• Title, Summary, Keyword: Rail Stability

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A Study on the Influence of Track Stability for Ballast Resistance Force (도상저항력이 궤도 안전성에 미치는 영향)

  • 박준명;이방우;박선규;이종득
    • Journal of the Korean Society for Railway
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    • v.6 no.3
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    • pp.169-173
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    • 2003
  • Transportation by railroad is superior to other transport in a mass transport, stability, rapid transit, delightfulness and low-pollution etc. But, it need to ensure a track stability that supports the train-load for high-speed in transportation by railroad. Ballast resistance force resists against the buckling of track taking a rail-tie's place. So, it plays an important role in a careful train-service. So, in this papers, we forced on measuring and theorizing about the Ballast Resistance Force that play a key role in track stability and high-speed. And we studied the mechanical property. Finally, we suggested the method of securing Ballast Resistance Force and the report for a careful train-service in high-speed.

Stability Analysis for CWR on the Railway Bridges by Linearized Method (선형해석법을 이용한 교량상 장대레일의 안정성 해석 방법 연구)

  • Choi, Young-Gil;Oh, Ju-Won
    • Journal of the Korean Society for Railway
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    • v.12 no.4
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    • pp.472-480
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    • 2009
  • The stability analysis for CWR is difficult in the theory itself because both geometric and material nonlinearity should be considered. Also the analysis results are varied according to the loading history. In contrast to the complexity in the theory, the analysis results for CWR on the railway bridges are quite simple and can be predicted because of a small buckling effect and its negligible nonlinearity. In this study, refined nonlinear analysis methods for the stability analysis of CWR on the railway bridges were developed which consider only material nonlinearity beeause the effects of geometric nonlinearity are nominal. In this study, the analysis results can be found within limited number of iterations with idealized linear force-displacement relationship. From the analysis result comparisons, it was found that the stability analysis for CWR on the railway bridges can be performed effectively by this method.

The Reinforcement Effect of Woven Geotextiles for Railway Roadbed High-Embankment on Soft Ground by the Limit Equilibrium Analysis (한계평형해석에 의한 연약지반 위의 철도노반 고성토를 위한 직포 보강 효과)

  • Kim, You-Seong;Choi, Jae-Seon
    • Journal of the Korean Geosynthetics Society
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    • v.9 no.4
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    • pp.27-37
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    • 2010
  • Woven geotextiles (polyester mats) reinforcement is generally used to improve traffic ability, bearing capacity, and slope stability for embankment construction on soft ground. Cases of two high-strength woven geotextiles reinforcement layers are introduced in the present paper, which has been successfully constructed for rail road embankment on soft ground. According to the case results based on the limit equilibrium analyses of slope stability, the two high-strength woven geotextiles reinforcement layers on the soft ground can substantially increase the stability of the embankment by about 25%, improve the safety factor from 0.91 to 1.14, and significantly reduce the embankment construction duration at least 2 months. Therefore, the application of high-strength woven geotextiles is found to be useful for in-situ cases having the lack of construction duration and stability, as a soft ground improvement.

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Monitoring in-service performance of fibre-reinforced foamed urethane sleepers/bearers in railway urban turnout systems

  • Kaewunruen, Sakdirat
    • Structural Monitoring and Maintenance
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    • v.1 no.1
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    • pp.131-157
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    • 2014
  • Special track systems used to divert a train to other directions or other tracks are generally called 'railway turnout'. A traditional turnout system consists of steel rails, switches, crossings, steel plates, fasteners, screw spikes, timber bearers, ballast and formation. The wheel rail contact over the crossing transfer zone has a dip-like shape and can often cause detrimental impact loads on the railway track and its components. The large impact also emits disturbing noises (either impact or ground-borne noise) to railway neighbors. In a brown-field railway track where an existing aged infrastructure requires renewal or maintenance, some physical constraints and construction complexities may dominate the choice of track forms or certain components. With the difficulty to seek for high-quality timbers with dimensional stability, a methodology to replace aged timber bearers in harsh dynamic environments is to adopt an alternative material that could mimic responses and characteristics of timber in both static and dynamic loading conditions. A critical review has suggested an application of an alternative material called fibre-reinforced foamed urethane (FFU). The full-scale capacity design makes use of its comparable engineering characteristics to timber, high-impact attenuation, high damping property, and a longer service life. A field trial to investigate in-situ behaviours of a turnout grillage system using an alternative material, 'fibre-reinforced foamed urethane (FFU)' bearers, has been carried out at a complex turnout junction under heavy mixed traffics at Hornsby, New South Wales, Australia. The turnout junction was renewed using the FFU bearers altogether with new special track components. Influences of the FFU bearers on track geometry (recorded by track inspection vehicle 'AK Car'), track settlement (based on survey data), track dynamics, and acoustic characteristics have been measured. Operational train pass-by measurements have been analysed to evaluate the effectiveness of the replacement methodology. Comparative studies show that the use of FFU bearers generates higher rail and sleeper accelerations but the damping capacity of the FFU help suppress vibration transferring onto other track components. The survey data analysis suggests a small vertical settlement and negligible lateral movement of the turnout system. The static and dynamic behaviours of FFU bearers appear to equate that of natural timber but its service life is superior.

