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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 10, Issue 6 - Dec 2007
Volume 10, Issue 5 - Oct 2007
Volume 10, Issue 4 - Aug 2007
Volume 10, Issue 3 - Jun 2007
Volume 10, Issue 2 - Apr 2007
Volume 10, Issue 1 - Feb 2007
Selecting the target year
Settlement of Embankment and Foundation for Concrete Track of Gyungbu High Speed Railroad (II)
Kim, Dae-Sang ; Park, Seong-Yong ; Shin, Min-Ho ; Lee, Hyeon-Jung ; Kim, Hyun-Ki ;
Journal of the Korean society for railway, volume 10, issue 5, 2007, Pages 457~462
An application of concrete track is being activity processed for the construction of Korean railroad. The concrete track has an advantage to decrease the maintenance fee, but is very difficult to control the settlement of ground and embankment consisting of substructure of concrete track below the allowable settlement level. This is the reason why the measurement and evaluation of both ground and embankment settlement before the installation of the concrete track is very important. One ground, a lower subgrade, and five surface settlements are measured to understand the settlement behavior of ground and embankment settlement. The period to measure settlements was more than 1 year after the completion of embankment. In this test site, ground settlement was over during the construction of embankment, but the embankment settlement are being continuously proceeded after the completion of embankment. The settlement velocity gradually is slowing down as time goes by. This paper also analysed the reasons of abrupt settlement increase and concluded that the rainfall was one of the important reason to increase settlement rate.
Analysis on Factors Affecting the Vibration of the Ballast Track in Kyeong-Bu High Speed Line
Kim, Man-Cheol ;
Journal of the Korean society for railway, volume 10, issue 5, 2007, Pages 463~472
In this paper, the correlation between the vibration characteristics of the track components and the parameters affecting the vibration is analysed. To do it, the accelerations of each track component such as rails, sleepers and ballast are measured in Kyong-Bu high-speed line. The RMS values of the measured data are calculated and the pad stiffness, the longitudinal irregularity, running velocity and the corrugation, are considered as the parameters in the viewpoint of track. By using the linear regression, the correlation coefficient is calculated to analyse the relationship. Also, the 1/3 Octave analysis is calculated to analyse the dominant frequency band of tile vibrations of the track components.
Analysis on Running Safety for KTX Vehicle
Kim, Jae-Chul ; Ham, Young-Sam ;
Journal of the Korean society for railway, volume 10, issue 5, 2007, Pages 473~479
Lateral vibration at the tail of KTX train was found during the acceptance test. In order to settle the problem of lateral vibration, the wheel conicity was changed 1/40 to 1/20. However, we should evaluate the running safety of vehicle with 1/20 wheel conicity because modification of wheel conicity may cause the running performance to be worse and critical speed to reduce. In this paper, we calculate critical speed of KTX bogie as wheel conicity increase and analyze the running safety for KTX that has 20 car trainset formation using VAMPIRE. and compare with the test results of KHST to validate analysis results on high speed line. A analysis results show that critical speed of 0.3 wheel conicity is over 375km/h and curving performance of 1/20wheel conicity is better than 1/40. Also, we examinate the running performance of KTX to check out possibility to increase speed of KTX on conventional line. A analysis results show that it is possible to increase up to 10% the speed of KTX on tangent line but KTX on a curved line should be operated with the speed of conventional train.
The Development of Models and the Characteristics for Subway Noise Using the Classification and Regression Trees
Kim, Tae-Ho ; Lee, Jae-Myung ; Won, Jai-Mu ; Song, In-Suk ;
Journal of the Korean society for railway, volume 10, issue 5, 2007, Pages 480~486
The subway is a necessary public transportation in big cities, which many citizens are using now. However, the demands for subway inner circumstance by citizens are growing recently. Among them, the noise problem is the hot issue to be solved. So, in this study we classified the characteristics of subway noise using the classification and regression trees (CART) based on noise level data in line No. 5 in Seoul. After that We developed the models for effect of subway noise and analyzed the characteristics through it. The result of this study is that we need to consider the type of geometry design and operational factors when the problem of subway noise improves, because the factors which weigh with subway noise are different by type of geometry and operational part.
