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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 7, Issue 4 - Dec 2004
Volume 7, Issue 3 - Sep 2004
Volume 7, Issue 2 - Jun 2004
Volume 7, Issue 1 - Mar 2004
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A Study of Analysis Method for the Track Geometry Measuring Data on High Speed Railway
Journal of the Korean Society for Railway, volume 7, issue 4, 2004, Pages 291~295
The Track geometry measuring on High-speed railway is the most important subject for the track construction and track maintenance work. Also the measuring accuracy is so significant part because it provides principle data for the maintenance plan and the assesment of working quality and can control the train speed limitation. From this point of view, it is very important to verify for the track recording coach(EM120) in KNR. According to the result of spectrum analysis, the noise near 1m waveband was found on the track recording data from EM120. So, New filter has been applied to remove the noise form track recording data. and it makes possible to acquire resembling result to real track geometry.
Analysis for Frame Error Rate of a Data Transmission Protocol between CTC and SCADA
Journal of the Korean Society for Railway, volume 7, issue 4, 2004, Pages 296~301
This paper addresses an analysis for a railway data transmission protocol-Ethernet based data transmission between the CTC(Centralized Traffic Control System) and the SCADA(Supervisory Control and Data Acquisition) system. Fame error rates of the data transmissions are calculated and compared for the two cases that the CTC/SCADA has an extra data transmission error control(CRCI6) besides the inherent error control of the Ethernet(CRC32), and that the CTC/SCADA has no extra data transmission error control. With simulation results it has been verified that the extra data transmission error control(CRC16) contributes to lowering the frame error rate.
Application of Probabilistic Technique for the Development of Fire Accident Scenarios in Railway Tunnel
Journal of the Korean Society for Railway, volume 7, issue 4, 2004, Pages 302~306
Many long railway tunnels without emergency evacuation system or ventilation system are under construction or in-use in Korea. In the case of tunnel-fire, many fatalities are occur in current condition. Current safety level is estimated in this study, for the efficient investment on safety. But so many uncertainties in major input parameters make the safety estimation difficult. In this study, probabilistic techniques are applied for the consideration of uncertainties in major input parameters. As results of this study, accident scenarios and survival ratio under tunnel fire accident are determined for various conditions.
A Study on the Deterioration Progress of Railway Arresters
Journal of the Korean Society for Railway, volume 7, issue 4, 2004, Pages 307~311
Arresters are the best protective device on electrical power systems against transient overvoltages generated by lightning and/or switching operation. Nonetheless, arresters are deteriorated by absorption of moisture in the environments of its use, repetition in the protective operation to overvoltages, and some defects at manufacturing. It is therefore important to estimate the electrical characteristic changes of ZnO blocks. In this paper, an accelerated ageing test by a standard lightning impulse current was carried out to extract parameters needed for arrester diagnosis, and leakage current components were measured. Total energy applied to the ZnO blocks at each time is about 1,050[J] in 8/20[
] impulse current. From the experimental results, we proposed electrical parameters and leakage current level to diagnose arrester soundness.
Parametric Analysis on Construction Conditions to Control Thermal Cracks in Subway Concrete Structure
Journal of the Korean Society for Railway, volume 7, issue 4, 2004, Pages 312~318
The wall in a subway structure is easily subject to crack occurrence since its expansion and shrinkage associated with hydration heat reaction is constrained by the slab. The greater problem is that the crack in the wall may be developed to pass through thickness and eventually deteriorate the structure due to rusting of reinforced steel. Thus, this study aims at controlling thermal cracks as much as possible and determining an optimized size of concrete placement through hydration heat analysis. For this study, effects of placement height, length, temperature and types of cement on the thermal cracks were evaluated by temperature rise, thermal stress and crack index. As results of parametric study, it was found that placement height and length do not have an effect on the temperature rise but have significant one on thermal stress which relates to direct possibility of thermal crack occurrence. This means that proper selection of size balancing internal constraint with external one is much more important than reducing the placement height and length simply. In order to prevent from thermal cracks most effectively, in addition, it was noted to reduce placement temperature and to use the cement blended with mineral admixture.
Analysis and Design Programming of RC Beams Strengthened with Carbon Fiber Sheets
Journal of the Korean Society for Railway, volume 7, issue 4, 2004, Pages 319~325
In this study, analysis and design programs of bending of RC beams strengthened with fiber sheets are developed by using Visual Basic Language. The program consists two groups, ultimate strength method and nonlinear flexural analysis method. Ultimate strength method regards concrete compressive stress as a rectangular stress block and do not consider tensile stress of concrete and load-deflection curves. On the other hand, nonlinear flexural analysis considers tensile stress of concrete, load-deflection curves, state of stress distribution and failure strain of strengthening material. Also, the analysis method used in this study regards nonlinear flexural stress as compressive stress of concrete. This program can be a good tool for determining the bending strength of strengthened RC beams and estimating the amount of fiber sheets for practical use.
