• Proceedings of the KSR Conference
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• 2011.05a
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• pp.377-383
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• 2011

The paper is to perceive accurately speed of the train through redundant processor operation. When Slip/slide is occurred at the axle, the train is applied brake force using the Tachometer and the Doppler sensor which assistance equipment. One of the main features of railway signaling system is that rolling stock is made stop to avoid collision with the rolling stock ahead when the rolling stock exceeds its maximum operating speed in line. In addition, in the case of the rolling stock with automatic train operation, it carries out activities such as braking and propulsion using the difference between its actual speed and target speed at the point. To perform these functions, it is essential to calculate the exact speed of the rolling stock in signaling equipment on vehicles. Train speed detection unit are composed of the Tachometer and the Doppler sensor, and speed information is sent to the SDU unit. The processor of SDU unit calculates the speed of the train using compare logic the received speed information. Even if there are Slip/Slide, signaling system is available to apply exact braking, to improve stop on position and to guarantee the safety of trains.

• Transactions of the Korean Society for Noise and Vibration Engineering
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• v.16 no.2 s.107
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• pp.156-162
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• 2006

For the reduction and efficient management of railway noise, first of all prediction of railway noise is necessarily requisited. Many studies for prediction of railway nearby noise have been accomplished. But it is impossible to predict easily and exactly for the Korean Railway, because the acoustic powers for each rolling stock operated in Korea have not been built yet. So in this study, Prediction model equation for environmental noise for Korean rolling stock Saemaeul was suggested using SEL of engine and rolling noise component separately. Finally for the validation of prediction equation, the predicted result was compared to the measured.

• International Journal of Railway
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• v.4 no.2
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• pp.42-49
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• 2011

Today, rolling stock has become a fast and convenient mode of transportation and has witnessed increased demand. But the speed improvement has resulted in increased aerodynamic noise and therefore residential districts near the railroad tracks are exposed to ever increasing noise level. A study on methodologies for measuring and appraising rolling stock's environmental noise has therefore become an important area of endeavor. In the case of the environmental noise, there are no changes in tone so prediction can be made by reducing areas around the railway. The present study explores estimation of the noise around the railway using scale model, and the source of the noise has been investigated as well. The scale model of rolling stock will have to be able to measure high frequency noise and it is required to be generated in a short amount of time. Since popping a balloon or firing a gun fits this requirement the present study analyzed the characteristics of these two different noise sources. Measurement was made in a large vacant lot and the reflection due to the ground was also examined. The method proposed here can be used in the future for predicting the environmental noise of railway vehicles.

• Proceedings of the KSR Conference
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• 2008.06a
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• pp.806-812
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• 2008

Many kinds of rolling-stocks that have various control methods are being operated by Seoulmetro which is a history of a city railroad rolling-stock. Seoulmetro is being faced with a wheel management comparing of other lines with a perpendicular wear of wheel and a side damage, and so on, by operating several cars at a loop line. This is causing maintenance expenses increase and deteriorating a fusibility of rolling-stock, for it has an effect on a rolling-stock using. A cutting pattern of wheel and a wear form affect the expected span of a wheel. A wheel cutting cause is classifed into cutting for reprofiling of a flange wear of wheel and for removing every kind defect which originates from wheel wear. In this study, Seoulmetro exhibit a stable rolling-stock use method and a reasonable management method of wheel, analysing wheel exchange condition and cutting management of wheel.

• Journal of the Korean Society for Railway
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• v.9 no.5 s.36
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• pp.555-560
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• 2006

This study finds out and suggests success factors for the application of RIMS project through the case study of Seoul Metro and literature survey. The successful application of RIMS needs expert knowledge and concept of BOM, standardization of maintenance planning, check lists of heavy maintenance inspection, organization structure of rolling stock maintenance offices, material management system of warehousing and the process of parts repairing between offices, connection of material ordering system, problem solving of circular spare parts administration among inspection, maintenance, and material organizational units, systemic serial number management of parts with RFID, daily closing diary connected with work process chart, and sufficient period of RIMS's test run. RIMS contributes to real time management of rolling stock maintenance, transparency of management, reliability of train operation, customer satisfaction, and management innovation.