A Study of Aerodynamical Effects for Determining the Distance between Track Centers by using Real Train Experiment
Nam, Seong-Won ; Kwon, Hyeok-Bin ;
Journal of the Korean society for railway, volume 10, issue 5, 2007, Pages 487~491
When constructing a high-speed railroad, the reduction of the distance between track centers and the width of track bed will save the construction cost. However the shortening the distance between track centers may cause the stability problems due to higher wind pressure. Therefore the extensive technical review and aerodynamical study should be performed to determine the adequate distance between track centers. In this study, the impact that the increase in wind pressure due to the change of aerodynamic phenomena with the change of the distance between track centers may have on two trains passing by each other was predicted, and the stability of train operation was analyzed in order to review the distance between track centers suitable to Honam HSR trains. And we estimated the aerodynamical effects by the results of the real train experiments.
A Study on the Assessment of Running Safety of Railway Vehicle passing through Curve
Park, Kwang-Soo ; Lee, Hi-Sung ;
Journal of the Korean society for railway, volume 10, issue 5, 2007, Pages 492~498
For the running safety assessment of Saemaul train passing through curves, an analysis model for multibody system has been developed. By using this model and ADAMS/Rail, sensitivity analyses depending on the variation of parameters related to the derailment coefficients have been conducted. At low speed, the derailment coefficient and the unload ratio of right wheel showed higher than left wheel, while those of left wheel showed higher than right wheel at high speed. According to decrease of curve radius, the derailment coefficient and the unload ratio were increased. When the length of transition curve was increased, the derailment coefficient was increased but there was no change on the unload ratio. According to the increase of cant, the derailment coefficient and the unload rate were increased.
A Behavior Analysis of HSR Concrete Slab Track under Variety of Rail Pad Static Stiffness on Fatigue Effect
Park, Yong-Gul ; Kang, Kee-Dong ; Choi, Jung-Youl ;
Journal of the Korean society for railway, volume 10, issue 5, 2007, Pages 499~505
The major effective of this study is to investigate the fatigue effects of rail pad on High Speed Railway with concrete slab track system. It analyzed the mechanical behaviors of HSR concrete slab track with applying rail pad stiffness based on fatigue effect (hardening and increasing stiffness) on the 3-dimensional FE analysis and laboratory test for static & dynamic characteristics. As a result, the hardening of rail pad due to fatigue loading condition are negative effect for the static & dynamic response of concrete stab track which is before act on fatigue effect. The analytical and experimental study are carried out to investigate rail pad on fatigue effected increase vertical acceleration and stress and decrease suitable deflection on slab track. And rail pad based on fatigue effect induced dynamic maximum stresses, the increase of damage of slab track is predicted by adopting fatigue effected rail pad. after due consideration. The servicing HSR concrete slab track with resilient track system has need of the reasonable determination after due consideration fatigue effect of rail pad stiffness which could be reducing the effect of static and dynamic behavior that degradation phenomenon of structure by an unusual response characteristic and a drop durability.
Development of a Computer Program to Evaluate Smoke Volume Flow rate and Temperature for Tunnel Fires
Park, Won-Hee ;
Journal of the Korean society for railway, volume 10, issue 5, 2007, Pages 506~510
Smoke temperature and volume flow rate in a tunnel fire are calculated. To obtain realistic results, enthalpy of smoke which composites combustion gases and entrainment air is calculated from curvefit polynomials by temperature. A user-friendly computer program for them is also developed. This program might be used for a good engineering tool in design of fire safety and mock/reduced-scale fire tests in a tunnel.
