• Title, Summary, Keyword: Track irregularity

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A Study on the Reliability of Various Track Recording Data (다양한 궤도틀림 데이터의 신뢰성 검토)

  • Lee, Jee-Ha;Ahn, Sung-Hyuk;Park, Hye-Jong;Kim, Bag-Jin
    • Proceedings of the KSR Conference
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    • pp.435-441
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    • 2011
  • Track geometry changes by traffic loads. The bigger the changes are, the worse the riding comfort and running stability of train. This is so-called track irregularity and is the most important quality parameters of ballasted track. To objectively assess track irregularity, track geometry should be able to be measured. Practically, railway companies in Korea use various track recording equipments to measure track irregularity. But this various equipments output different data due to their geometrical structure even measured at same location. In this report, the correlation of various track recording data used in Korea was reviewed.

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Sensitivity of the ballast resistance and track irregularity on the track stability (궤도 안정성에 대한 도상저항력과 궤도틀림의 민감도)

  • Lim, Nam Hyoung;Choi, Sang Hyun;Lee, Chin Ok;Sung, Ik Hyun
    • Journal of Korean Society of Steel Construction
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    • v.17 no.5
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    • pp.519-526
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    • 2005
  • During summer, very high compressive force occurs on the continuous welded rail (CWR) track because of the increase of rail temperature (max. $60^{\circ}C$). This extreme temperature stress can cause the CWR track to buckle. Among many CWR parameters affecting the track buckling, the influence of the lateral and longitudinal ballast resistance was investigated on the stability of the CWR track in this study. Also, the sensitivity of the track irregularity such as the alignment defect and the gauge irregularity was investigated.

Probability Distribution of Track Recording Data (궤도틀림 검측 데이타의 확률분포 검토)

  • Lee, Jee-Ha;Na, Sung-Hoon;Kim, Bag-Jin;Lee, You-Bok
    • Proceedings of the KSR Conference
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    • pp.310-314
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    • 2010
  • Track geometry changes by traffic loads. The bigger the changes are, the worse the riding comfort and running stability of train. This is so-called track irregularity and is the most important quality parameters of ballasted track. To objectively assess track irregularity, track geometry should be able to be measured. Practically, railway companies in Korea use normal distribution as probability distribution of track irregularity. But some countries use non-normal distribution according to their own track recording system. In this report, reviewed probability distribution of Kyung-Bu high-speed line and tested normality.

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Characteristics of Track and Train Behaviors on High-Speed Railway Bridge/Earthwork Transiton Zone (고속철도 교량/토공 접속부에서의 궤도 및 차량 거동 특성)

  • Lee, Il-Wha;Kang, Yun-Suk;Kim, Eun;Son, Ki-Jun;Park, Chan-Kyoung
    • Proceedings of the KSR Conference
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    • pp.129-134
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    • 2003
  • It is very important to pay careful attention to construction of bridge/earthwork transition zone for high-speed railway. The transition zone of the railway is the section which roadbed stiffness is suddenly varied. Differences in stiffness have dynamic effects and these increase the forces in the track and the extent of deformation. An abrupt change of stiffness across two adjacent track portions cause irregular settlement of roadbed, track irregularity, lack of girder bending moment and reduction of lateral resistance. Especially on high-speed railway, track irregularity of transition zone cause sincere effect to track stability and train safety. And so continuous maintenance is needed. To verify this effect and to improve transiton zone capacity, In situ test, track irregularity and train acceleration test were performed on high-speed railway bridge/earthwork Transiton Zone.

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Analysis method for the Measured Track Geometry Data using Wavelet Transform (웨이브렛 변환을 이용한 궤도틀림 분석)

  • Lee, In-Kyu;Kim, Sung-Il;Yeo, In-Ho
    • Journal of the Korean Society for Railway
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    • v.9 no.2
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    • pp.187-192
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    • 2006
  • The regularity of railway track alignment is a crucial component fur maintaining travel safety and the smoothness of passenger ride. The conventional spectral analysis has been considered to estimate the severity of the track irregularity from measured data. The time domain data used to be changed into the frequency domain by Fourier transform. Because the measuring points can be regarded as the time points, the spatial-frequency can be introduced instead of the time-frequency. Although FFT(Fast Fourier Transform) and/or PSD(Power Spectral Density) function could provide fairly localized information within frequency domain, but chronical configurations of data could be missed. In this study, we attempt to apply the Morlet wavelet transform for the purpose of a frequency-time-domain analysis rather than a frequency-domain analysis. The applicability of wavelet transform is examined for the estimation of the track irregularity with real measured track data on the section of Kyoung-bu line by EM-120 measuring vehicle. It is shown that the wavelet transform can be an effective tool to manage the track irregularity.