• Journal of the Korean Society for Railway
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• v.9 no.6 s.37
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• pp.798-803
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• 2006

The suspension elements like primary coil spring, yaw damper, body to body damper are core parts of high speed railway bogie and the faults relating to these elements are reported recently. Thus, this study is started to analyze the displacements characteristics of suspension elements of high speed railway rolling-stock for the purpose of preventing the faults and developing the maintenance technology for suspension elements like spring and dampers. For this purpose, we made a plan to measure the displacements of the primary coil spring, yaw damper and body to body damper in actual running condition. We developed the measurement device to measure the longitudinal displacement and angular displacement of suspension elements and installed this device to test suspension elements. Test to measure displacements of suspension elements is conducted in service line of high speed railway. The displacement data which is acquired from the test with actual vehicles was analyzed for its maximum displacement depending on the track sections. As a result of analysis, we obtained the displacement trends occurring with the sections and valuable results like maximum values and the displacement distribution.

• Proceedings of the KSR Conference
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• 2010.06a
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• pp.810-815
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• 2010

Since a long time ago, many railway engineers analyze and discuss the interface between the sub-system of railway, such as a wheel/rail interface, pantograph/catenary interface etc. The verifying of the system interface could help to achive the optimized performance and safety of the railway system considering that the railway system is constructed by various engineerings, such as civil, mechanical, electrical, etc. A rolling stock with distributed drive system, which will be developed by HEMU-400x project, is capable of running on high speed line and conventional line in Korea. To verify the performance of rolling stock, test run will be done with revenue service line. And the test items of the system interface have to be selected to verify a functional compatibility and physical force between rolling stock and infrastructure. In this paper, the authors will indicates the test items to verify system interface. To achive the conclusion, the authors analyze a specification of the development train and the design value of Seoul-Busan high speed line, which will be used for testing of the development train, and also, study the various case of high speed train commissioning.

• Journal of the Korean Society of Safety
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• v.31 no.3
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• pp.28-33
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• 2016

Since defects in the wheels of railway vehicles, which occur due to wears with the rail, cause serious damage to the running device, the diagnostic monitoring system for condition-based maintenance is required to secure the driving safety. In this paper, we studied to apply a useful Cepstrum analysis to detect periodic structure in spectrum among the vibration signal processing techniques for the fault diagnosis of a rotating body such as wheel. In order to analyze in variations of train velocity, the Cepstrum analysis was performed after a domain change of the vibration signal from time domain to rotation angle domain. When domains change, it is important to use a interpolation for a uniform interval of the rotation angle. Finally, the Cepstrum analysis for wheel flat detection was verified by using the vibration signal including the disturbance resulting from the rail irregularities and the vibration of bogie components.

• Journal of the Korean Society for Railway
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• v.7 no.2
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• pp.93-98
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• 2004

For the reduction and efficient management of railway noise, first of all prediction of railway noise is necessarily requisted. At home and abroad many studies for prediction of railway nearby noise have been accomplished. But it is impossible to predict exactly for the Korean Railway, because the acoustic powers for each rolling stock used in Korea have not been built yet. So in this study, acoustic powers for each Korean rolling stock such as Samaeul, Mugungwha were builded acceding to the speed and rail support systems. Predicted results using the acoustic powers suggested in this study are compared with measured results and it is known that these acoustic powers can be used for precise prediction of railway noise.

• Journal of the Korean Society for Railway
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• v.11 no.3
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• pp.233-239
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• 2008

It is very important to set a reliability target and verify the requirement when procuring the rolling stock in the aspect of safety, availability and LCC. While there are a few different methods to verify the reliability target, it is required that the most appropriate method should be used considering the characteristics of rolling stock itself and the operation environment. Even though recently the quantitative reliability requirements are widely adopted in domestic market, there is no substantial contents in the various standards and guidelines. In this study we investigate the various reliability demonstration test plans and evaluate them for rolling stock application. And three test plans among them were applied to the real operation data.