A Study on Smoke Extract Vents in a Subway with Screen door by Evacuation Performance Evaluation through RSET vs. ASET based on Computer Simulations
Park, Hyung-Joo ; Lee, Young-Jae ; Shin, Dong-Cheol ; Baek, Dong-Ho ;
Journal of the Korean society for railway, volume 10, issue 5, 2007, Pages 511~519
This study provides comprehensive design improvements covering technical issues concerning life safety matter In case of fire train stoppage in the middle of a tunnel. Recently Government announced that most of subway platforms will have screen doors in 3 years. Therefore, many fire safety engineers considered that they may contribute on life safety on train stoppage in tunnel. Especially The screen door can protect platform from smoke along tunnel ceiling when fire train stopped in tunnel. The study showed that platform ventilation ducts and the a tunnel ventilation chimney in the middle of tunnel in exiting subway tunnel could not guarantee life safety ability in terms of RSET vs. ASET comparison. Furthermore during evacuation process many peoples may be threatened from the smoke spread from the origin of fire. Although only additional vertical route can be installed in tunnels In order to decrease RSET, it will costs high or no spaces remains in outside on the road. The study suggested that increase of ASET can be best solution without additional escape route, therefore alternative design methods suggested on the base of simulation results. Finally the study shows alternative methods can give good result in terms of evacuation performance evaluation. The evacuation performance evaluation helps the decision-maker to determine the preferred alternatives or upgrades to existing tunnel infrastructure and other measure to meet safety objectives. Finally, the study details the effectiveness of measures the can be taken to reduce the risk of incidents in subway tunnels.
A Study on the Construction of Reliability Centered Maintenance System for Korean Tilting Train
Seo, Sung-Il ; Mun, Hyung-Suk ; Eum, Ki-Young ;
Journal of the Korean society for railway, volume 10, issue 5, 2007, Pages 520~526
A Study on Power Supply Method Design for Hot Standby Sparing System via Reliability Modeling
Shin, Duck-O ; Lee, Kang-Mi ; Lee, Jae-Ho ; Kim, Yong-Kyu ;
Journal of the Korean society for railway, volume 10, issue 5, 2007, Pages 527~532
In this paper, we suggest those two design plans for power supply method of Hot Standby Sparing System; one is the plan using MTBF based on Constant Failure Rate, and the plan using Reliability Function is the other. Traditionally, RBD (Reliability Block Diagram) is used for reliability prediction which is required to meet any requirements before system operation. However, the system that has redundancy, such as Hot Standby Sparing System, Is not suitable for system reliability modeling using combination model, such as RBD. In this paper, therefore, we demonstrate that for redundancy controller, redundancy modeling design toward fault occurrence design is more effective to build up a system with higher reliability and achieve the effectiveness of loss cost due to maintenance and failure occurred in operation, rather than combinational modeling design.
A Study on the Aptitude Test for Train Drivers
Shin, Tack-Hyun ; Kook, Kwang-Ho ; Park, Keon-Ok ; Han, Sang-Wook ;
Journal of the Korean society for railway, volume 10, issue 5, 2007, Pages 533~539
Since 1971, the aptitude test for domestic train drivers has long been maintained without any overall change. With the revision of the Railroad Safety Act in 2006. the aptitude test was changed from the type of written and skill test into the type of question-and-answer and reaction test. However, the main structure of the test is being maintained unchanged. In this paper, we focus our attention on the improvement of the present aptitude test. We surveyed on two groups, one is the railroad expert group and another is train driver's group, questioning about the importance of the domestic and foreign aptitude test items. Based on the analysis, we suggest desirable aptitude test system for the railroad safety.
Safety evaluation of dynamic behavior of Korean tilting train
Yoon, Ji-Won ; Kim, Nam-Po ; Kim, Young-Guk ; Kim, Seog-Won ; Park, Tae-Won ;
Journal of the Korean society for railway, volume 10, issue 5, 2007, Pages 540~545
The tilting train is able to tilt its body towards the center of the turning radius, preventing roll-over of the train as it runs on a curved rail at high-speed. This train, widely accepted for commercial purpose internationally, is very beneficial in that the operating time is shortened without much capital investment to the infrastructure where there are many curved rails. Over several years, the Korea Railroad Research Institute (KRRI) has developed such a train. In this paper, the safety of the Korean tilting train express (TTX) is investigated using a dynamic simulation model. Since proper safety standards have not been established for the TTX, those for the Korean train express (KTX) is employed to analyze the safety and ride comfort of the TTX. This study is useful in predicting the behavior of the TTX and ride comfort, and conforms that designed TTX is stable enough to satisfy the safety standards. It would be useful to recommend proper normal operating speed and determine the maximum safety speed, according to the result. Furthermore, it would be possible to provide basic reference data when analyzing the dynamic effect of the catenary system and the fatigue of the bogie.
