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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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Korean Society for Railway
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Volume & Issues
Volume 14, Issue 6 - Dec 2011
Volume 14, Issue 5 - Oct 2011
Volume 14, Issue 4 - Aug 2011
Volume 14, Issue 3 - Jun 2011
Volume 14, Issue 2 - Apr 2011
Volume 14, Issue 1 - Feb 2011
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Development of a Theoretical Wheelset Model to Predict Wheel-climbing Derailment Behaviors Caused by Rolling Stock Collision
Choi, Se-Young ; Koo, Jeong-Seo ; You, Won-Hee ;
Journal of the Korean Society for Railway, volume 14, issue 3, 2011, Pages 203~210
DOI : 10.7782/JKSR.2011.14.3.203
This study formulates the theoretical wheel-set model to evaluate wheel-climbing derailments of rolling stock due to collision, and verifies this theory with dynamic simulations. The impact forces occurring during collision are transmitted from a car body to axles through suspensions. As a result of combinations of horizontal and vertical forces applied to axles, rolling stock may lead to derailment. The derailment type will depend on the combinations of the horizontal and vertical forces, flange angle and friction coefficient. According to collision conditions, the wheel-lift, wheel-climbing or roll-over derailments can occur between wheel and rail. In this theoretical derailment model of wheelset, the wheel-climbing derailment types are classified into Climb-over, Climb/roll-over, and pure Roll-over according to derailment mechanism between wheel and rail, and we proposed the theoretical conditions to generate each derailment mechanism. The theoretical wheel-set model was verified by dynamic simulations.
A Study to Estimate the Emitted Sound Power from the Rolling Stock
Lee, Young-Yeob ; Kim, Jae-Chul ; Lee, Hi-Sung ;
Journal of the Korean Society for Railway, volume 14, issue 3, 2011, Pages 211~215
DOI : 10.7782/JKSR.2011.14.3.211
Generally, sound power is one of the most significant factors to predict and assess noise from sound sources. However, many researchers developed indirect methods to calculate the sound power with noise level because it is impossible to measure sound power directly while a train is running. In this paper, we propose a method to estimate sound power generated due to wheel/rail interaction and propulsive equipment from the measurement of noise emitted from rolling stocks and verify the estimation method by comparing with the other sound power estimation formula. We also analyze the sound power of rolling stocks which are operating in domestic lines such as EMU, Mukoonghwa, KTX using the method proposed in this paper.
A study on Determining Maintenance Intervals Considering the Maintenance Effect for the PDS in Metro EMU
Lee, Duk-Gyu ; Son, Young-Jin ; Lee, Hi-Sung ;
Journal of the Korean Society for Railway, volume 14, issue 3, 2011, Pages 216~221
DOI : 10.7782/JKSR.2011.14.3.216
An important problem in reliability analysis for repairable systems is to model the maintenance effect. The most of researches have assumed two extreme cases; one is perfect maintenance and the other is minimal maintenance. However, many of maintenances performed by domestic subway operators are imperfect maintenances which have the effect between both of two extreme cases. This article deals with the problem determining the imperfect preventive maintenance intervals based on failure data in units of the PDS(passenger door system) in Metro EMU. This paper deals with a case study on determining imperfect maintenance interval by using the level of maintenance effect through reliability analysis of PDS.
Mechanical Loads of Dropper for High Speed Electric Railway
Lee, Gi-Chun ; Lee, Tae-Hoon ; Lee, Jong-Woo ;
Journal of the Korean Society for Railway, volume 14, issue 3, 2011, Pages 222~227
DOI : 10.7782/JKSR.2011.14.3.222
The dropper supports the contact wire and is attached using various types of dropper clips on the catenary. Droppers are subject to mechanical stress from buckling during the passage of pantographs. In order to investigate failure causes for the high speed line dropper, theoretical analyses and experiments have been carried out. In this paper, mathematical formulas are derived for the pre-sag of the dropper static load. The measured values in the experiment were similar to the theoretical predictions. To analyze the cause on fracture of dropper wire, we have conducted analysis such as SEM(Scanning Electron Microscope) of fractured specimens in the field and new specimens. Finally, we performed measurement for the variation of dynamic load on the dropper when a pantograph moved at 300km/h under the Korean high speed overhead line. If such mechanical load occur repeatedly with every passing pantograph, it is possible that the dropper wire will break due to fatigue. This results will be used for special management of high speed catenary system maintenance and life estimation of dropper.
