• Proceedings of the KSR Conference
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• 2010.06a
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• pp.989-995
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• 2010

This paper is focused on a simplified measurement of rail irregularity by some axle-box accelerometers for high-speed rail condition monitoring with in-service high-speed trains. Generally, the rail condition monitoring has been done by a special railway inspection vehicle with a 10m versine method. But, the monitoring method needs some expensive measurement system, and have been performed only at night due to its speed limit. In this research, a simplified measurement of rail irregularity using axle-box accelerometers is proposed to monitor the rail condition with in-service high-speed trains. The acceleration is measured by using two accelerometers on a axle-box, and stored in an on-board data acquisition system. The displacement is estimated from the acceleration data by a combination of Kalman filter and the frequency selective filter. The estimated results are compared with the measurement from a laser rail inspection system which is near the axle-box. From the comparison, the proposed method shows promise as a tool for the simplified measurement of rail irregularity at high-speed.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2012.10a
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• pp.797-798
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• 2012

• Journal of the Korean Society of Manufacturing Process Engineers
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• v.8 no.4
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• pp.136-142
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• 2009

The vehicle's light-weight technology is divided into optimization of structure geometric and material. Structure geometric optimization and improvement of materials has examined to be power-train and maintenance on the severe condition. The core technology of Special vehicle's light-weight is constitute by Drop box, Axle and Final reduction gear. Technology and product of the parts is high to overseas and import dependency. We will want to examine the possibility of light-weight for the Axle Case and Drop box-connections. In this research, conventional design of excess weight will inhibit the mobility and fuel efficiency. Through the improvement of Axle material, we saw the possibility reducing weight. If you use the results of these studies, it will be available to domestic production technology and reducing weight of RV car, Dump truck, Track crain, etc.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.65 no.4
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• pp.695-703
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• 2016

The maintenance method for the electrical facility of high speed railway has been evolved from inspection by personnel to the automated way by the detection devices. In particular, the signalling equipment in order to increase the safe and efficient operation of the trains is required to maintain normal operation by periodic maintenance. Because the return current gives the most important effects to the wayside equipment in case of the failures, a method is needed to measure the unbalanced rate of return current on the train at high speed driving. The Hot Box Detector(HBD) device that is installed at track-side has a function to recognize the abnormal axle box by detecting the temperature that occurs in the axle of train passing over its device. In order to implement the measurement equipment for unbalanced rate of return current and axle temperature, the design method is proposed and the experimental test results by test bed are included in the paper.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.18 no.1
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• pp.609-617
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• 2017

Railways are one of the safest and most important transportation systems in the world. On the other hand, due to the increasing complexity of the railway system and the running distance of rail vehicles, railway accidents occur continuously every year. In particular, in the case of high-speed trains and freight trains, if the function of the axle bearing is lost due to abnormal overheating of the axle box bearing, the load on the axle becomes uneven. Therefore, abnormal overheating in the train axle box bearings can cause serious accidents or derailments. For this purpose, a Hot Box Detector (HBD) was installed in the track side of a high speed line to detect abnormal overheating. This paper proposes an EWMA technique-based axle temperature monitoring method to detect abnormal overheating quickly and efficiently. A statistical design of the proposed method was also performed. The proposed method has better performance compared to the current method in the case of abnormal overheating and the performance is improved by approximately 170% at the maximum.

• Proceedings of the KSR Conference
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• 1999.05a
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• pp.116-123
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• 1999

A case of the axle gear box which was one of tile power transmission components of high speed train was supported by the bearings installed in axle and the reaction arm connected in bogie frame. Structural analyses of this case were executed for investigation the application of aluminum for weight reduction. The evaluations of the material strength, the thermal strength and deformation, and the stability of natural vibration were carried out according to computer simulation. It was found out that the steel case was safe from the structural failure. For the aluminum case, there was no worry about the vibration resonance and the static failure, but some efforts to reduce tile deformation of the bearing mounting part.

• Journal of the Korean Society of Safety
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• v.27 no.4
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• pp.43-49
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• 2012

In the design of high speed railway bridges is important a impact factor as a tool of assessing the dynamic capacitys of bridges. However, the impact factor(or dynamic amplification factor, DAF) of high speed railway bridges may essentially be changeable because the dynamic response is affected by the long train length(380 m), number of axles and high speed velocity(300 km/h)(Korea Train eXpress: KTX). Therefore, on this study will be examined the dynamic capacity and stability of the typical PSC Box Girder of high speed railway bridge. At first, the static/dynamic analysis is performed considering the axle load line of KTX based upon existing references. Additionally, the KTX moving load is transformed into the dynamic time series load for conducting various parameter studies like axle length, analytical time increment, velocity of KTX. The time history analysis is repeatedly performed to get maximum dynamic responce by varying axle load length, analytical time increment, velocity of KTX. The study shows that dynamic analysis has resonable results with optimal axle load length(0.6 m) and time increment(0.01 sec.) and maximum DAF and dynamic resonance happens at 270 km/h velocity of KTX.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.16 no.9
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• pp.6214-6220
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• 2015

A track circuit has used stably more than 100 years for detecting train position, but solution of track circuit sort circuit incapacity due to a rust is necessary for side line in station yard, coast line and level crossing for conventional line in rural line. Domestically, Axle Counter System(ACS) has partially used for Hot Box System for high speed line and turnout for CBTC system. In contrast, most of countries has used ACS not only trunk line but also rural line and its application has increased for metro, electric car and industrial railway. In this paper, we has verified the operating status of ACS which installed with existing track circuit through log analsis to implement pilot application in mail track and turnout in station yard. And interface test with interlocking system has conducted at Obong shunting yard, as well as Cheongju station and has analyzed test result. Based on a test result, we made fail safe design, manufacturing skill and established system requirement specification for the smooth operation and maintenance.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2010.05a
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• pp.385-386
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• 2010

• Proceedings of the KSR Conference
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• 2011.05a
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• pp.427-434
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• 2011

This paper is focused on application of recursive least squares method to estimate rail irregularities from the acceleration measurement on an axle-box or a bogie for the rail condition monitoring with in-service high-speed trains. Generally, the rail condition was monitored by a special railway inspection vehicle but the monitoring method needs an expensive measurement system. A monitoring method using accelerometers on an axle-box or a bogie was already proposed in the previous study, and the displacement was successfully estimated from the acceleration data by using Kalman and frequency selective band-pass filters. However, it was found that the displacement included not only the rail irregularities but also phase delay of the applied filters, and effect of suspension of the bogie and conicity of the wheel. To identify the rail irregularities from the estimated displacement, a compensation filter method is proposed. The compensation filters are derived by using recursive least squares method with the estimated displacement as input and the measured rail irregularity as output. The estimated rail irregularities are compared with the true rail irregularity data from the rail inspection system. From the comparison, the proposed method is a useful tool for the measurement of lateral and vertical rail irregularity.