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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 18, Issue 6 - Dec 2015
Volume 18, Issue 5 - Oct 2015
Volume 18, Issue 4 - Aug 2015
Volume 18, Issue 3 - Jun 2015
Volume 18, Issue 2 - Apr 2015
Volume 18, Issue 1 - Feb 2015
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Study on the Levitation Stability of Maglev Vehicle considering the Vibration of Steel Switch Track
Han, Jong-Boo ; Park, Jinwoo ; Han, Hyung-Suk ; Lee, Jong-Min ; Kim, Sung-Soo ;
Journal of the Korean Society for Railway, volume 18, issue 3, 2015, Pages 175~185
DOI : 10.7782/JKSR.2015.18.3.175
Generally, in the train area, switch tracks have required high reliability because this system is directly associated with derailment. Especially, switch tracks of Maglev vehicles must be moved in terms of the whole geometric characteristics, in which the bogies are encased in the switch track. For this reason, switch track was constructed with steel lighter than concrete girders. But, the steel switch track was weak because of structural vibration as well as structural deformation. Therefore, it is important to predict the levitation stability when a vehicle passes over flexible switch track. The aims of this paper are to develop a coupled dynamic model to describe the relationship between a Maglev vehicle and switch track and to predict the levitation stability. In order to develop the coupled dynamic model, a three dimensional vehicle model was developed based on multibody dynamics; a switch model was made using the modal superposition method. And, the developed model was verified using comparison measured data.
Reliability Growth Analysis for Next-Generation High-speed Train
Noh, Hee-Min ; Kim, Seog-Won ;
Journal of the Korean Society for Railway, volume 18, issue 3, 2015, Pages 186~193
DOI : 10.7782/JKSR.2015.18.3.186
In this paper, a reliability growth analysis for a next-generation high-speed train was conducted. First, the high-speed train was decomposed into 6 sub-systems and main equipment of the high-speed train was derived from functional diagrams. Next, failure rates were calculated for each sub-system from the failure data obtained during commissioning tests. Then, reliability growth analysis was conducted for the high-speed train using the Duane model. The results show that activities to increase reliability were carried out throughout the test runs from the reliability growth results.
Ride Quality Analysis Using Seated Human Vibration Modeling
Kang, Ju Seok ;
Journal of the Korean Society for Railway, volume 18, issue 3, 2015, Pages 194~202
DOI : 10.7782/JKSR.2015.18.3.194
In this paper, dynamic modeling with viscoelastic properties of a human body resting on a seat is presented to quantitatively analyze ride quality of passengers exposed to vertical vibrations. In describing the motions of a seated body, a 5 degree-of-freedom multibody model from the literature is investigated. The viscoelastic characteristics of seats used in railway vehicles are mathematically formulated with nonlinear stiffness characteristics and convolution integrals representing time delay terms. Transfer functions for the floor input are investigated and it is found that these are different in accordance with the input magnitude due to nonlinear characteristics of the seat. Measured floor input at the railway vehicle is used to analyze realistic human vibration characteristics. Frequency weighted RMS acceleration values are calculated and the effects of the seat design parameters on the frequency weighted RMS acceleration values are presented.
Comparison of Ride Comfort between Korean and European High Speed Railway by using Continuous Comfort Method
Choi, Il-Yoon ; Um, Ju-Hwan ; Lee, Jun Suk ; Choi, Min-Ji ; Lim, Jihoon ;
Journal of the Korean Society for Railway, volume 18, issue 3, 2015, Pages 203~211
DOI : 10.7782/JKSR.2015.18.3.203
Ride comfort of a vehicle can be utilized to maintain the track geometry and track irregularities because ride comfort of the rolling stock is affected by the characteristics of the vehicle and track. Ride comfort was evaluated according to the measured floor acceleration data of vehicles for a Korean high speed line as well as European high speed lines using Continuous comfort method which can be applied to track maintenance. The exceedance distribution of the ride comfort was quantitatively analyzed by the vehicle speed, the ride comfort of the Korean high speed line was compared with that of European high speed lines. It is shown that the ride comfort of Korean high speed line is better than that of European high speed lines, which indicates that the Korean track geometry and track irregularities are properly maintained.