A Study on Speech Recognition based on Phoneme for Korean Subway Station Names
Kim, Beom-Seung ; Kim, Soon-Hyob ;
Journal of the Korean Society for Railway, volume 14, issue 3, 2011, Pages 228~233
DOI : 10.7782/JKSR.2011.14.3.228
This paper presented the method about the Implementation of Speech Recognition based on phoneme considering the phonological characteristic for Korean Subway Station Names. The Pronunciation dictionary considering PLU set and phonological variations with four Case in order to select the optimum PLU used for Speech Recognition based on phoneme for Korean Subway Station Names was comprised and the recognition rate was estimated. In the case of the applied PLU, we could know the optimum recognition rate(97.74%) be shown in the triphone model in case of considering the recognition unit division of the initial consonant and final consonant and phonological variations.
Evaluation of Train Running Safety During Construction of Temporary Bridge on Existing Railway
Eum, Ki-Young ; Bae, Jae-Hyoung ; Choi, Chan-Yong ;
Journal of the Korean Society for Railway, volume 14, issue 3, 2011, Pages 234~239
DOI : 10.7782/JKSR.2011.14.3.234
Installing the temporary bridge after excavating the railway requires installing movable cross beam, but as it doesn`t requires isolating the catenary or cutting the rail, it`s applicable to double-track with frequent operation. In this study, a displacement meter was placed on temporary bridge to monitor the displacement pattern in curve section (R400) completed using temporary bridge method, and wheel load, lateral pressure and derailment coefficient were measured to evaluate the load imposed on track and the stability in curve section (R400) for quantitative evaluation of training running safety. As a result of the measurement, when trains passing over a temporary bridge, the maximum value of Wheel load and Lateral Force is analyzed as the 51% and 81% of standard level according to foreign country`s performance tests, There is no trouble with stability analysis in Wheel load and Lateral Force occurring. Additionally, Wheel load and Lateral Force considered as the safety standard are tested 49% of limiting value regardless of trains, which the norm value quite well, there is no problem with train running.
Finite Element Analysis of Concrete Railway Sleeper Damaged by Freezing Force of Water Penetrated into the Inserts
Moon, Do-Young ; Zi, Goang-Seup ; Kim, Jin-Gyun ; Jang, Seung-Yup ;
Journal of the Korean Society for Railway, volume 14, issue 3, 2011, Pages 240~247
DOI : 10.7782/JKSR.2011.14.3.240
Finite element analysis was undertaken to investigate the effect of freezing force of water unexpectedly penetrated into inserts used in railway sleeper on pullout capacity of anchor bolts for fixing base-plate onto concrete sleeper. Based on the in-situ investigation and measurement of geometry of railway sleeper and rail-fastener, the railway sleeper was modeled by 3D solid elements. Nonlinear and fracture properties for the finite element model were assumed according to CEB-FIP 1990 model code. And the pullout maximum load of anchor bolt obtained from the model developed was compared with experimental pullout maximum load presented by KRRI for verification of the model. Using this model, the effect of position of anchor bolt, amount of fastening force applied to the anchor bolt, and compressive strength of concrete on pull-out capacity of anchor bolts installed in railway sleeper was investigated. As a result, it is found that concrete railway sleepers could be damaged by the pressure due to freezing of water penetrated into inserts. And the pullout capacity of anchor bolt close to center of railway is slightly greater than that of the others.
