• Title, Summary, Keyword: CWR(Continuous Welded Rail) track

Search Result 59, Processing Time 0.038 seconds

An Experimental Study of Fastening System on CWR(Continuous Welded Rail) Track Stability (장대레일 궤도의 안정성에 미치는 체결장치의 실험적 연구)

  • Kim, Jung-Hun;Han, Sang-Yun;Lim, Nam-Hyoung;Kang, Young-Jong
    • Proceedings of the KSR Conference
    • /
    • /
    • pp.317-324
    • /
    • 2007
  • Until now, the railway has been constructed using track with jointed rails of relatively short lengths to allow thermal expansion in hot summer months. These joints weaken the track structurally and increase track maintenance cost and power consumption of the running train. The CWR(Continuous Welded Rail) Track is the solution of these drawbacks. Although the CWR track not only reduces the track maintenance cost but also increases the life cycle of track components, the stability of the track is highly affected by change of temperatures and vehicle load. A three dimensional nonlinear analysis which considers rail, fastening system and tie has been performed to understand structural behavior of the CWR track. In this case, the translational and rotational stiffness values of fastening system have not been studied. The fastening system makes ties and rails connect. In this study, the stiffness values of various types of fastening systems which consist of clips, rail-pads and insulators are determined by the experiment. The experimental results of the fastening system are compared with the results of parametric study that is performed to investigate the sensitivity of fastening system on stability of CWR track.

  • PDF

Parametric Study on the Safety of CWR Track over High-Speed Railway Bridges (매개변수해석을 통한 고속전철교량상 장대레일궤도 안전성 검토)

  • 강재윤;김병석;김영진;박성용;조정래;최은석;진원종
    • Journal of the Korean Society for Railway
    • /
    • v.5 no.1
    • /
    • pp.1-9
    • /
    • 2002
  • Where the track is continuously welded over the bridge, the longitudinal forces will be distributed interactively between the track and the sub-structure by the rail-bridge interaction mechanism. The ratio between the longitudinal forces transmitted in each elements depends on the magnitude of the ballast resistance and the stiffness of the sub-structures. In this paper, the main factors affect on the longitudinal rail force are discussed and the parametric study for the behavior of CWR(Continuous Welded Rail) track was executed. It is concluded that the horizontal ballast resistance and the stiffness of the bridge sub-structure are the significant parameters affecting the stability of the continuous welded rail track.

Field Test to Investigate the Thermal Stress of Continuous Welded Rail on High Speed Railway Bridges in Summer Period (고속철도 교량상 장대레일의 하절기 온도응력 계측)

  • Kwark, Jong-Won;Choi, Eun-Suk;Chin, Won-Jong;Lee, Jung-Woo;Kim, Byung-Suk;Kang, Jae-Yoon
    • Journal of the Korean Society for Railway
    • /
    • v.9 no.2
    • /
    • pp.131-136
    • /
    • 2006
  • Most modern railways, especially the high speed railway tracks, use continuous welded rail(CWR) for the less maintenance. For the CWR track has very few expansion joints, track buckling has always been an unpredictable event and it happens mainly by high compressive stress in rail in summer period. Therefore, it is important to understand the variation of rail stress induced by thermal loads which has direct influence on the rail buckling and stability of railway track. This paper describes the experimental investigation of the variation of rail temperature and stress in a high speed railway track on bridge structure. Field measurement was performed to examine the correlation between the rail temperature and rail stress on the Korean High Speed Railway line. Regression functions were derived from measured data to determine the rail stress f3r an arbitrary rail temperature varies from 20 to 50 degree Celsius.

Investigation of Thermal Stress of Continuous Welded Rail on High Speed Railway Bridge (경부고속철도 교량상 장대레일의 온도응력 계측 실험)

  • Kang, Jae-Yoon;Choi, Eun-Suk;Chin, Won-Jong;Lee, Jung-Woo;Kwark, Jong-Won;Kim, Byung-Suk
    • Proceedings of the KSR Conference
    • /
    • /
    • pp.458-461
    • /
    • 2007
  • Recently, the continuous welded rail(CWR) track has been used for less maintenance of the High-speed railway tracks. In case of CWR track, track buckling has always been an unpredictable event under the high compressive stress in rail. The behavior and stress state of CWR track is manily influenced by its thermal variations, and it is important to understand seasonal variations of rail temperature and stress to predict the track stability. This paper describes the in-site measurement for the rail temperature and rail stress, and the correlation between the rail temperature and stress was examined.

  • PDF

The Growth friend Analysis of Rail Surface Irregularity according to the Types of Track (궤도구조별 레일두부 표면요철의 성장 경향 분석)

  • Sung, Deok-Yong;Kong, Sun-Yong;Kim, Bag-Jin;Shin, Hyo-Jeong;Park, Yong-Gul
    • Proceedings of the KSR Conference
    • /
    • /
    • pp.369-375
    • /
    • 2009
  • The Periodic replacements criterion of rail is calculated on the basis of the research result of RTRI in Japan. It is suggested that the service life of the continuous welded rail(CWR) is estimated by the relationship between the rail surface irregularity according to the accumulated passing tonnage and bending fatigue of welded part in CWR. In order to establish the periodic replacements criterion of CWR, this study measured the rail surface irregularity according to the accumulated passing tonnage, the types of track system and welding. Therefore, it is analyzed that the gas pressure welding is the worst one of the others. In addition, it is analyzed that the rail surface irregularity growth rate in ballast track is about $0.02{\sim}0.03mm$/100MGT and its in concrete track is about $0.005{\sim}0.02mm$/100MGT Finally, the result of this study is able to use the basis data to establishing the periodic replacements criterion of CWR considering rail grinding.