An Enumeration Algorithm for Generating the Candidate Routings in a Set Partitioning Problem Approach to the Rolling Stock Requirement Plan
Journal of the Korean Society for Railway, volume 7, issue 4, 2004, Pages 326~331
A routing is the path that an actual trainset follows as it moves from one train to another train in a timetable. The number of routings is equivalent to the number of trainsets required to cover the timetable. The primary factors of rolling stock requirement plan include evaluating the minimum number of routings. This can be formulated as a set partitioning problem and solved using enumeration method or column generation method. In this paper we presents an enumeration algorithm which is useful to implement the enumeration method for the rolling stock requirement plan.
Analysis and Evaluation of Ride Comfort for High Speed Train using Statistical Method according to UIC 513R
Journal of the Korean Society for Railway, volume 7, issue 4, 2004, Pages 332~338
The two projects about the high speed train have been performed in Korea, one project is the commercial run of high speed train(KTX) from Seoul to Busan and the other is the development of original high speed train(HSR 350x). As the successful results, the service run of KTX had been launched on the 1st of April, 2004 and HSR 350x had been fabricated in June, 2002 and has been tested in the Kyoungbu line and Honam line since then. The railway has the track irregularities which cause vibrations, such as rail joints, turnout, level crossing, transition curves and super-elevation ramps, and variations in the track level(z-axis) and the gauge(y-axis). Generally, the ride comfort for railway is evaluated by using the vibrations. In this paper, the ride comfort indices according to mc 513R and ISO 10056 have been reviewed when the high-speed trains are operated on both Kyoungbu line and Honam line. Also, the ride characteristics for KTX and HSR 350x on the high speed line and the conventional line have been analyzed and evaluated. The results show that the high-speed train has no problem from the viewpoint of the comfort ride on the high speed line and the conventional line and the ride index for HSR 350x is same as that for KTX in the high speed(300 km/h).
A Hybrid Active Power Filter for Electric-Railway Systems Using Multi-Level Inverters
Journal of the Korean Society for Railway, volume 7, issue 4, 2004, Pages 339~344
This paper proposes transformerless power conversion system consisting of a single-phase diode rectifier and a shunt hybrid filter for the electric-railway system. The hybrid filter consists of a single tuned LC filter per a phase and a low-rated NPC type multi-level inverter. Compared with conventional active filters. transformers are not used. Also, LC filter works as not only a harmonic filter tuned at the 3rd harmonic frequency but also a switching-ripple filter. The rating of the active filter can be decreased by using a NPC type multi-level inverter. The simulation results confirm the validity of the system.
A study on the fatigue life and the change of the strain during the fatigue fracture on the fillet welded specimens of SM490A
Journal of the Korean Society for Railway, volume 7, issue 4, 2004, Pages 345~349
This study investigates the fatigue lives of SM490A material(base metal) specimens and fillet weld specimens, which are made same material and weld method for the railway vehicle. These fatigue lives have a difference, the fatigue lives of weld specimen are shorter than those of base metal. We measured the strains on the weld positions of the specimens during the fatigue test for investigation of crack initiation and crack growth. In these result, we could find the information of the crack initiation position on weld bead and the history of crack growth. Also we knew that the fatigue crack initiation cycles and the changes of the strain which were affected the fractured surface roughness and morphology.
A Study on the Duty Hour Structure for Railway Crews
Journal of the Korean Society for Railway, volume 7, issue 4, 2004, Pages 350~355
Because the wage of railway crews is based on the duty hour rather than the working hour, most researches have focused on the balance of duty hour for the crews. In this paper, the structure of duty hour and its relationship to the crew wage are analyzed and some issues are identified. The duty hour consists of several different jobs which are weighed equally in calculating the crew's wage. Also, the difference between the working hour and duty hour is inconsistent with the train routes; i.e., the difference of a long distance train is larger than that of a small or medium distance train. To solve the problems, possible ways to link the duty hour to the wage better are proposed and exemplified
Reliability Analysis of Auxiliary Power System on Korea High Speed Train
Journal of the Korean Society for Railway, volume 7, issue 4, 2004, Pages 356~359
In this paper, as the first step to assess and enhance the reliability of Korea High Speed Train, auxiliary power system is selected and reliability analysis is carried out. The auxiliary power system is classified into subsystems and functional analysis is conducted. Reliability block diagrams are drawn and reliability parametric analysis is performed. Analysis results show that the reliability of auxiliary power system depends on critical items. To grow the system reliability, activities should be concentrated on improvement of critical items.
Evaluation of Tilting Trains Speed in Conventional Railways Curves Considering Passenger′s Comfort in Transition Area
Journal of the Korean Society for Railway, volume 7, issue 4, 2004, Pages 360~366
The purpose of this paper is to present the alignment layout and the way of modifying transition curve for better operation of tilting trains. It is based on data from field investigation of all curves in conventional line. In general, all curves have transition parts in the beginning and end of the main curve in order to improve the passenger's comfort. The speed-up of conventional line may need an extention of transition curves. This paper checked out whether the transition curve should be modified or not and how to lengthen it. Then the maximum train speeds in curve prior to and after the modification of transition curve were evaluated.
