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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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Low-cost Single-Phase HAIf-bridge Active Power Filter with One Current Sensor
Journal of the Korean society for railway, volume 7, issue 3, 2004, Pages 173~179
This paper describes a low-cost single-phase active power filter, which consists of a half-bridge PWM inverter with a simple control circuit. In order to verify the performance of proposed active power filter, many computer simulations with EMTP codes and experimental works with a hardware prototype were done. Both results confirm that the proposed active power filter shows excellent performance to eliminate the harmonics generated in the single-phase non-linear load. The active power filter has advantage of low implementation cost and compact size, using a half-bridge inverter and a simple control circuit with only one current sensor. So, it can be fabricated as a plug-in type. This paper shows the necessity and a good possibility to apply such advantage to the electric railway system.
A Numerical Study of the Effect off Fire Growth Model on Fire Characteristics in a Carriage
Journal of the Korean society for railway, volume 7, issue 3, 2004, Pages 180~185
The present study investigates the effect of fire growth model on fire development characteristics in a carriage. The parallel processing version of FDS code is used to simulate the fire driven flow in a carriage and two types of fire growth model which are flame spread model and t
model are examined for the same geometrical condition. The heat release rates(HRR) of both model are similar each other until 30 s after ignition, but the flame spread model predicts 5 times higher than those of the t
fire model during the quasi-steady fire period. Maximum heat release rate in the case of flame spread model reaches about to 12 MW at 100 s after fire ignition. Also, various database of fire properties for combustible materials and more elaborate combustion model considering the flame spreading phenomena are required for better predictions of fire development characteristics using numerical simulation.
A Study on the Contact Behavior of Stress-Displacement Characteristics for an Inclined Rail-Wheel Contact Mode
Journal of the Korean society for railway, volume 7, issue 3, 2004, Pages 186~192
Using the finite element method, rail-wheel contact model has been analyzed for mechanical loads due to passengers and payload of the train. This paper presents an investigation on how tapered wheel and inclined rail surfaces affect the contact stress and displacement of rail-wheel contacting surface under mechanical loads. For a numerical analysis, the tapered faces of the wheel are considered as 2.5% and 5.5%. And two models of the tilted rail are also considered as 40：1 and 20：1 at the bottom of the rail. The computed results based on the contact stress and displacement FE analysis indicate that the tilting ratio of the rail, 20：1 with a tapered face of the wheel, 2.5% may be more stable compared to that of 40：1 tilting model and 5.5% tapered wheel face.
The Numerical Analysis off the Flow-field Around the Korean Tilting Train Express
Journal of the Korean society for railway, volume 7, issue 3, 2004, Pages 193~199
Numerical analysis of aerodynamic characteristics was differently performed according to the running situation of the Korean Tilting Train eXpress(TTX) that would be introduced for an improvement in efficiency of the used railroad track. Fluent 6.0 was used for the analysis of Non-tilting case, Tilting case and Passing-by case with the model of TTX. As a result, the aerodynamic drag had little difference between Tilting and Non-tilting case. However, pressure contour under the train of Tilting case was not symmetry because the gap between a train and the ground was different at both sides. In Passing-by case attraction and counterattraction occurred alternately and affected to the opposite train. When two trains were side by side, the maximum attraction was generated especially. Through an analysis of pressure wave in tunnel a large variation of pressure was generated by the bluff nose of TTX. The results in this study would be good data for the aerodynamic characteristic on TTX and provide important information to judgment of running safety.
Theoretical x-t Diagram Analysis on Pressure Waves of High Speed Train in Tunnel
Journal of the Korean society for railway, volume 7, issue 3, 2004, Pages 200~207
Theoretical study has been conducted to clarify pressure characteristics of KTX (Korea Train eXpress) in tunnel. The severe pressure change in tunnel may give rise to the ear-discomfort for passenger and fatigue for car body. Critical tunnel lengths which are induced by x-t diagram analysis can be applied to the experimental results measured by using the running test with atmospheric pressure sensors and portable data acquisition system in previous study. In this study, the tunnels from 200m to 4000m in length have been chosen for the investigation of tunnel length effects. We found that there are similar patterns of external pressure change for each critical tunnel length. The critical tunnel lengths are governed by train speed, train length and sonic velocity. And, the patterns of pressure wave in tunnel are classified into eight groups.
