• Title/Summary/Keyword: Track measurement

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Development of Rail Profile Measurement System using High Speed Laser Image Processing (고속영상처리에 의한 레일형상측정시스템 개발)

  • Moon, Chul-Yi;Kim, Man-Chul
    • Proceedings of the KSR Conference
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    • 2006.11b
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    • pp.1320-1325
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    • 2006
  • Railway track supports and guides train and it directly affects ride quality and safety. To maintain track quality, regular maintenance activity is essential but it degrades track usage since maintenance activity occupies the track during the work. To achieve maximum track efficiency, track inspection should be performed at commercial running speed. In this paper, we designed and developed high speed rail profile measurement system using laser light sectioning method with line laser generator, digital camera and DSP based image processing system. The measurement system can supports rail profile measurement at the speed of 300 Km/h that can be applied to KTX.

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Influence of Vehicle Vibration on Track Geometry Measurement (차량 진동이 궤도 선형 측정에 미치는 영향)

  • Bae, Kyu-Young;Yong, Jae Chul;Kim, Lee-Hyeon;Kwon, Sam-Young
    • Transactions of the Korean Society for Noise and Vibration Engineering
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    • v.26 no.6_spc
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    • pp.644-650
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    • 2016
  • Track maintenance works based on track geometry recordings are essential to enhance the safety and comfort of railway transportation. Usually, the track irregularity has been measured by a special inspection trains which all were imported from abroad. Because the inspection train speed is limited under 160 km/h, it takes a long time to inspect railways and there is difficulty in daytime operation. To solve this problem, we started to develop a track geometry measuring system (TGMS) with measurement speed up to 300 km/h which can be installed in commercial vehicles such as HEMU-430X. In this paper, we introduce a newly developed inertial TGMS and propose two inertial navigation system (INS) algorithms (method A, B) for measuring track geometry. In order to investigate advantage and disadvantage of each algorithm, we performed vibration test of the TGMS, which was simulated by 6-axis shaking table. Through the vibration test, we analyzed the influence of vehicle vibration on the TGMS which will be installed on bogie frame. To the vibration test, two methods satisfied the required accuracy of track geometry measurement under the level of the actual vehicle vibration of HEMU-430X train. Theoretically, method A is sensitive to vehicle vibration than method B. However, HEMU-430X's bogie vibration frequency range is out of interest range of measurement system. Therefore, method A can also apply the HEMU-430X train.

Development of models for measuring track irregularities using accelerometers (가속도계를 이용한 궤도틀림 측정용 모델의 개발)

  • Lee, Jun-Seok;Choi, Sung-Hoon;Kim, Sang-Soo;Kim, Seog-Won
    • Proceedings of the KSR Conference
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    • 2011.10a
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    • pp.303-310
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    • 2011
  • This paper is focused on development of models for measuring lateral and vertical track irregularities from corresponding accelerometers of an in-service high-speed train. Generally, the track irregularity was measured by a special railway inspection vehicle or system with contact or non-contact sensors. However, the sensors are very expensive and vulnerable to a harsh environment. Displacement estimation from an inertial measurement unit and its wave-band filtering was already developed in the previous study, and it was found that their results included not only the track irregularities but also other information such as phase delay of the applied filters, and suspension and conicity of the wheel. To identify the track irregularities from those results, a compensation filtering method was proposed. Each directional compensation filter was derived by using a system identification method with the estimated directional displacement as input and the corresponding track irregularities as output. In this paper, they are integrated into a model for each direction and applied to the measured lateral and vertical acceleration data from the axle-box and bogie of an in-service high-speed train. Their results are compared with the data from the track geometry measurement system. From the comparison, the proposed models are a useful tool for the measurement of the track irregularities using accelerometers of in-service high-speed trains.

