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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 16, Issue 6 - Dec 2013
Volume 16, Issue 5 - Oct 2013
Volume 16, Issue 4 - Aug 2013
Volume 16, Issue 3 - Jun 2013
Volume 16, Issue 2 - Apr 2013
Volume 16, Issue 1 - Feb 2013
Selecting the target year
A Study for the Development of the Reliability/Availability Management System of the Urban Transit Vehicles (I)
Park, Kee-Jun ; Chung, Jong Duk ;
Journal of the Korean Society for Railway, volume 16, issue 3, 2013, Pages 163~168
DOI : 10.7782/JKSR.2013.16.3.163
The maintenance of an urban transit vehicle accounts for 60-70% of total costs over its entire life cycle, so it is critical to reduce maintenance costs and extend the life times of urban transit EMUs (electric multiple units) through research. For these researches, the reliability and availability data management system was constructed through the case study of several industries in the domestic and international in the field of reliability centered maintenance system. And we created a system to manage reliability and availability data for use in urban-EMU maintenance. In this work, we identified the major functions needed to successfully develop the system. Here we report the successful development of a reliability and availability data management system for maintenance of urban transit vehicles.
Aerodynamic Drag Reduction on High-performance EMU Train by Streamlined Shape Modification
Kwon, Hyeok-Bin ; Hong, Jai-Sung ;
Journal of the Korean Society for Railway, volume 16, issue 3, 2013, Pages 169~174
DOI : 10.7782/JKSR.2013.16.3.169
The effect of modifying the shape of a high-performance EMU train on the aerodynamic drag is studied here using Computational Fluid Dynamics(CFD) based on three dimensional Steady-state Navier-Stokes equation and two equation turbulence modeling. FLUENT 12 and Gambit 2.4.6 are employed for a numerical simulation of the aerodynamic drag of a streamlined-shape train as well as a proto type train. The characteristics of the aerodynamic drag of trains in tunnels are analyzed in a comparison with these characteristics in an open space. The contribution of the aerodynamic drag of each case is also investigated to establish principal pertaining to drag reduction for urban trains in tunnels. The aerodynamic drag of a streamlined train was reduced to 9.8% relative to a proto-type train with a blunt nose and a protruding roof facility and underbody shape: the running resistance is expected to be reduced by as much as 4% at a running speed of 80km/h.
Study on the Rolling Noise Model Using an Analysis of Wheel and Rail Vibration Characteristics
Jang, Seungho ; Ryue, Jungsoo ;
Journal of the Korean Society for Railway, volume 16, issue 3, 2013, Pages 175~182
DOI : 10.7782/JKSR.2013.16.3.175
Rolling noise is an important source of noise from railways; it is caused by wheel and rail vibrations induced by acoustic roughness at the wheel/rail contact. To reduce rolling noise, it is necessary to have a reliable prediction model that can be used to investigate the effects of various parameters related to the rolling noise. This paper deals with modeling rolling noise from wheel and rail vibrations. In this study, the track is modeled as a discretely supported beam by regarding concrete slab tracks, and the wheel vibration is simulated by using the finite element method. The vertical and lateral wheel/rail contact forces are modeled using the linearized Hertzian contact theory, and then the vibration responses of the wheel and rail are calculated to predict the radiated noise. To validate the proposed model, a field measurement was carried out for a test vehicle. It was found that the predicted result agrees well with the measured one, showing similar behavior in the frequency range between 200 and 4000 Hz where the rolling noise is prominent.
A Study on Reliability Centered Rolling Stock Maintenance Methods
Yu, Yang-Ha ; Lee, Nak-Young ;
Journal of the Korean Society for Railway, volume 16, issue 3, 2013, Pages 183~188
DOI : 10.7782/JKSR.2013.16.3.183
The purpose of maintaining rolling stock is to perform train service without failure during operation. It is not possible to prevent failure, however, by using periodic preventive maintenance methods, because new rolling stock is made from many electric components and requires the application of IT skills. RAMS (Reliability, Availability, Maintainability, Safety) methods have consequently been applied to new manufactured rolling stock in KORAIL since implementation of the KTX. With this approach it is possible to verify the reliability at the operating stage, and RCM (Reliability Centered Maintenance) methods for maintenance have been applied to manufactured rolling stock since the beginning of KTX service. A RCRM (Reliability Centered Rolling-stocks Maintenance) system suitable for the characteristics of rolling stock and operational factors is introduced in this paper.
