• The Journal of the Convergence on Culture Technology
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• v.8 no.5
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• pp.547-552
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• 2022

In this study, shape-based track management by analyzing track irregularity was studied in terms of force-based track irregularity analysis by numerical analysis of wheel-rail interaction force using by the measured vertical irregularity. The effect of the vertical irregularity of the track due to the difference in track types on the wheel-rail interaction force and the track acceleration in the connecting section of the sleeper floating track and the direct fixation track on concrete bed were analyzed. As the results of this study, the measured vertical irregularity was directly affect the vertical wheel load (the wheel-rail interaction force) and the rail acceleration, and it has been demonstrated to change consistently. In this study, the adequacy and necessity of the force-based track irregularity analysis method was verified based on the wheel-rail interaction analysis using the the measured vertical irregularity.

• Journal of the Korean Society for Railway
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• v.18 no.1
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• pp.1-7
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• 2015

Maintenance and repair devices used for the inspection of the main parts of domestic railway vehicles have been imported from abroad. Especially, one of the representative domestic devices, the 'Wheel Profile Inspector System (WPIS)', was made by benchmarking foreign devices; this vehicle has been operated in the field. However, problems such as the reliability and performance of the WPIS in operation have appeared. In this study, in order to improve the precision and reliability of the WPIS for maintenance and inspection of railway vehicle wheels, the researchers improved the railway vehicle's WPIS by applying high-speed vision camera technology and an optimized image algorithm. The test results show that the reliability of the developed WPIS improved by approximately 10.4% compared to that of the conventional system.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.17 no.7
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• pp.175-181
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• 2016

This occurs when the unbalanced rotating body is inconsistent with the mass center line axis geometric center line. Wheelsets are assembled by a single axle with two wheels and a rotating body of a running railway vehicle. Owing to non-uniformity of the wheel material, the wear, and error of the wheel and axle assembly may cause an imbalance. Wheelsets will suffer the effects of vibrations due to the unbalanced mass, which becomes more pronounced due to the thin and high-speed rotation compared to the shaft diameter This can affect the driving safety and the running behavior of a rail car during high-speed running. Therefore, this study examined this unbalanced wheel using a railway vehicle multibody dynamics analysis tool to assess the impact of the dynamic VI-Rail movement of high-speed railway vehicles. Increasing the extent of wheel imbalance on the analysis confirmed that the critical speed of a railway vehicle bogie is reduced and the high-speed traveling dropped below the vehicle dynamic behaviour. Therefore, the adverse effects of the amount of a wheel imbalance on travel highlight the need for management of wheel imbalances. In addition, the static and dynamic management needs of a wheel imbalance need to be presented to the national rail vehicles operating agency.

• Proceedings of the KSR Conference
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• 2003.05a
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• pp.656-662
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• 2003

The rolling-stocks used in conventional line have suffered wheel problems due to lack of adaptability with track. These brought out severe wheel wear and inefficiency of wheel maintenance. Especially, tight wheel maintenance criteria have caused waste factors of wheel machining, these increases rolling-stock maintenance costs. Thus, this study was started to Propose the wheel maintenance plans to improve maintenance efficiency in respect to wheel maintenance process in rolling-stock workshop. Here, we describe some results

• Journal of Korean Society of Forest Science
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• v.108 no.3
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• pp.322-328
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• 2019

The purpose of this study was to provide basic data for maintenance and repair of the forest road surfaces using the light drop weight test (LDWT), density test, and grain size analysis at four sites in Yeongyang-gun Mt. (2011y, 2014y, 2016y, and 2017y). In terms of the density test results, the opening density in 2011 was the highest at $2.0694g/cm^3$, and the opening density in 2017 was the lowest at $1.7443g/cm^3$. The grain size analysis showed that the proportion of large aggregates was highest at the opening in 2017, and the proportion of large aggregates decreased with the delay of opening date. From the LDWT results, $E_{vd}$ (the dynamic deformation coefficient) of the 2011y forest road was $35.7MN/m^2$, 2014y was $30.5MN/m^2$, 2016y was $28.6MN/m^2$, and 2017y was $23.5MN/m^2$. The $E_{vd}$ value for the oldest forests opened with the 2011y forest road was the highest, the average $E_{vd}$ value of the center portion was $21.45MN/m^2$, the average $E_{vd}$ value of the wheel portion of the banking part was $31.31MN/m^2$, and the average $E_{vd}$ value of the wheel portion of the cut part was $36.71MN/m^2$.