The Effect of Fretting Wear on Fatigue Crack Initiation Site of Press-fitted Shaft
Lee, Dong-Hyong ; Kwon, Seok-Jin ; Choi, Jae-Boong ; Kim, Young-Jin ;
Journal of the Korean society for railway, volume 10, issue 5, 2007, Pages 546~553
The objective of the present paper is to evaluate the effect of the evolution of contact surface profile by fretting wear on the contact stress distribution and fatigue crack initiation site of press-fitted shaft by means of an analytical method based on experimental data. A finite element analysis was performed to analyze the stress states of press-fitted shaft, considering the worn contact surface profiles of shaft. The evolutions of contact stress as wearing of contact surface were analyzed by finite element analysis and fatigue crack nucleation sites were evaluated by fretting fatigue damage parameter (FFDP) md multiaxial fatigue criteria. It is found that the stress concentration of a contact edge in press-fitted sha손 decreases rapidly at the initial stage of total fatigue life, and its location shifts from the contact edge to the inside due to fretting wear as increasing of fatigue cycles. Thus the transition of crack nucleation position in press-fitted shaft is mainly caused by stress change of a contact edge due to the evolution of contact surface profile by fretting wear. Therefore, it is suggested that the nucleation of multiple cracks on fretted surface of press fits is strongly related to the evolution of surface profile at the initial stage of total fatigue life.
Steel Box Girder Bridge Models of Light Rail Transit with HR Plate
Lee, Seong-Haeng ; Yim, Chae-Sun ; Hwang, Nak-Yuen ; Jung, Kyoung-Sup ;
Journal of the Korean society for railway, volume 10, issue 5, 2007, Pages 554~562
To increase the demand of HR Plate with thickness up to 22mm, it is necessary that HR Plate is applicable to full member in steel bridge including main girder. In this study, availabilities of the narrow steel box girder of light railway transit with HR Plate width as a main member are discussed. Computational analysis is performed in 15 bridge models of light railway transit with beam element and plate element. As an analysis results, three models in tight railway transit are presented. In conclusion, it is validated that HR Plate can be applying to narrow steel box girder in the light railway transit.
A Study on Flow Characteristics of a Separate Triangular Bar Differential Pressure Flow Meter for Measuring Exhaust Flow Rate of Diesel Engine
Lee, Choong-Hoon ; Kim, Kwang-Il ; Kim, Min-Chang ; Park, Dong-Sun ;
Journal of the Korean society for railway, volume 10, issue 5, 2007, Pages 563~568
A separate triangular bar type differential pressure flow meter was developed for measuring exhaust gas flow rate from Diesel engine. Three kinds of the separate triangular bar flow meters whose aerodynamic angles are different one another are made and evaluated, respectively. The experimental results show that an aerodynamic shape has a effect on the pressure difference between upstream and downstream at the flow meter, that is, the thinner the shape of the separate triangular bar flow meter is, the smaller the pressure difference at the flow meter is. The separate triangular bar type flow meter was calibrated at both cold and high temperature of the gas flow. A burner system was designed for raising the gas temperature and it was well operated in controlling the gas temperature. An empirical correlation between mass flow rate and differential pressure at the separate triangular bar flow meter was obtained and the empirical correlation was also corrected by the gas temperature.
A Study on an Algorithm using Multicommodity Network Flow Model for Railroad Evacuation Routing Plan
Chang, Byung-Man ; Kim, Si-Gon ;
Journal of the Korean society for railway, volume 10, issue 5, 2007, Pages 569~575
This paper presents a study on a Dijkstra algorithm for shortest paths to destinations and a modified algorithm of Multicommodity Network Flow Problem Model with a network transformation for evacuation planning from railroad accident in a directed network.