Characteristics of Rolling Noise Sources of Tram Resilient Wheels and Track
Jang, Seungho ; Ryue, Jungsoo ;
Journal of the Korean Society for Railway, volume 18, issue 3, 2015, Pages 212~222
DOI : 10.7782/JKSR.2015.18.3.212
The characteristics of noise emission from tram systems should be investigated in order to design and construct an urban tram network that raises fewer environmental noise problems. In this paper, the characteristics of rolling noise from a tram were studied and a desired stiffness of the rail supports was proposed using a noise prediction model. The mobilities of embedded rails and resilient wheels were predicted using the Timoshenko beam model and the finite element model, respectively. The predicted mobilities were compared with the measured results. Compared with the measured values, the calculated noise level near the track showed small errors for frequencies higher than 300 Hz. Then, the source strengths of rail and wheel components were examined by varying the rail supporting stiffness and the slab supporting stiffness so that suitable stiffness values could be estimated that would reduce noise radiated from rails and wheels but that would not greatly increase the ground vibration.
Implementation of Mobile Hot-spot Network for Subway Wireless Backhaul Network
Kim, Dongha ; Kim, Ilgyu ; Choi, Kyuhyoung ;
Journal of the Korean Society for Railway, volume 18, issue 3, 2015, Pages 223~231
DOI : 10.7782/JKSR.2015.18.3.223
This paper proposes a new wireless backhaul technology based on MHN(Mobile Hotspot Network) which uses a wide frequency band of millimeter wave to provide wideband Wi-Fi services for subway passengers. Performance analysis of MHN up and down links, based on data: up and down links structure analysis of physical layer and simulation study of the MHN wireless backhaul link model, show that the proposed MHN-based wireless backhaul network can transmit data at a 1.2Gbps data rate and provide Internet service 100 times faster than that of conventional WiBro-based wireless backhaul networks. These results indicate that the proposed MHN technology is appropriate for subway mobile networks.
A Study on Interference between High Voltage Impulse Track Circuit(HVITC) and AF Track Circuit
Lee, Hee-Jin ; Lee, Jong-Woo ;
Journal of the Korean Society for Railway, volume 18, issue 3, 2015, Pages 232~240
DOI : 10.7782/JKSR.2015.18.3.232
Two types of track circuits are used in high speed railway car depots: one is High Voltage Impulse Track Circuit(HVITC); the other is AF track circuit. HVITC detects train occupation of blocks and broken rail; the AF track circuit is used for train onboard control system pretesting before departure. This testing is used to transmit train control information through the AF track circuit. The two systems are switched in turns for testing. We propose a system in which the AF track circuit is replaced by a loop cable that is installed on the inside rail; as such, engineers do not need to switch the systems. In cases in which the two systems run simultaneously, mutual interference may occur. In this paper, we identified this mutual interference by modeling of the two circuits.
Optimal Section of Ballasted Asphalt Track Considering Design Lifetime and Economic Feasibility
Lee, Seonghyeok ; Lee, Jinwook ; Lee, Hyunmin ;
Journal of the Korean Society for Railway, volume 18, issue 3, 2015, Pages 241~251
DOI : 10.7782/JKSR.2015.18.3.241
Compared with ballasted track (BT), ballasted asphalt track (BAT) has been increasingly adopted in many countries due to its more greatly reduced reinforced roadbed thickness and smaller cumulative plastic deformation, and its advantages in terms of maintenance. In this respect, the authors` previous research includes analysis of BAT sections that show performance similar to that of BT sections of the present specifications; reliability verification of the analysis results through real-sized static and dynamic train-load tests were performed. Based on previous research, this paper estimates the track lifetime using the strain of the lower roadbed according to reinforced roadbed thickness; using probabilistic LCC analysis, this paper presents a BAT section that satisfies the design lifetime and that has performance similar to or higher than that of BT.
