• Transactions of the Korean Society for Noise and Vibration Engineering
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• v.22 no.11
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• pp.1078-1088
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• 2012

Recently, the vibration and structure-borne noise induced by passing trains are of great concerns, and the floating slab track is highlighted as one of most efficient alternatives to reduce the railway vibration. However, due to the non-linearity and viscosity of rubber spring used in the floating slab track, its dynamic behavior is very complex. In this study, therefore, to simulate the dynamic behavior of floating slab track with a better accuracy, a nonlinear viscoelastic rubber spring model that can be incorporated in commercial finite element analysis codes has been proposed. This model is composed of a combination of elastic spring element, friction element and viscous element, and termed the "generalized friction viscoelastic model(GFVM)". Also, in this study, the method to determine the model parameters of GFVM based on Berg's 5-parameter model was presented. The results of the finite element analysis with this rubber spring model exhibit very good correlation with the test results of a laboratory mock-up test, and the feasibility of GFVM has been verified.

• Proceedings of the KIEE Conference
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• 2007.04c
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• pp.234-236
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• 2007

Even though the existing train route controlling method, using track circuits, ensures the sufficient number of operation, it still has problems such as discordance between train numbers which was planned for operating and train numbers being operated on the track, and allowing only one train entering for one route. To solve those problems, we study and develop the Smart train route controlling system which uses the real-time informations of train positions. This system enables improve the coefficient of utilization in a certain train route controlling section, and the safety level of train route controlling, but we should ensure satisfying reliability of data about tracks operated by trains. In addition, there is a need to protect accidents caused by erroneous information of train position, by reflecting changes of tracks, for example maintenance, improvement, expansion of tracks. In this paper, we describes data structure of a developed program which required to change CAD files to wiring diagrams and to generate them to data of tracks. And we show the result that the simulator, using the data structure, controls speed and route of trains without problems.

• Journal of the Korean Society of Hazard Mitigation
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• v.8 no.1
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• pp.23-29
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• 2008

The railway system is worldwide recognized as a safe mean of transportation. However, railroad accidents and incidents continue to occur. Due to the nature of the railway system that consist of many mechanical parties, it is apparently difficult to eliminate probability of accidents and incidents completely. Therefore, through the analysis of railroad accidents and incidents, it is very important to trace the various factors affecting the accidents and incidents. In this study, we performed the analysis of rail-road accidents due to track defects in foreign countries; United States of America, England, Canada, Australia. As a result of its investigation of the accidents, major risk factors are proposed in this study.

• Journal of the Korean Society for Railway
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• v.12 no.5
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• pp.800-805
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• 2009

This paper proposes the track system with twin block sleeper for a LIM type maglev railroad. Because a LIM type maglev railroad is expected to be constructed in inner city, social costs can be required under construction. Accordingly, superstructure using precast plate was adopted and twin block sleeper which can be constructed together with precast plate was developed to reduce the construction period. To examine the structural safety of the proposed track system with twin block sleeper, the finite element analyses and the laboratory experiments were performed. Also, the workability of the proposed track system was investigated through the construction simulation test and construction experience in test bed.

• Journal of the Korean Society for Railway
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• v.15 no.6
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• pp.604-608
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• 2012

Traditionally, the track circuits have been used for the purpose of train locating. However, the recent train control systems like a CBTC(Communications Based Train Control) do not utilize the track circuits to minimize the amount of ground signal devices. Therefore, there are increasing concerns over the system that can locate the position of train exactly without using the track circuits. Then, the contactless locating methods are added to ensure safety when the shunting sensitivity of the track circuit becomes low for the existing sections equipped with the track circuits. In this paper, a prototype of train locating device has been designed and tested, which utilizes the current phase difference upon magnetic field variation. The results show improved features of this method over the conventional track circuits method.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.31 no.6D
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• pp.867-874
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• 2011

The ballast abrasion occurs on the ballasted track upon bridges more than soil roadbed because the track vibration occurs a lot in the ballasted track upon bridges due to girder vibration when a train's weight is loaded onto track even though the identical ballast is used. The phenomena of mud pumping especially, which occurs when drainage is not properly secured for heavy rain, leads to the increase of maintenance work load and the decline of ride comfort. The ballast thickness range in domestic railroad construction rule is uniformly set up according to the design speed of railroad and passing tonnage of train without considering field conditions which is considered in foreign railroad companies. The purpose of this study is to verify the effect of vibration decrease by measuring the acceleration, displacement and ride comfort of ballasted track with the change of ballast thickness on the ballast tracked bridges and to suggest the optimal height of ballast on the Yocheon Bridge built for the test in Honam Line.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.10 no.12
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• pp.3594-3599
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• 2009

The train control system used in Gyeongbu-line is classified in ATC, IXL and CTC. The ATC data related to speed and space control for trains are transmitted from wayside to onboard by way of UM71 AF track circuits and BSP Loop. The information transferred by track circuits is composed of operation data which directly influence to the train operation and the information transferred by BSP Loop is used in the section which requires the additional data transmission about the particular track-side environment such as tunnel, hot box detector or insulated section. In this paper, for the BA type turning unit of the UM71 AF track circuits which is mainly used in the linking section of existing and high-speed lines from the opening of the Gyeongbu line till the present, we not only analyze the characteristics of BA but also compare and analyze baseline values and the measured values. With this analysis, we will be able to propose how to solve the problems about operation and maintenance such as track circuit malfunctions of the relevant sections.

• Proceedings of the Korean Geotechical Society Conference
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• 1999.03a
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• pp.391-398
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• 1999

Dynamic properties of hydraulic mechanically stabilized slag(HMS25) was studied for utilizing it as a roadbed material. HMS25 is a by product material during pig iron production process. It has a very good potential application as a roadbed material. Therefore, the resonant column and torsional shear tests were carried out to evaluate the dynamic properties of HMS25 which are necessary for designing roadbed of railroad track. As a result, it was found that HMS25 has excellent dynamic properties required for roadbed material used in railroad track.

• Proceedings of the KIEE Conference
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• 2001.07b
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• pp.1236-1238
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• 2001

The electrified railway has various power supply schemes. Although the identical trains are operated in same condition and the impedance of track are equal, the genealogy impedance of track is changed according to composition method of feeding scheme. So, the collection voltage of train and supplying power from railway substation are greatly unlike. For simulation of collection voltage and power supply according to feeding scheme, using 6-port network analysis proposed previously simulate collection voltage and supply power according to feeding scheme(Parallel Post feeding system, normal feeding system and tie feeding system) and compare and investigate each characteristics.

• Proceedings of the Korean Geotechical Society Conference
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• 2009.09a
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• pp.350-358
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• 2009

To enhance the application of the reinforced retaining walls in the railway industry, this paper suggested a type of reinforcement subgrade with short reinforcement and rigid facing. To become popular the reinforced retaining walls in the industry, the deformation of retaining walls should be controlled below some limited level. In this paper, small scale and full scale tests of the proposed retaining walls were performed and their deformation characteristics were evaluated. Even though it has short reinforcement, the rigid type retaining wall had small deformation to the external train loading than the segmental type retaining wall had.