Track Irregularity Inspection Method for Commercial Vehicle (영업차량에서의 궤도비틀림 검측 방안 연구)

  • Lee Chan-Woo;Choi Eun-Young
    • Proceedings of the KSR Conference
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    • pp.768-773
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    • 2003
  • The inspection of track irregularity, which is the most important index for the evaluation of the dynamic safety of the rolling stock, is performed by setting up the testing train set. The self-diagnosis for the various rolling stocks and railways can be obtained if it is possible to take the simultaneous inspection of track irregularity for the commercial vehicle while it is running and to build up a dynamic safety evaluation system. It is expected to have some good effects, such as preventing accident with the low dynamic safety, cutting cost for the testing train set and evaluating the exact influence on the rolling stock and railway. In this study, innertial measuring method, which allows us to directly measure the track irregularity from the commercial vehicle, will be considered and some overseas cases will be explored as well.

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Dynamic Analysis of Structure's Approaches through Field Tests in the Conventional Railway (현장계측을 통한 기존선 철도 구조물 접속부의 거동분석)

  • Park, Joon-Oh;Lee, Sang-Bae;Hong, Won-Pyo
    • Proceedings of the KSR Conference
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    • pp.1864-1874
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    • 2007
  • Korean trains pass many mountain areas, so the volume of structures like bridge and tunnel has large part of railway lines. Train speed-up naturally needs a straight line in railway, then structures are increasing, and the length of structure has more than 70% in Kyongbu high-speed railway. The stiffness of bridge and tunnel is higher than the soil in the roadbed in spite of dynamic difference in vibration and displacement. Differences in stiffness have more dynamic effects and increase the deformation and destruction in the track and roadbed. This influences passenger's comfort and the safety of operation, and it needs more track maintenance. This study selected tunnel with ballast track, tunnel with concrete track, and structure's approaches with short maintenance cycle in the roadbed and had track acceleration tests and track liner inspections using track master in the field. This study will measure periodically to structure's approaches which have very fast track irregularity and analyze dynamic differences and track irregularity near structure's approaches, so realize the cause of track irregularity of structure's approaches and use basic data for reasonably strengthening method of structure's approaches.

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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
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    • pp.369-375
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    • 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.

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A Study of Reinforcement of Railway Structure Approaches in Conventional line (기존선 철도구조물 접속부의 보강에 대한 고찰)

  • Park, Joon-Oh;Lee, Sang-Bae;Kim, Kwan-Hyung
    • Proceedings of the KSR Conference
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    • pp.442-452
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    • 2007
  • Korean trains pass many mountain areas, so the volume of structures like bridge and tunnel has large part of railway lines. Train speed-up naturally needs a straight line in railway, then structures are increasing, and this influences passenger's comfort and the safety of operation, and it needs more track maintenance. The stiffness of bridge and tunnel is higher than the soil in the roadbed in spite of dynamic difference in vibration and displacement. Differences in stiffness have more dynamic effects and increase the deformation and destruction in the track and roadbed. This study will measure periodically to structure's approaches which have very fast track irregularity and analyze dynamic differences and track irregularity near structure's approaches, so realize the cause of track irregularity of structure's approaches and use basic data for reasonably strengthening method of structure's approaches.

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Evaluation of Track Irregularity Effect due to Adjacent Excavation on Serviced Railway Line (철도시설물 인접굴착공사에 따른 운행선 궤도의 궤도틀림 영향 평가)

  • Choi, Jung-Youl;Park, Dong-Ryong;Chung, Jee-Seung
    • The Journal of the Convergence on Culture Technology
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    • v.5 no.4
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    • pp.401-406
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    • 2019
  • The three-dimensional precision numerical analysis was performed using the finite element model applied with the railway track model consisting of rails, sleepers, and track elastic springs(ballast, rail pad). As a result of analyzing the track deformation level of the existing tracks due to the excavation work adjacent to the railway facilities, it was found that the track irregularity evaluation criteria (allowed values) of both conventional and high-speed railways lines were satisfied. Based on the numerical analysis using the track model, it was analyzed that the results of the prediction of the track irregularity due to the excavation work and the level of the track deformation occurring at the actual site could be approximated as closely as possible.