar experiment value. Therefore, when dynamic analysis of railway bridge with concrete track is performed, the contribution of stiffness as well as mass effects for concrete track is considered.
Experimental Evaluation for Damping Ratio Limit of Railway Bridge according to Structure Types
Min, Rak-Ki ; Sung, Deok-Yong ; Park, Yong-Gul ;
Journal of the Korean Society for Railway, volume 15, issue 2, 2012, Pages 154~161
DOI : 10.7782/JKSR.2012.15.2.154
The damping ratio of railway bridge has become one of the most important issues in dynamic design and dynamic stability of railway bridge. In the present study, laboratory and field test were performed for railway bridges such as a twin I-shaped steel composite girder, PSC box, steel box, PSC, IPC, PRECOM, preflex. The damping ratio of railway bridge according to structure types was estimated by logarithmic decrement method. Therefore, magnitude, frequency and amplitude of load did not affect damping ratio of railway bridge. Also, damping ratio limit of steel composite and PSC bridges was evaluated in 1.0%.
Dynamic Interaction Analysis of Tilting Train and Curved Track
Chung, Keun-Young ; Koh, Tae-Hoon ;
Journal of the Korean Society for Railway, volume 15, issue 2, 2012, Pages 162~171
DOI : 10.7782/JKSR.2012.15.2.162
In this study, a new dynamic interaction analysis method for tilting trains and curved track is presented. Three dimensional lumped parameter vehicle elements are used to model tilting train, and the proposed analysis technique can simulate driving direction change of vehicle, the effect of track cant, wheel-rail contact angle, and tilting angle of tilting trains, etc. The proposed method passed several basic verification tests, and it is expected that the suggested method is applicable for practical problems.
An Analytical Study on Running Safety and Ride Comfort in Case of Superimposition of Vertical and Transition Curves
Um, Ju-Hwan ; Kim, Man-Cheol ; Lee, Il-Wha ; Goo, Byeong-Choon ;
Journal of the Korean Society for Railway, volume 15, issue 2, 2012, Pages 172~178
DOI : 10.7782/JKSR.2012.15.2.172
Superimposition of vertical and transition curves is not allowed for all types of tracks in Korean regulation of railway construction. However, this criterion has been established on the basis of difficulty of maintenance of the ballasted track. Comparing with the ballasted track, the concrete slab track has the advantage of maintenance and structural, which allows the superimposition of vertical and transition curves when it satisfies the criteria of running safety and riding comfort. In this study, running safety, ride comforts and track acting forces were analyzed and compared by numerical analysis using VAMPIRE program when the vertical and transition curves are superimposed for the ballasted track as well as the concrete slab track. From the analysis results, it was found that running safety, riding comforts and track acting forces in case of superimposition of vertical and transition curves for the both tracks meet all of the criteria. Therefore, although superimposition of vertical and transition curves for the ballasted track is not allowed because of a lot of maintenance works, it can be applied to the concrete slab track considering the advantage of maintenance and structural safety.
Environmental Benefit Analysis for Railroad-related Projects
Nam, Doo-Hee ; Huh, Hyun-Mu ; Lee, Jin-Sun ;
Journal of the Korean Society for Railway, volume 15, issue 2, 2012, Pages 179~184
DOI : 10.7782/JKSR.2012.15.2.179
Environmental impact is getting more attention in many feasibility studies for railroad-related projects and research items. For sustainable growth and green transportation, the benefits typically used for feasibility studies in railway-related projects, are composed mostly of economic criterions which is not considering growing attention on changing paradigm. Based on the analysis of current methodologies, improvements in estimating environmental impact especially on noise and pollution are suggested. Active steering bogie has been proposed to satisfy stabilizing and steering performance of railroad. This paper describes the feasibility study of the active steering bogie for a urban railway vehicle based on environment-related criteria.
A Column Generation Approach to Line Planning in Rail Freight Transportation
Park, Bum-Hwan ;
Journal of the Korean Society for Railway, volume 15, issue 2, 2012, Pages 185~192
DOI : 10.7782/JKSR.2012.15.2.185
Line planning is to determine the frequency of trains on each line to satisfy origin-destination demand while minimizing total operation cost. However, different from the line planning in passenger transportation, it is more important at which intermediate stations each train should be stopped and shunted because the freight car handling works like drop-off or(and) pick-up can incur much time and high cost so that the delay deteriorates the quality of rail freight transportation service. We present an optimization model for constructing line plan in rail freight transportation to simultaneously minimize the train operation cost and total transportation time of freights. And we suggest a column generation approach for our problem, which can solve the real network instances in reasonable computation times.
A Comparative Study on Railway Accident Safety Statistics among Nations and Other Transportation Modes
Kwak, Sang-Log ;
Journal of the Korean Society for Railway, volume 15, issue 2, 2012, Pages 193~198
DOI : 10.7782/JKSR.2012.15.2.193
As a result of investment in railway safety since 2004, railway accidents have been reduced by half and we reached a high level of safety compared to other countries. But people are still worries about railway accident, and want safer railway. It is difficult to determine which level of safety must be achieved due to lack of comparative studies on railway safety among different countries and other transportation modes. In this study, a comparative study on railway accident statistics and various transportation modes is performed. The results of this research can be used for the determination of weak areas of railway safety and the level of safety to be achieved.
The Effects on Job Insecurity to the Job Performance in Railroad Organizations: Mediated by Organizational Citizenship Behavior
Kim, Dae-Won ; Choi, Yun-Geun ; Park, Ki-Chan ;
Journal of the Korean Society for Railway, volume 15, issue 2, 2012, Pages 199~204
DOI : 10.7782/JKSR.2012.15.2.199
This study examines the mediating effect of Organizational Citizenship Behavior in the relationship between Job Insecurity and self-reported Job Performance. 207 employees from 4 Railroad Organizations (Korail, Seoul Metro, Incheon Metro, Metro 9) are selected as the main target of this study. Based on advanced researches, hypothesizes are developed and according to received questionnaires, SPSS 18.0 is used for testing empirically. Result shows that with Mediating variable OCB, Job Insecurity is negatively associated with self-reported Job Performance. And because OCB is complete mediating in the relationship between Job Insecurity and self-reported Job Performance, actually, OCB is shown to play a very important role in Job Insecurity.
Research on the Intention to Adopt a Railway as an International Transportation Mode in Korea: A Focus on Transcontinental Railways (KTAR)
Choi, Kyoung-Suk ; Song, Chae-Hun ;
Journal of the Korean Society for Railway, volume 15, issue 2, 2012, Pages 205~215
DOI : 10.7782/JKSR.2012.15.2.205
The purpose of this research is to identify the factors affecting the intention to adopt a transcontinental railway in Korea. We develop an empirically testable model that demonstrates the effects of factors including cost, service, and efficiency of railway transportation, on modal shift intention to railway, attitude of a Railway, and intention to adopt a Transcontinental Railway (KTAR) as a railway transportation mode in the end. A survey method enables us to analyze the model with a structural equation modeling. The empirical analysis reveals that two most influential factors-the modal shift to railway transportation and the attitude of a Railway-play roles in determining intention to adopt the Transcontinental Railway (KTAR). Of the factors of transportation mode, transportation cost has a greater impact than transportation service and transportation efficiency on the intention to adopt a Transcontinental Railway (KTAR).