Evaluation of Running Stability of Tilting Trains in Conventional Curved Track
Journal of the Korean Society for Railway, volume 7, issue 4, 2004, Pages 367~373
The investigation of running stability of the train for curved track is necessary in view of preventing the train from derailment caused by unbalanced forces transferred from the wheel and guaranteeing moderate level of running safety in curve sections. This paper carried out an analysis of running stability of tilting trains in conventional line which the test operation of tilting trains under development are scheduled. For this purpose, the wheel load and lateral pressure to the rail are evaluated. The criteria for the calculated wheel load and derailment coefficient are compared to the design criteria for running stability. It is founded that the running stability of tilting trains for curved track is guaranteed to have sufficient safety and the train speed in curve is governed by the geometric layout of track rather than the criteria for running stability.
The Basic Study on the development of rail industry
Journal of the Korean Society for Railway, volume 7, issue 4, 2004, Pages 374~390
In this paper, I illustrate the situations and problems rail industry is faced with. The rail industry has been suffering deficiency in investment with low technical level. Lacks of strategic marketing plans and low competitiveness in the industry led to a small portion of modal share, estimated at 12.6% in 2001(person base). Recently, rail industry has caught up with the current flow of changes. For example, a prototype of Korea high speed train had been manufactured to be successfully tested on commercial track. And the amount of rail investment increased gradually. The rail industry of EU nations, America, Japan reveals good outcomes, which keeps the balance in the black thanks to growth of investment in rail and high technical level. I have come up with some ideas for improvement, which I believe will be helpful to lead the rail industry. First, I suggest the upbringing of rail industry and technology on a national level. Second, expanding the rail network with the rail modernization. Lastly, I think it is crucial to establish a law and institution before we advance into overseas markets.
Analytical Study for dispersed Phase Velocity Information of Love Waves
Journal of the Korean Society for Railway, volume 7, issue 4, 2004, Pages 391~399
This paper investigated the dispersion characteristics of horizontal surface waves as means to apply conversional SASW techniques. To verify this proposal, 3D finite element analysis and Transfer matrix solution were performed. SH wave(Love waves) has the some advantages in comparison with Rayleigh wave. Representatively, Love wave has a characteristics not affected by compression wave. These characteristics have the robust applicability for the surface wave investigation techniques. In this study, for the purpose of employing Love wave in the SASW method, the dispersion characteristics of the Love wave was extensively investigated by the theoretical and numerical approaches. The 3-D finite element and transfer matrix analyses for the half space and two-layer systems were performed to determine the phase velocities from Love wave as well as from both the vertical and the horizontal components of Rayleigh wave. Preliminary, numerical simulations and theoretical solutions indicated that the dispersion characteristics of horizontal surface wave(Love waves) can be sufficiently sensitive and appliable to SASW techniques.
On the Performance of STBC/Beamforming Systems for High Speed Trains
Journal of the Korean Society for Railway, volume 7, issue 4, 2004, Pages 400~405
Recently, MIMO communications are regarded as one of the most promising emerging wireless technologies. This paper investigates MIMO wireless systems and their applications in a railway communication system. We firstly discuss railway communication environments including propagation characteristics and radio channel modeling. Next, we consider channel estimate methods, which is a crucial issue under rapidly varying channel condition due to the movement of trains. Channel estimation methods for MIMO systems are addressed and the effect of estimation error is studied. We also have performed simulations for transmit beamforming system and STBC(Space-time block coding) to investigate the performance of MIMO schemes in railway systems.
Development of BOM System Using Component Based of Urban Transit
Journal of the Korean Society for Railway, volume 7, issue 4, 2004, Pages 406~411
BOM(Bill of Materials) is a listing or description of raw materials, parts, and assemblies that define a product. In order to evaluate the performance of proposed BOM management system, which is very important to maintenance information system of urban transit. We develop component based BOM data and rule-set to design data structure that is mutually independent and integrated efficiently. It divides data whit management interface using component technology. The component based master BOM have advantage in database size and flexibility. Flexibility is measured as the number of updating records in accordance with added new product or engineering change. In database size, component based BOM is the best. we develop master BOM management system in web environment.
Ground fault protective relaying schemes for DC traction power supply system
Journal of the Korean Society for Railway, volume 7, issue 4, 2004, Pages 412~417
In urban rail transit systems, ground faults in the DC traction power supply system are currently detected by the potential relay, 64P. Though it detects the fault it cannot identify the faulted region and therefore the faulted region could not be isolated properly. Therefore it could cause a power loss of the trains running on the healthy regions and the safety of the passengers in the trains could be affected adversely. Two new ground fault protective relay schemes that can identify the faulted region are presented in this paper. A current limiting device, called Device X, is newly introduced in both system, which enables large amount of ground fault current flow upon the positive line to ground fault. One type of the relaying schemes is called directional and differential ground fault protective relay which uses the current differential scheme in detecting the fault and uses the permissive signal from neighboring substation to identify the faulted region correctly. The other is called ground over current protective relay. It is similar to the ordinary over current relay but it measures the ground current at the device X not at the power feeding line, and it compares the current variation value to the ground current in Device X to identify the correct faulted line. Though both type of the relays have pros and cons and can identify the faulted region correctly, the ground over current protective relaying scheme has more advantages than the other.