  • PDF

Three Dimensional Buckling Analysis of Continuous Welded Rail Track Under Thermal Load (온도하중을 고려한 장대레일 궤도의 3차원 좌굴 거동)

  • 강준석;임남형;양신추;강영종
    • Proceedings of the KSR Conference
    • /
    • /
    • pp.471-478
    • /
    • 2000
  • For many decades, the railway was constructed using tracks with jointed rails of relatively short lengths. The joints cause many drawbacks in the track and lead to signeficant maintenance cost. so, railroad engineers became interested in eliminating joints. 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, firstly, 3-D CWR track model and CWRB program exactly considering the influence of tie are developed far linear static and buckling analysis using finite element method. Characteristics of CWR track model are using 7-dofs beam element as rail, Offset technic exactly considering centroid axies difference of track components(rail, rail-pad-fastener, tie), and Thermal gradient considering thermal difference of top flange and bottom flange in rail section.. second,, Through the static and linear buckling analysis by CWRB, Influences of various track components (rail, ballast, fastener, tie and so on..) on CWR track behavior and stability was characterized.

  • PDF

Parametric Study of Thermal Stability on Continuous Welded Rail

  • Choi, Dong-Ho;Na, Ho-Sung
    • International Journal of Railway
    • /
    • v.3 no.4
    • /
    • pp.126-133
    • /
    • 2010
  • The thermal buckling analysis of curved continuous welded rail (CWR) is studied for the lateral buckling prevention. This study includes a thermal buckling theory which accounts for both thermal and vehicle loading effects in the evaluation of track stability. The parameters include rail size, track lateral resistance, track longitudinal and torsional stiffnesses, initial misalignment amplitude and wavelength, track curvature, tie-ballast friction coefficient and truck center spacing. Parametric studies are performed to evaluate the effects of the individual parameters on the upper and lower critical buckling temperatures. The results show that the upper critical buckling temperature is highly affected by the uplift due to vehicle loads. This study provides a guideline for the improvement of stability for dynamic buckling in curved CWR track.

  • PDF

Sensitivity of the Continuous Welded Rail and the Fastener on the Track Stability (궤도 안정성에 대한 장대레일과 체결구의 민감도)

  • Han, Sang Yun;Park, Nam Hoi;Lim, Nam Hyoung;Kang, Young Jong
    • Journal of The Korean Society of Civil Engineers
    • /
    • v.26 no.4A
    • /
    • pp.719-726
    • /
    • 2006
  • The use of CWR track not only reduces the track maintenance cost, but increase the life cycle of track components. Therefore, the use of the CWR track has increased consistently in the worldwide. As the use of CWR increases in track structures, derailing disasters associating with track buckling also increase in great numbers due to high compressive thermal stress in the summer. Among many CWR parameters, the influence of the sectional properties of the rail was investigated on the stability of CWR track in this study. Also, the sensitivity of the broken fastener and the stiffness of the fastener system such as the translational and rotational stiffness was investigated.

  • PDF

Thermal Buckling Analysis of Continuous Welded Rail Track (장대 레일의 온도 좌굴 해석)

  • 신정렬;임남형;양재성;강영종
    • Proceedings of the Computational Structural Engineering Institute Conference
    • /
    • /
    • pp.433-440
    • /
    • 1998
  • For many decades, railroad technology was used to set up tracks with jointed rails and lengths in accordance with rolling and handling technology. The joints lead to drawbacks in the track and in controlling rising maintenance costs. So, railroad engineers became interested in eliminating joints to increase loads, speeds and improvements in rolling, welding, and fastening technology. Continuous welded rail(CWR) track has many advantages over the conventional jointed-rail track. In the case of the elimination of rail joints, it may cause the track to be suddenly and laterally buckled by thermal forces and vehicle load. Thermal forces are caused by an increase in the temperature of railway track. For many years, many analytical and experimental investigations have been conducted to improve the safety of CWR track by various research center in many country. In this paper, CWR track model and CWRB program is developed for buckling analysis using finite element method(FEM). The finite element discretization is used for a rail element with a total of 14 degrees of freedom. The stiffness of the fasteners, tie, and ballast bed is included by a set of spring elements. The investigation on the buckling modes and temperature of CWR track is presented in this paper

  • PDF

Estimation of Bending Fatigue Life of CWR in Concrete Track (콘크리트궤도 장대레일의 휨 피로수명 평가)

  • Sung, Deok-Yong;Tae, Sung-Sik;Park, Kwang-Hwa;Kong, Sun-Yong;Park, Yong-Gul
    • Proceedings of the KSR Conference
    • /
    • /
    • pp.64-71
    • /
    • 2010
  • It is suggested that the service life of the continuous welded rail(CWR) is estimated by the relationship between the rail surface irregularity according to the accumulated passing tonnage and bending fatigue of welded part in CWR. In this study, based on the results of bending fatigue tests of rail and results of measuring tests in situ of rail bending stress, this study estimated the bending fatigue life of welded rail in concrete track, adopting a Haibach's rule. The bending fatigue life of CWR considered the rail surface irregularity, train speed and the S-N curve by types of rail welding. In addition, this study estimated it for the fracture probability 1%, 0.1%, 0.01%. Therefore, this study proposed bending fatigue life of CWR in concrete track.

  • PDF