A Study on the Implementation of an All-IP Train Communication Network Using Plastic Optical Fiber
Kim, Dongha ; Lee, Soyoung ; Choi, Kyuhyong ;
Journal of the Korean Society for Railway, volume 16, issue 3, 2013, Pages 189~195
DOI : 10.7782/JKSR.2013.16.3.189
Recent trains have broadband train communication networks to improve train operation safety and to provide passengers with multimedia services. Compared to glass optical fiber, plastic optical fiber (POF) has a large diameter; it also provides the good durability and maintainability necessary to railway applications. This paper suggests an All-IP broadband train communication network that connects all devices in the train through a POF interface. Performance tests according to Korean railroad standards shows that this POF interface is usable in the range of vibration and temperature conditions encountered in trains. A dedicated Layer-2 switch with the POF interface is developed for the construction of the All-IP train communication network. A prototype 1Gbps train communication network was set up in a trial-run of train on a metro line using the developed Layer-2 switch and POF. On-track tests indicated the feasibility of the POF train communication network. POF has an additional advantage of economic feasibility, and it is expected to start a trend toward broadband train communication networks using POF.
Optimal Sampling Method of Censored Data for Optimizing Preventive Maintenance
Lee, In-Hyun ; Oh, Sea-Hwa ; Li, Chang-Long ; Yang, Dong-In ; Lee, Key-Seo ;
Journal of the Korean Society for Railway, volume 16, issue 3, 2013, Pages 196~201
DOI : 10.7782/JKSR.2013.16.3.196
As there is no failure data for the entire lifecycle of a product, when analyzing reliability measures based on early failure data only, there may be a significant error between the estimated mean life and the real one, because it can be underestimated, or on the other hand, it can be overestimated when analyzing reliability measures based on a large amount of censored data with the failure data. To resolve the issue, this study proposes an optimal sampling estimation procedure that selects the proportion of censored data to estimate the optimal distribution with the idea that the estimated distribution could be approximated as closely as the real life distribution. This would work if we sampled the optimal proportion on the censored data, because failure data has real intrinsic distribution in any situation. We validate the proposed procedure using an actual example. If the proposed method is applied to the maintenance policy of TWC (Train to Wayside Communication) system, then we can establish the optimal maintenance policy. Thus, we expect that it will be effective for improvement of reliability and cost savings.
Simplified Collision Analysis Method for Submerged Floating Railway Using the Theory of a Beam with an Elastic Foundation
Seo, Sung-Il ; Kim, Jin Sung ;
Journal of the Korean Society for Railway, volume 16, issue 3, 2013, Pages 202~206
DOI : 10.7782/JKSR.2013.16.3.202
A submerged floating railway is an innovative tunnel infrastructure passing through the deep sea independent of wave and wind so that high speed trains can run on it. It doesn`t depend on water depth and is cost effective due to modular construction on land. The construction period can be reduced drastically. This paper introduces the concept design of a submerged floating railway, and for securing safety, proposes a method to analyze the structural behavior of the body in case of collision with a submarine. The theory of a beam with an elastic foundation was used to calculate the equivalent mass of the body so that the perfect elastic collision could be applied to calculate the collision velocity. The maximum deformation and bending moment was analyzed based on energy conservation. To verify the results, a collision analysis using a finite element analysis code was made. Comparing the results confirmed that this simplified collision analysis method gives enough accurate deformation and bending moment to be used for actual estimation in the initial design stage.