Behavior Characteristics of Ballasted Track on Asphalt Roadbed Using Real Scale Test
Lee, Seonghyeok ; Lee, Jinwook ; Lee, Hyunmin ;
Journal of the Korean Society for Railway, volume 18, issue 3, 2015, Pages 252~260
DOI : 10.7782/JKSR.2015.18.3.252
Ballasted track on an asphalt roadbed can be beneficial for its various effects such as (i) decreasing of roadbed thickness by dispersing train load; (ii) prevention of both strength reduction and weakening in roadbed system by preventing rainwater penetration; and (iii) reducing maintenance cost by preventing roadbed mud-pumping and frostbite. With these beneficial effects, ballasted track on asphalt roadbed has been widely used in Europe and Japan, and relevant research for applying such ballasted track on asphalt roadbed systems in Korea is ongoing. In this study, full-scale static and dynamic train load tests were performed to compare the performance of ballasted track on asphalt roadbed and ballasted track. The optimum thickness levels of asphalt and reinforced roadbeds, corresponding to the design criteria for reinforced roadbed of high-speed railway, was estimated using the FEM program ABAQUS. Test results show that the earth pressure on reinforced roadbed of ballasted track on the asphalt roadbed was relatively low compared with that of simple ballasted track. The elastic and plastic displacements of simple ballasted track on the asphalt roadbed were also lower than those of ballasted track. These test results may indicate that the use of ballasted track on asphalt roadbed is an advantageous system in view of long-term maintenance.
Performance Test of Wall to Wall Modular Structure Joint for Near-surface Transit
Lee, Jong Soon ; Kim, Hee Sung ; Lee, Sung Hyung ; Lee, Jun Kyoung ;
Journal of the Korean Society for Railway, volume 18, issue 3, 2015, Pages 261~269
DOI : 10.7782/JKSR.2015.18.3.261
To overcome the weaknesses of viaduct bridges and the non-economic efficiency of underground LRT, the study of near-surface railway systems is in progress. To apply a box structure to the low depth transit, a connection joint to precast modules are very important when applying precast modular structures to replace temporary structures. In this study, wall to wall connections were applied in diverse cases such as rebar connections, guiding structures that were used to fit the verticality of precast walls during construction, and non-reinforcement structures used only for waterstop. Experimental performance verification was carried out for the bending, shear and splitting of the wall to wall connection. Precision of construction joints between wall to wall was identified as a factor that influenced the structural performance of the precast wall. A structure that can serve as a guide during the vertical insertion of a wall is confirmed for the most suitable case, but it will be necessary to modify this structure for detailed cases.
Development of an Algorithm for Estimating Subway Platform Congestion Using Public Transportation Card Data
Lee, Ho ; Choi, Jin-Kyung ;
Journal of the Korean Society for Railway, volume 18, issue 3, 2015, Pages 270~277
DOI : 10.7782/JKSR.2015.18.3.270
In some sections of the Seoul Metropolitan Subway, severe congestion can be observed during rush hours and on specific days. The subway operators have been conducting regular surveys to measure the level of congestion on trains: the results are then used to make plans for congestion reduction. However, the survey has so far focused just on train` congestion and has been unable to determine non-recurring congestion due to special events. This study develops an algorithm to estimate the platform congestion rate by time using individual public transportation card data. The algorithm is evaluated by comparison of the estimated congestion rate and the ground truth data that are actually observed at non-transfer subway stations on Seoul subway line 2. The error rates are within
and the performance of the algorithm is fairly good. However, varying walking times from gates to platforms, which are applied to both non-peak periods and peak time periods, are needed to improve the algorithm.