A Study on the Traction System and Electric Devices of Double Deck (Express) Trains
Journal of the Korean society for railway, volume 7, issue 3, 2004, Pages 208~214
In this paper, traction system and electric devices of a double deck train were designed to examine technical reasonableness for driving on the ground and underground. Double deck trains operated in other countries were also considered. For designing the electric devices, two types of accelerations and electric devices arrangements which are based on the current subway system were considered.
Development of VE/LCC Evaluation Model for Railway Route Selection
Journal of the Korean society for railway, volume 7, issue 3, 2004, Pages 215~222
Optimal route selection of railway should take consideration of the function of the railway, topography, practicability of construction and management as well as the cost. This study performed the surveys for experts and surrounding industries and the review for the bid guidelines in order to develop the quality model with the AHP method and establish the weight for each factor. Six quality models were developed for such as the efficiency of railway operation, structure design and practicability, economic feasibility, correspondence with other plans, civil appeal and environmental sustainability, and correspondence with system. The detailed evaluation elements were also derived by each factors.
Application of Personal Digital Assistant (PDA) for Mobile Bridge Management System (MBMS)
Journal of the Korean society for railway, volume 7, issue 3, 2004, Pages 223~231
The accumulated BMS data have made it easy to make reasonable decision-making for bride maintenance and repair work. In the developing period of BMS, the bridge management was not easy due to the lack of understanding of BMS and low credibility of the data. In recent years, it has been possible to enhance the credibility of the data and to expand the application scopes of BMS with the efforts of Local Road Construction Offices. The reasonable decision making for bridge management can improve the performance of bridges under the practical constraints such as limited budget. It can then result in the reduction of bridge maintenance budget. This study provides the methodology for the application of mobile internet-based KOBMS for bridge management. The data flow for BMS is the most important factor for decision-making on budget allocation, and this study establishes the basic scheme of the data flow for BMS. The implementation of PDA for BMS may suggest a new paradigm of 'Mobile' in the field of construction management.
Characteristics of Current Collection Signals during Test Run of High-speed Train
Journal of the Korean society for railway, volume 7, issue 3, 2004, Pages 232~238
The dynamic characteristics of the current collection process of the high-speed railway are investigated through signals acquired during a test run. The signals are obtained from accelerometers, load cells, and strain gauges attached to various positions of the pantograph, and they are processed in time-and frequency-domains to obtain the dynamic characteristics. The main natural frequency of the pantograph is found to be 8.5Hz. There also are components at low frequencies varying linearly with the train speed. The contact frequency components above 20Hz is attenuated as they pass through the secondary suspension. The main frequency component of the load cell signal is found to be related with the rolling motion of the panhead generated by the stagger in the catenary.
Spectral Element Analysis of an Axially Moving Thermoelastic Beam
Journal of the Korean society for railway, volume 7, issue 3, 2004, Pages 239~244
The use of frequency-dependent spectral element matrix (or exact dynamic stiffness matrix) in structural dynamics may provide very accurate solutions, together with drastically reducing the number of degrees of freedom to improve the computation efficiency and cost problems. Thus, this paper develops a spectral element model for the coupled thermoelastic beam which axially moves with constant speed under a uniform tension. The accuracy of the spectral element model is then evaluated by comparing the natural frequencies obtained by the present element model with those obtained by the conventional finite element model.
A Study on the Construction Methodology of Preventive Maintenance System for Urban Transit
Journal of the Korean society for railway, volume 7, issue 3, 2004, Pages 245~250
The safety of staff, customers and of general Public in general viewed as one of the most important requirements in the urban transit. The maintenance computerization system for car of urban transit is a part of standardization and development of urban transit system, and We have been performed the establishment of maintenance computerization system from 2001 to 2005. The RAMS (reliability, availability, maintainability and safety) estimation for maintenance computerization system are utilized in a variety of computerization system for user's convenience and safety in maintenance. Ever since its inception though, the urban transit has searched for ways to improve reliability, availability, maintainability and safety of the railway subsystem. Provision of a reliable maintenance system include RAMS of the vehicles plays a very important role in achieving a safe system.
A Case Study for Safety Analysis
Chang, Kwang-Chi ; Lee, Key-Seo ;
Journal of the Korean society for railway, volume 7, issue 3, 2004, Pages 251~258
A systematic methodology to determine safety requirements for railway signalling system and safety requirement allocation into system are presented. THR concept is used for as an interface between Risk Analysis to be performed by railway operator and System Design Analysis by the supplier. This approach is based on Signalling Safety Standard EN50129 by CENELEC.