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Deformation Monitoring of Subway Track using by Automatic Measurement (자동화계측을 통한 지하철 궤도 변형 모니터링연구)

  • Jung-Youl Choi;Jae-Min Han
    • The Journal of the Convergence on Culture Technology
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    • v.10 no.1
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    • pp.579-584
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    • 2024
  • Currently, large-scale, deep construction is being carried out adjacent to subway tracks in korea. when excavating adjacent to each other, it is very important to ensure the safety of earth retaining structures and underground structures. therefore, we are managing the safety of the subway by introducing an automated measurement system. deformation of the subway track during adjacent excavation may affect train running stability. this is a factor that can be linked to train derailments. however, current subway track safety evaluation using automated measurement systems relies only on the maximum value of measured data. therefore, a method to improve the usability of automated measurement system results is needed. in this study, we utilized a technique that can quantitatively evaluate the measurement results of a large amount of subway track deformation. a safety evaluation was conducted on subway track deformation due to adjacent excavation using a vast amount of data using probabilistic statistical analysis techniques.

Continuous deformation measurement for track based on distributed optical fiber sensor

  • He, Jianping;Li, Peigang;Zhang, Shihai
    • Structural Monitoring and Maintenance
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    • v.7 no.1
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    • pp.1-12
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    • 2020
  • Railway tracks are the direct supporting structures of the trains, which are vulnerable to produce large deformation under the temperature stress or subgrade settlement. The health status of track is critical, and the track should be routinely monitored to improve safety, lower the risk of excess deformation and provide reliable maintenance strategy. In this paper, the distributed optical fiber sensor was proposed to monitor the continuous deformation of the track. In order to validate the feasibility of the monitoring method, two deformation monitoring tests on one steel rail model in laboratory and on one real railway tack in outdoor were conducted respectively. In the model test, the working conditions of simply supported beam and continuous beam in the rail model under several concentrated loads were set to simulate different stress conditions of the real rail, respectively. In order to evaluate the monitoring accuracy, one distributed optical fiber sensor and one fiber Bragg grating (FBG) sensor were installed on the lower surface of the rail model, the strain measured by FBG sensor and the strain calculated from FEA were taken as measurement references. The model test results show that the strain measured by distributed optical fiber sensor has a good agreement with those measured by FBG sensor and FEA. In the outdoor test, the real track suffered from displacement and temperature loads. The distributed optical fiber sensor installed on the rail can monitor the corresponding strain and temperature with a good accuracy.

Evaluation of Field Calibration Test on Rail for Train Wheel Force Measurement

  • Sim, Hyoung-Bo;Yeo, Inho
    • International Journal of Railway
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    • v.8 no.1
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    • pp.1-4
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    • 2015
  • An accurate measurement of the train-track interaction forces is important for track performance evaluation. In the field calibration test as a wheel load measurement process, the calibration system creates a different boundary condition in comparison with that in the train wheel passage. This study aims to evaluate a reliability of the field calibration test in the process of wheel load measurement. Finite element models were developed to compare the deformed shapes, bending moment and shear force profiles on the rail section. The analysis results revealed that the deformed shapes and their associated bending moment profiles on the rail are significantly different in two numerical simulations of the calibration test and the train wheel load passage. However, the shear stress profile on the rail section of the strain gauge installation in the field was almost identical, which may imply that the current calibration test is sufficiently reliable.

Measurement and analysis of support stiffness of the track which rubber ballast-mat installed (방진자갈매트구간 궤도지지계수 측정 및 분석)

  • Yang, Shin-Chu;Lee, Jee-Ha;Kim, Eun
    • Proceedings of the KSR Conference
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    • 2007.11a
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    • pp.1071-1076
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    • 2007
  • In high-speed line, at some part of the track which rubber ballast-mat installed, track irregularity grew rapidly and affected riding comfort and train running stability. It is urgently requested to establish counter-measures which can be applied to track under operation. To do this, it is very important to analysis the origin of that phenomenon before. Track support stiffness is an essential factor for evaluating track condition. Sudden changes of support stiffness along track occur instability of train and bad riding comfort. Preventing sudden changes of track support stiffness is a key technique in high-speed track maintenance. Besides the sudden changes, the magnitude itself also significantly affects track and train. Low stiffness of ballast-mat makes ballast acceleration area wider. And it may accelerate track irregularity growth. So, the stiffness should be limited. To calculate track stiffness, measuring load and displacement on track is needed. In this study, the behavior of the track which rubber ballast-mat installed was measured and analyzed to understand the origin of rapid growth of it.