A study on upper extremity muscle fatigue changes of train driver
Jang, Hye-Yoen ; Lee, Yung-Gi ; Jang, Jae-Ho ; Kim, Tae-Sik ; Hong, Sung-Jun ; Han, Chang-Soo ; Han, Jung-Soo ; Ahn, Jae-Yong ;
Journal of the Korean society for railway, volume 10, issue 5, 2007, Pages 576~581
The purpose of this study is to investigate changes in the forearm-muscle fatigue of a train driver operating the MasCon by using EMG (electromyogram) measurement technique. Train drivers usually use their forearm 4hours/day for normal operation. Accordingly, few different EMG signals of deltoid, biceps brachii, brachioradialis, flexor carpi ulnaris muscle of upper extremity have been measured and analyzed. The raw EMG Signals have been converted into median frequency using spectrum analysis. As the result, 80% of 10 subjects (real train drivers) showed that median frequency value of all four muscles has been reduced after 30 minutes of train operation. This results demonstrated that operating MasCon for 30 minutes could induce muscle fatigue.
Roadbed Bearing Capacity Associated with Estimated Impact Factor in Conventional and Improved Turnout System
Jeon, Sang-Soo ; Eum, Ki-Young ; Kim, Jae-Min ;
Journal of the Korean society for railway, volume 10, issue 5, 2007, Pages 582~588
Since the turnout system in railroad restricts the train speed, the KNR (Korean National Railroad) provides the specification for the speed (130km/h) of the train when the train passes the turnout system. Therefore, the turnout system in pre-existing railroad is necessary to be improved to speed-up for the train. In this study, the dynamic wheel-load field tests have been performed to evaluate the track performance and the roadbed bearing capacity has been examined using numerical analysis at the turnout crossing in the conventional and improved turnout system. The impact factor is estimated using the data sets achieved from the dynamic wheel-load field tests in the conventional and improved turnout system. The stress acting on the roadbed for the improved turnout system is substantially decreased compare to that for the conventional turnout system.
Radio coverage prediction of RF-CBTC system under transmission power 10mW/MHz at K-AGT test line
Cho, Bong-Kwan ; Jung, Jae-Il ;
Journal of the Korean society for railway, volume 10, issue 5, 2007, Pages 589~595
Korea Railroad Research Institute has developed the driverless rubber-tired K-AGT (Korean-Automated Guideway Transit) system from 1999 to 2005 and has done its performance and reliability tests on the test line at Gyeongsan-city. Radio Frequency Communication-Based Train Control system of K-AGT, which employed Advanced Automated Train Control scheme, detects train position using the radio propagation delay between wayside and vehicle radio equipment. In this paper, we investigate whether the transmission power of radio system can be reduced to the permitted level announced by the Ministry of Information and Communication for license-free ISM(Industrial Scientific Medical) frequency bands. We first determine radio propagation model, using the measured data at test line, and perform simulation for radio coverage prediction. From the simulation results, we identify that the radio system operated with reduced power can provide good link quality in total test line.
Comparative LCA of three types of Interior Panel (IP) in Electric Motor Unit (EMU)
Choi, Yo-Han ; Lee, Sang-Yong ; Kim, Yong-Ki ; Lee, Kun-Mo ;
Journal of the Korean society for railway, volume 10, issue 5, 2007, Pages 596~599
A comparative Life Cycle Assessment (LCA) among three types of Electric Motor Unit (EMU) Interior Panel (IP) was conducted. A functional unit for comparative LCA is a weight of IP for 1 EMU. It is assumed that Manufacturing stage and its upstream processes, Use stage and End of Life (EoL) stage are included in the boundary of product system. For Use stage, the weight of IP causes electricity consumption. It is assumed that aluminum IP is recycled and the other IPs are incinerated at the EoL stage. As a comparison results, aluminum IP has much larger environmental impact (5.162pt) than others (FRP IP; 4.069pt, Phenol IP; 4.053pt) even though recycling consideration is included. The manufacturing stage of aluminum IP has relative big environmental impact (1.824pt) and this point make the most important difference from other IPs (FRP IP; 0.1617pt, Phenol IP; 0.4534pt)). Despite of large weight difference between FRP IP (888.96kg) and phenol IP (316kg), the final environmental impact result has only little difference (0.016pt, 0.39%). With this result, the EMU designer can choose IP with a consideration of the environmental performance of IP.