• Journal of the Korea Society for Simulation
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• v.30 no.1
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• pp.127-137
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• 2021

The method of utilizing the strain and vibration values of rails is primarily used to diagnose the condition of wheels and railroad facilities. The dynamic load is measured under the assumption that the strain of the rail and the load of the railroad vehicle are proportional. Wheel condition is measured under the assumption that the magnitude of the defect and the magnitude of the rail vibration are proportional. However, environmental factors affecting the strain and vibration of the rail such as vehicle speed, wheel load, climate, and track conditions are not reflected, many errors occur depending on the measurement conditions. In this study, the effect of track distortion, which is a major indicator of the track condition among the environmental factors that affect the strain and vibration of the rail, on the strain and vibration of the rail, was examined through dynamic simulation. As a measure to reduce the measurement deviation, the effect of securing additional measurement points was analyzed.

• Proceedings of the KSR Conference
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• 2007.05a
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• pp.1344-1368
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• 2007

The Advanced countries including Japan, USA and European countries are adopting automatic system(e.g., auto-measurement using CCD camera) for measuring pantograph sliding plate and wheel abrasion to minimize manpower for E.M.U(Electric Multiple Unit) inspection and maintenance as part of management rationalization of railroad Corporation since late 1980's. In Korea, as part of scheme of business rationalization, automatic system for measuring pantograph sliding plate and wheel abrasion started to draw industry attention since late 1990s, and the system started to be installed in newly built depots of Korea Railroad Corporation since 2002. This study hopefully provides the base for realizing business rationalization and applying the advanced technology developed by Korea, the country of powerful IT basis, to overseas railroad organizations by examining automatic system for measuring pantograph sliding plate abrasion using existing CCD cameras produced domestically and in foreign countries to study cases(organizations in Korea) for improvement of measurement, management and inspection of pantograph sliding plate abrasion using CCD cameras with new cutting-edge technology; and by applying the study result to railroad organizations in metropolitan areas in Korea.

• Proceedings of the KSR Conference
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• 2008.11b
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• pp.666-672
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• 2008

Train wheels are the most important part of the high-speed rail system with supporting body, running stably and safely. Wheel exchange and fix plan is computed by the worker who managing entire Train Maintenance Process based on his know-how so that this system is losing its reliability and accuracy. And predicting of the wheel's lifetime is absolutely difficult matter because of uncertainty between trains like mileage of the type of trains, condition of operation, curve section and wheel's cutting pattern. Therefore workers always used to hold many wheels. For this reason, the cost of stock is soar when the level of stock was normal. If the stock is sufficient, the cost of stock will rise. On the other hand, If the stock is deficient, we would have trouble that the plan of the train maintenance process will be failed. Thus this paper aimed at application that "Wheel Managing System" which is able to predict wheel's life-cycle and demands under the RIMS(Rolling-Stock Information Maintenance System) with analysing wheel exchanging and cutting status considering economical or stable aspects.

• Proceedings of the KSR Conference
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• 2002.05a
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• pp.404-410
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• 2002

In this study, we have analyzed the optimum control of wheel for coach car in maintenance process to grasp the problem relating to this coach's wheel exchanged. So, these problems brought about decrement maintenance cost. This study were deliberated to solve problems concerning maintenance process of wheel exchanged and wheel specification in rolling stock workshops of KNR. Here, we describe some results.

• Journal of the Korean Society for Railway
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• v.4 no.4
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• pp.8-14
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• 2001

레일의 이음매부는 상시 차륜에 의한 충격ㆍ진동이 크기 때문에 이음판ㆍ볼트의 이완, 레일 단부의 변형ㆍ손상, 도상 자갈의 파괴ㆍ세립화의 발생 등 궤도 관리상의 최약점 개소로 되어 있다. 지금까지 이와 같은 이음매부를 줄이기 위하여 수송밀도가 높은 주요 간선에 대하여 용접에 의한 레일의 장대화가 진행되고 있으며, 또한 구조물 주변의 보수가 곤란한 개소 및 도시 구간에서의 소음ㆍ진동 대책뿐만 아니라 궤도 보수 작업의 경감과 열차의 고속화ㆍ승차감의 개선 등에 레일 용접이 크게 공헌하고 있다. (중략)