The Evaluation of Track Impact Factor on the Various Track Type in Urban Transit
Choi, Jung-Youl ; Park, Yong-Gul ; Lee, Sang-Min ;
Journal of the Korean Society for Railway, volume 14, issue 3, 2011, Pages 248~255
DOI : 10.7782/JKSR.2011.14.3.248
Impact factor of concrete and ballast track which has been used in Korea railway was applied to equation (1+0.513V/100) from AREA. As the use of this equation, overcapacity of track design might be occurred. Therefore, this study compared impact of ballast track (well, bad) and concrete track (sleeper embeded system, rail floating and sleeper floating) by field test to analyzing dynamic effect of track structure`s characterstic and wheel load on service line. In addition, it suggested a method to generate reasonable impact factor on each track type.
Cross-Sectional Imaging of Elastic Modulus for Railway Trackbed under Ballast for Identification of Potential Settlement
Joh, Sung-Ho ; Hwang, Seon-Keun ; Hassanul, Raja ; Abd Rahman, Norinah ;
Journal of the Korean Society for Railway, volume 14, issue 3, 2011, Pages 256~261
DOI : 10.7782/JKSR.2011.14.3.256
Recently a limited section of trackbed with ballast at KTX railway were reported to have settled down and led to problems such as reduced speed and passenger discomfort. Therefore, an urgent remedy for the settled trackbed is required to recover normal operation of KTX trains. In this paper, a new technique is proposed to visualize the elastic modulus of cross sections at railway trackbeds under ballast for practical identification of potential settlement. The proposed technique is based on ICSW technique, enabling use of impact source and overcoming inherent limitations of CSW method. To verify validity and feasibility of the proposed method, the method was employed to construct cross-sectional images of elastic modulus of two railway trackbeds and compared with other tests such as SASW, PBT, DCP and portable FWD tests.
A Study on the Evaluation of Track Support Stiffness on the Various Track Type in Urban Transit
Lee, Dong-Wook ; Park, Yong-Gul ; Choi, Jung-Youl ;
Journal of the Korean Society for Railway, volume 14, issue 3, 2011, Pages 262~270
DOI : 10.7782/JKSR.2011.14.3.262
Track support stiffness which affected track maintenance and riding comfort had a big effect on the track and train. Also, track support stiffness of the track design which was based on theory differs from track support stiffness of the track generated on the field. Track support stiffness was generated by several factors such as dynamic wheel loads, vertical displacement of track, and stress at rail bottom on the field test. With the results of the field test was compared with theoretical value. This paper analyzed that track support stiffness of ballast depended on condition of ballast, and support stiffness of concrete track also depended on the characteristic of track structures such as, normal elastic fastening system, rail floating system and sleeper floating system. However, on the ballast and concrete track, the designed track support stiffness was underestimated less than the measured track support stiffness. When the track condition was estimated on service line, it would not consider the track condition on the field. Therefore, this study proposed the various track type and the range of track support stiffness based on the experimental test.
The Evaluation of GHG Emissions in Railroad Construction Sector
Lee, Jae-Young ; Jung, Woo-Sung ; Hwang, In-Hwan ; Kim, Yong-Ki ;
Journal of the Korean Society for Railway, volume 14, issue 3, 2011, Pages 271~275
DOI : 10.7782/JKSR.2011.14.3.271
According to governmental policies for green growth, the increase in the traffic volume of railroad is a representative method to reduce total greenhouse gas (GHG) emitted from transport. Comprehensive assessment for the GHG emission of railroad has been studied to compare the difference of transport modes just in the operating step excluded the construction step. The purpose of this study was to evaluate GHG emissions in railroad construction sector. The targets were some construction works for civil, track, building, and electric system in A line. The GHG emission source of constructing railroad infrastructure was mainly the energy consumption of heavy equipments. As a result, the civil construction sector showed more than 96% of total GHG emissions and its specific GHG emission was 2.191 ton
. Also, the specific GHG emissions of civil construction works were of the order: earthworks > tunnels > bridges > station. In future, it will be required to calculate the overall GHG emission of railroad through life cycle approaches including operation, maintenance and disposal step.