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Evaluation of Stiffness Structure and Grouting Efficiency beneath the Precast Slab Track by Elastic Wave Tests (탄성파시험에 의한 프리캐스트 슬래브궤도의 강성구조와 충전성능 평가)

  • Lee, Il-Wha;Joh, Sung-Ho;Jang, Seung-Yup;Kang, Youn-Suk;Han, Sung-Woo
    • Proceedings of the KSR Conference
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    • 2007.11a
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    • pp.1303-1308
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    • 2007
  • Recently, precast concrete tracks are replacing ballast track for efficient and economic maintenance of track. Precast concrete railroad tracks are manufactured in factory, and transported to railroad construction site for installation. Therefore, quality of precast concrete track itself should be sufficiently good. On the contrary to the convenient manufacturing of precast concrete track, the installation of a precast concrete track requires careful steps. Typically, a precast concrete track is placed on an approximately 15-cm thick lean concrete layer. A mortar is filled between lean concrete layer and precast concrete track to adjust the sloping angle of a precast concrete track for a safe train operation at a curvy section. Then, the use of filled mortarproduces a void underneath a precast concrete track, which is harmful to structural safety of a precast concrete track undercyclic loading. Therefore, it is essential to make sure that there is no void left beneath a precast concrete track after mortar filling. In the continuous resonance method, the amplitude of frequency response measured using an instrumented hammer and an accelerometer is plotted against a pseudo-depth, which is half of the wave velocity divided by frequency. The frequency response functions are measured at consecutive measurement locations, 6-cm interval between measurement points, and then combined together to generate a 2-D plot of frequency response. The sections with strong reflections or large amplitude of frequency response are suspicious areas with internal voids and unfilled areas. The 2-D frequency response plot was efficient in locating problematic sections just by examining the color shade of a visualized plot in 2-D format. Some of the problematic sections were drilled to make a visual inspection of mortar filling. The visual image of interface between mortar and precast concrete track was verified using the validity of the continuous resonance technique adopted in this research.

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An Analysis of the Track Irregularity Progress on the Various Track System in Urban Transit (도시철도 궤도시스템별 틀림진전에 대한 분석)

  • Ko, Jae-Hyun;Kim, Man-Cheol;Lee, Jee-Ha;Cho, Jun-Gon;Park, Yong-Gul
    • Proceedings of the KSR Conference
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    • 2011.10a
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    • pp.311-319
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    • 2011
  • Track accompanies the process that track alignment by traffic loads is changed. A change of track alignment affects the running safety and riding comfort of train. This is called a track irregularity. The most important task in maintaining the track is to manage these track irregularity within quality parameters. Today, track maintenance of urban transit is enforcing immediate maintenance about section exceeding a safety standard by applying track recording data got through Integrated Measurement. This method is advantage of being easy of the maintenance assesment in case of the running safety, but is disadvantage of being difficult in case of the riding comfort of train. In this study, we propose track irregularity deviation of each track system depending on the time series and present about utilization plans of the Track Irregularity Progress Rate.

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Kinematic Modeling of a Track Trolley Using Extended Kalman Filter (확장 칼만필터를 이용한 궤도틀림 트롤리의 운동학적 모형화)

  • Lee, Jun S.;Choi, Il Yoon;Kim, Sun Hee;Um, Ju Hwan
    • Journal of the Korean Society for Railway
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    • v.18 no.5
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    • pp.447-456
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    • 2015
  • Continuous as well as discrete measurement of the track geometry based on a track trolley are investigated to enhance the efficiency of the trolley and to minimize the measurement errors. A new kinematic model based on the track coordinates involving transition and circular curves is developed to improve the accuracy of the measurement; a nonlinear Extended Kalman Filter (EKF) is employed to linearize the governing equations. The proposed model is verified with the ideal track geometry in terms of both discrete and continuous measurement. Comparison with the previous models is also made to prove the applicability of the kinematic model.