Effects of Wheel Profile on KTX Dynamic Characteristics
Journal of the Korean society for railway, volume 7, issue 3, 2004, Pages 259~263
The running safety of a railway vehicle depends on the design parameters and contact condition between wheel and rail. In this study, the effect of the conicity of wheel tread is analyzed using ADAMS/RAIL software on running situation. Modal analysis shows in 0.6 Hz natural frequency of lateral mode in fully arranged the KTX cars. The excessive vibration of the tail cars occurs in the 17th car as the speed and the stiffness of the secondary suspension increases, and especially for 1/40 conicity of the GV40 wheel. Also, the analysis shows that combination of wheel profile, GV40 for power cars and XP55 for passenger cars can reduce the lateral vibration of the tail cars.
An Application and Evaluation of Hub-and-spoke Strategy for Rail Freight Service in European Networks
Journal of the Korean society for railway, volume 7, issue 3, 2004, Pages 264~270
The hub-and-spoke strategy is widely used in the field of transportation. At the field of rail transportation, however, it is difficult that we find an application case of this strategy because of modal characteristics. According to the fast growth of containerization and the development of transshipment technology, presently, the hub-and-spoke strategy is introduced by operators on actual European rail freight transportation. However, it is hardly to find empirical studies evaluating the applicability of transportation strategy. In this context, this study analyzed the applicabilities of hub-and-spoke strategy in the actual network of European rail freight. For the application and evaluation of the characteristics of hub-and-spoke strategy, it utilized a service network design model for rail freight. Utilizing this model, it analyzed the efficiency of furnished rail freight services, the potential locations of hubs, the characteristics of O-D flows by the types of trains and service links, and the types of paths of O-D flows. Finally, it proposed some implications and the further study topics.
A Study on Reliability Centered Maintenance of AGT Vehicle System
Journal of the Korean society for railway, volume 7, issue 3, 2004, Pages 271~277
This paper is concerned with the reliability centered maintenance (RCM) of the Automated Guideway Transit (AGT) vehicle system. Korea Railroad Research Institute (KRRI) has developed the AGT vehicle system from 1999 to 2004. The provisions for a specific maintenance system including RAMS (reliability, availability, maintainability & safety) of AGT vehicle system is necessary for maintaining good operation conditions. RCM is a process used to determine what must be done to ensure that any system continues to do whatever its users want it to do in its present operating conditions. Therefore, we introduce RCM in details and describe how RCM should be applied to AGT vehicle system on Gyeong-San test line. Analyses to approach RCM to AGT vehicle system are demonstrated in the seven steps that contain each main task and detailed operating conditions.
A Study on Establishment of the Standard Exhibition Space in the Railroad Cars
Journal of the Korean society for railway, volume 7, issue 3, 2004, Pages 278~282
A Railroad Cars playa prominent role in a matter of transportation however, yet it cannot be discussed here for cultural space. On the other hand, considering railroad customers' increaced desire(craving) for cultural space, we design it in the train so that we provide customers not only transportation but also fullfil them desire for culture. In the competitive cultural era. The aim of the new strategy for railroad business is both inspiving art and operating exhibition facilities in the train(railroad). Through analysis of exhibition space and environment, we design exhibition space to equip cultural facilities in the train then lead to make railroad business' new social education role by the inside and outside of the country.
The Effect and Countermeasures of The Vertical Track Settlement Caused by Expand and Contract Behavior of the High-Speed Railway Bridge Girder
Journal of the Korean society for railway, volume 7, issue 3, 2004, Pages 283~289
According to continuos welded rails on a bridge, temperature changes bring about the expansion of the bridge deck adding axil forces on the track. Moreover, the ballast on the bridge deck expansion joint is moved due to the bridge deck. If bridge decks are longer, the influence is greater, loosening ballast, causing track irregularities, and deteriorating passengers' comfort. Considering structure of bridge itself and tolerance of track irregularities caused by the loosened ballast on bridges, the maximum length of a deck should be less than 80m, which is the same as the standard of the French railway. In this study, an interaction between the expansion related to the bridge length and irregularity in longitudinal level referring to measurements and maintenance works performed in the high-speed railways was analyzed. This research shows that installation of sliding plate or vertical ballast stopper is not a good option since it is difficult to install. On the other hand, installation of movable fastener or gluing is easy but its influence is insignificant. To conclude, switch tie tamping or manual tamping is more effective than others.