A LOGIT based Traffic Assignment Model Considering Passenger Transfer on Railway Network
Park, Bum-Hwan ; Rho, Hag-Lae ; Cheon, Seung-Hoon ; Lee, Jin-Sun ;
Journal of the Korean Society for Railway, volume 14, issue 3, 2011, Pages 276~284
DOI : 10.7782/JKSR.2011.14.3.276
In our study, we present a new LOGIT-based traffic assignment model applicable to intercity railway network. Most traffic assignment models have been developed for public transit assignment in urban area, so that they are known to produce unrealistic results in intercity railway demand analysis. Especially, since the introduction of KTX, more passengers are using a route including KTX service and the schedule becomes more compatible with transfer. Our study presents a new LOGIT-based traffic assignment model considering passenger transfer. To do so, we suggest a new route search algorithm to find K paths with non increasing order in the utility value.
An empirical Analysis of Scientific and Technological Performance for the Railroad R&D through the Cross-sectional Analysis
Park, Man-Soo ; Bang, Yoon-Sock ; Lee, Hi-Sung ;
Journal of the Korean Society for Railway, volume 14, issue 3, 2011, Pages 285~294
DOI : 10.7782/JKSR.2011.14.3.285
An analysis of railroad industry has been insufficient whereas there are lots of analysis of accumulation of technology, economic performances and ripple effects for macroscopic view and other industry of R&D investments. This study decided intellectual rights, patent, and paper as common indicators of scientific and technological performances for setting up performance targets through surveying and analysis of preceding study and verified a appropriateness of scientific and technological performances for railroad R&D 11 projects which were successfully finished. Preceding study has been set up performance targets by research investments as input, but this study made a performance target by model through a cross-sectional and residual analysis of performances of railroad R&D 11 Projects in applying research investments, capital investments and inner labor cost per man and research time as inputs, and verified a validity and a empirical analysis through analysis of other project.
A Study on Setting Up National Railway Safety Target
Kwak, Sang-Log ;
Journal of the Korean Society for Railway, volume 14, issue 3, 2011, Pages 295~299
DOI : 10.7782/JKSR.2011.14.3.295
According to the national railway safety plan 1 billion US$ have been invested in railway industry every year. As a result, railway accident rate has been reduce to half recent 6 years. Currently, Korea has 3 kinds of national railway safety target, which are accident fatalities, train accident rate, and passenger fatality per passenger kilometer. Increase of railway passengers and train operating companies force to set up new safety target. Current safety target cannot reflect train operator`s safety activities because they include suicide and trespass related accidents, which are hard to be controlled by the operators. In order to reflect to the national railway safety plan, new safety targets are proposed in this study.
A Study on Labor-Management Cooperation and Corporation Performance resulted from Integrated Human Resource Management Types - Focus on Urban Railroad Corporations -
HwangBo, Jak ; Heo, Chan-Yeong ; Ju, Youg-Jun ;
Journal of the Korean Society for Railway, volume 14, issue 3, 2011, Pages 300~311
DOI : 10.7782/JKSR.2011.14.3.300
In this study, the differences of labor-management cooperation and corporation performance resulted from integrated human resource management types is investigated for 12 urban railroad corporations and then the effect of labormanagement cooperation on the corporation performance is also verified. The results show that the labor-management cooperation and the corporation performance of "closed immersion type" and "opened flexibility type" integrated human resource managements are higher than those of "conservative management type" and "poor management type" integrated human resource managements. As a result of the effect of labor-management cooperation on the corporation performance, it is revealed that "individual cooperation" affects all the corporation performances such as train operation stability, customer`s satisfaction, management innovation, self-supporting management, and job satisfaction, whereas "collective cooperation" affects only two coporation performances, management innovation and job satisfaction.