A Study on the Design of Small-Scaled Derailment Simulator considering Similarity Rules (상사법칙을 고려한 소형탈선시뮬레이터 설계에 관한 연구)

  • Eom, Beom-Gyu;Lee, Se-Yong;Oh, Se-Been;Kang, Bu-Byoung;Lee, Hi-Sung
    • Proceedings of the KSR Conference
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    • pp.1085-1091
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    • 2011
  • The dynamic stability of railway vehicle has been one of the important issues in railway safety. The dynamic simulator has been used in the study about the dynamic stability of railway vehicle and wheel/rail interface. Especially, a small scale simulator has been widely used in the fundamental study in the laboratory instead of full scale roller rig which is not cost effective and inconvenient to achieve diverse design parameters. But the technique for the design of the small scale simulator for the fundamental study about the dynamic characteristics of the wheel-rail system and the bogie system has not been well developed in Korea. Therefore, the research about the development of the small scale simulator and the bogie has been conducted. This paper presents the design of the small-scaled derailment simulator and the example design case of a small scale bogie. The simulator could be used in the study about the effect of diverse parameters such as attack angle, wheelbase and cant on dynamic behavior of the bogie and the safety parameter such as derailment coefficient and critical speed.

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Design of Small-Scaled Derailment Simulator for Investigating Bogie Dynamics

  • Eom, Beom-Gyu;Kang, Bu-Byoung;Lee, Hi-Sung
    • International Journal of Railway
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    • v.4 no.2
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    • pp.50-55
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    • 2011
  • The dynamic stability of railway vehicle has long been one of the important issues in railway safety. The dynamic simulator has been used as a tool for investigating the dynamic stability of railway vehicles and wheel/rail interfaces. In particular, small scale simulators have been widely used in laboratory studies instead of full scale roller rigs which can be quite costly and rather inconvenient for testing out the effect of diverse design parameters. But techniques for design of a small scale simulator for the fundamental study about the dynamic characteristics of the wheel-rail systems and the bogie systems have not been well developed in Korea. Therefore, a research on the development of a small scale simulator for investigating bogie dynamics needs to be undertaken. The present paper investigates design of a small-scaled derailment simulator and the design of a small scale bogie. The simulator developed can be used to investigate the effect of diverse parameters such as attack angle, wheelbase and cant on dynamic behavior of the bogie and key dynamic performance parameters such as derailment coefficient and critical speed.

Structural Optimization for a Jaw Using the Kriging model (이단계 크리깅 모델을 이용한 조(Jaw)의 구조최적설계)

  • Lee, Kwon-Hee;Bang, Il-Kwon;Kang, Dong-Hun;Han, Dong-Seop;Han, Geun-Jo
    • Proceedings of the Korean Institute of Navigation and Port Research Conference
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    • v.2
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    • pp.143-147
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    • 2006
  • The rail clamp is the device to prevent that a crane slips along rails due to the wind blast as well as locate the crane in the set position for loading and unloading containers. The wedge type rail clamp should be designed to consider the structural stability and the durability because it compresses both rail side with large clamping force by the wedge working as the wind speed increases. In this research, the kriging interpolation method using sequential sampling is utilized to find the optimum shape of the jaw in the rail clamp. The suggested method predicts more accurate response value than the response surface method. The optimum results obtained by the proposal method are compared with those by the commercial software.

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Stability of Continuous Welded Rail Track under Thermal Load (온도하중을 고려한 장대레일 궤도의 안정성 해석)

  • Kang, Young Jong;Lim, Nam Hyoung;Shin, Jeong Ryol;Yang, Jae Seong
    • Journal of Korean Society of Steel Construction
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    • v.11 no.3
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    • pp.281-290
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    • 1999
  • For many decades, the railway was constructed using tracks with jointed rails of relatively short lengths in accordance with rolling and handling technology. The joints cause many drawbacks in the track and lead to significant maintenance cost. So, railroad engineers became interested in eliminating joints to increase service loads ana speeds by improving rolling, welding, and fastening technology. Continuous welded rail(CWR) track has many advantages over the conventional jointed-rail track. But, in the case of the elimination of rail joints, it may cause the track to be suddenly buckled laterally by thermal loads. In this paper, CWR track model and CWRB program are developed for linear buckling analysis using finite element method. Rail element with a total of 14 degrees of freedom is used. The stiffness of the fastener, tie, and ballast bed are included by a set of spring elements. The investigation on the buckling modes and temperature of CWR track is presented.

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