Static and Free Vibration Analyses of Hybrid Girders by the Equivalent Beam Theory
Choi, In-Sik ; Ye, In-Ho ;
Journal of the Korean society for railway, volume 10, issue 5, 2007, Pages 600~606
3D finite element analyses of a corrugated steel web girder and a steel truss web girder are conducted to investigate the static and dynamic behaviour of the hybrid girders. And the analyses results are compared with those by the equivalent beam theory. The equivalent theory is a theory that all section properties of a truss structure are replaced by section properties of a beam including a shear coefficient. When applying the equivalent beam theory, the shear coefficient of the corrugated steel web girder is estimated as the area ratio of flange section to web section and that of the steel truss web girder is calculated by the equation proposed by Abdel. Static deflections and natural frequencies by 3D finite element analyses and those by the equivalent beam theory are in good agreement.
A Study of Rail Wear by Change of Acceleration and Deceleration
Ha, Kwan-Yong ; Kim, Hie-Sik ;
Journal of the Korean society for railway, volume 10, issue 5, 2007, Pages 607~612
In this paper, operation mode of train was divided into powering, coasting, and braking and rail wear phenomenon has been done comparative analysis by each section. Data of train velocity is transferred to acceleration and deceleration from ATO Logging data. Amount of rail wear has been done comparative analysis by traction force of acceleration and braking force of deceleration and a plan for management of track irregularity is come up with by the result of the analysis.
A Study on the Curving Performance of a Scaled Bogie on a Scaled Curve Track
Hur, Hyun-Moo ; Park, Joon-Hyuk ; You, Won-Hee ; Park, Tae-Won ;
Journal of the Korean society for railway, volume 10, issue 5, 2007, Pages 613~618
The performance of the railway bogie is classified into the stability and the steering performance. Testing for the bogie stability is conducted on the roller rig, but testing for the bogie steering performance on test facility is very difficult, so the testing for the vehicle curving performance is conducted on the real curve track. Testing the railway bogie on the full scale test rig is desirable, but it caused many problems relating to test costs and test time. As a possible alternative to overcome these problems, a small scaled test rig is actively used in the field of bogie stability. Thus, in this paper, we have studied a scaled track to test the bogie steering performance. For this purpose, we designed the 1/5 scaled test track equivalent to radius 200 curve and confirmed the validity of the testing for the bogie steering performance on the sealed curve track through the testing using 1/5 scaled bogie.
The Evaluation for Running Safety of Incheon International Airport Railway EMU
Hong, Yong-Ki ; You, Won-Hee ; Lee, Hi-Sung ;
Journal of the Korean society for railway, volume 10, issue 5, 2007, Pages 619~625
The dynamic characteristic test result of electric rail car which is operated in Incheon International Airport Railroad is described in this paper. Express train in Incheon International Airport Railroad drives at 120km/h first in the country and derailment coefficient was measured for empty car and full-loaded car respectively. The measurement result of derailment coefficient, a key safety indicator about derailment, of empty car was higher than full-loaded car and both were lower than 0.8. The railway state wasn't good in operated section where is serviced about 80eh and derailment coefficient also increased. Horizontal pressure was below 2.1 ton at empty car and below 2.4 ton at full-loaded car. The electric rail car in Incheon International Airport Railroad has been confirmed it's running safety at 120km/h by the measurement of derailment coefficient. But the way of assessing applied in this paper has demerits such as complication of test method, difficulty for measurement device installation and high cost. Therefore the method which is simple to measure and can certify vehicle's safety even when service driving has to be researched.
A study on the parameters to enhance derailment safety
Hwang, Jeong-Taek ; Lee, Hi-Sung ;
Journal of the Korean society for railway, volume 10, issue 5, 2007, Pages 626~631
Technical requirements associated with derailment to ensure running safety of train are discussed. By using estimated derailment coefficient ratio, interaction of various parameters such as operation velocity, curve radius, cant, track irregularity, suspension stiffness and static wheel load ratio are analyzed to enhance derailment safety. Sensitivity analysis in terms of pattern and passage speed of curve is performed by using rolling stock and track conditions associated with SMRT Line No. 5.