Experimental Study on Applying a Transition Track System to Improve Track Serviceability in Railway Bridge Deck Ends
Lim, Jongil ; Song, Sunok ; Choi, Jungyoul ; Park, Yonggul ;
Journal of the Korean Society for Railway, volume 16, issue 3, 2013, Pages 207~216
DOI : 10.7782/JKSR.2013.16.3.207
The components of concrete track (rail and rail fastening system) in railway bridge deck ends are damaged and deteriorated by track-bridge interaction forces such as uplift forces and compression forces owing to their structural flexural characteristics (bridge end rotation). This had led to demand for alternatives to improve structural safety and serviceability. In this study, the authors aim to develop a transition track to enhance the long term workability and durability of concrete track components in railway bridge deck ends and thereby improve the performance of concrete track. A time-history analysis and a three-dimensional finite element method analysis were performed to consider the train speed and the effect of multiple train loads and the results were compared with the performance requirements and German standard for transition track. Furthermore, two specimens, a normal concrete track and a transition track, were fabricated to evaluate the effects of application of the developed transition track, and static tests were conducted. From the results, the track-bridge interaction force acting on the track components (rail displacement, rail stress, and clip stress) of the railway bridge deck end were significantly reduced with use of the developed transition track compared with the non-transition track specimen.
Experimental Study on Characteristics of Deformation for Concrete Track on Railway Bridge Deck End induced by Bridge End Rotation
Lim, Jongil ; Song, Sunok ; Choi, Jungyoul ; Park, Yonggul ;
Journal of the Korean Society for Railway, volume 16, issue 3, 2013, Pages 217~225
DOI : 10.7782/JKSR.2013.16.3.217
In this study, by considering the rail fastening support distance and the distance between the bridge and the abutment, the behavior of concrete track installed on a railway bridge end deck and the bridge end rotation were analyzed. In order to analyze the track-bridge interaction, bridge and abutment specimens with concrete track structures were designed and used in laboratory testing. At a constant fastening support distance, an increase in the bridge end rotation caused an increase in the displacement of the rail. Therefore, the displacement of the rail directly affects the rail and clip stress. Further, it is inferred that the results of multiple regression analysis obtained using measured data such as angle of bridge end rotation and fastening support distance can be used to predict the track-bridge interaction forces acting on concrete track installed on railway bridge deck ends.
Analysis of the Economic Feasibility of a Monorail on Mt. Bomun on Daejeon
Kim, Myungsoo ;
Journal of the Korean Society for Railway, volume 16, issue 3, 2013, Pages 226~232
DOI : 10.7782/JKSR.2013.16.3.226
Recently, CO2 reduction policies are being promoted as parts of ESSD(Environmentally Sound and Sustainable Development), and many local governments are interested in monorails as a new means of transport. Here we report on a feasibility study for introducing a monorail system by considering the travel demands in the Mt. Bomun area in Daejeon, based on the area`s population. The feasibility of a monorail system on Mt.Bomun varies with respect to the demographic scale, mode shares, and operational distances. The strategies introduced here will help identify any tourist spots where local governments are trying to introduce monorail systems as a new system of transit.
A Study on Job Stress-Coping Plans for Urban Railroad Drivers
Park, Taesoo ; Lee, Jinsun ; Kim, Hongki ;
Journal of the Korean Society for Railway, volume 16, issue 3, 2013, Pages 233~239
DOI : 10.7782/JKSR.2013.16.3.233
This paper studied the stress of Metropolitan Transit driving crews. Stress to such workers can not only lead to fatalities and infrastructure damage but also enormous loss of competitiveness. The study was carried out to search for ways of alleviating stress of driving crews. In order to reduce the various factors that exacerbate job stress of driving crews of Metropolitan Transit, it is first necessary to expand training in order to enhance their expertise, and improve facilities to protect driving crews in the event of accidents. Second, psychological compensation or organization`s systems may cause job stress. It may therefore be possible to solve fundamental problems through typical organization level approach such as leadership training programs. Third, job stress may be reduced through proper life habits such as personal regular exercise. Fourth, we need to improve driving crews` working conditions and adjust working hours by avoiding excessive performance competition and an unfair evaluation system, by understanding their mental states, and by setting up systems such as a comprehensive health improvement and management program at the organization level.