• Journal of the Korean Society for Railway
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• v.9 no.4 s.35
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• pp.461-466
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• 2006

In order to transport cargo rapidly and safely from the trans-Korean railway to the trans-Siberian railway having a different gauge, a gauge-changeable freight wagon can be used. Because the wagon is expected to run in South Korea, North Korea and Russia, it should have good dynamic performance in these railways. In this paper, the dynamic characteristics of a gauge-changeable freight wagon was analyzed numerically using ADAMS/Rail in each condition of the railways having different gauges and rail profiles. The wagon makes use of load sensitive friction damping and has highly nonlinear behaviour, which is modeled in detail as the full nonlinear dynamic model. It is shown that the running behaviour of the wagon is sensitive to changes in the rail gauge and profiles, however the assessment quantities from the point of view of safety, track fatigue and running behaviour are less than the limit valves.

• Proceedings of the KSR Conference
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• 2000.11a
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• pp.484-490
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• 2000

The freight wagon with weld fabricated 1-piece bogies, which was developed to increase operating speed, reveals its difficulties in maintenance. The weld-fabricated bogies were composed of two-stage coil spring and dry friction damping mechanism. The inborn wear parts and rather complicated structure mattes bogie maintenance difficult. In order to relieve this difficulties, the application of maintenance free rubber suspension is proposed by bogie maunfacturer, Taeyang Precision Limited. This study was conducted to determine design parameters of proposed rubber suspension by means of vehicle dynamic simulation and parametric study. The target critical speed of bogie was set over 150km/h for the preparation of further speed-up of freight wagon.

• Journal of the Korean Society for Railway
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• v.7 no.1
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• pp.49-54
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• 2004

Particularly derailing freight wagon, which are loaded with dangerous chemicals, has large damages on humans and environment. In this paper the dynamic characteristic of the laminated leaf spring under extreme situation, for example derailment, is examined. The leaf spring has a static hysteresis. Not only the friction value, but also the spring rate are influenced by this hysteresis characteristic. Because of the static hysteresis of the leaf spring the spring rate must be used in normal operation depending upon the loading and the kind of the excitation with the up to 10-fold value of the static spring rate. Some characteristics of the leaf spring can be treated like well-known viscous damping, but fer special situation (preload and/or excitation) particular calculation are necessary.

• Proceedings of the KSR Conference
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• 2006.05b
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• pp.227-232
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• 2006

• Journal of Mechanical Science and Technology
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• v.19 no.7
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• pp.1469-1477
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• 2005

Vibrations related to ride comfort should be considered at the beginning of design stage. In general, ride comfort of human is mainly affected by vibration transmitted from the floor and seat. Also, vibration level is very important regarding with running safety on freight wagon. To ensure ride comfort for passenger coach and vibration level for freight wagon, tests had been repeated by different test procedures with several equipments. With different measuring and evaluations for these results, it took much time to evaluate test results. In this paper, a new evaluation procedure was developed combining several software for ride comfort and vibration level test on railway vehicles. In addition, this developed system is capable of ride comfort test and vibration test by a single integrated system that is capable of immediate reporting the test result. With this developed system, the comfort in a passenger coach and the vibration in a freight car were evaluated. And the simulation results from the proposed system are verified by a field test.

• Proceedings of the KSR Conference
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• 2008.11b
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• pp.1642-1645
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• 2008

It is said that the effect in wheels of freight car varies with the type of freight, the condition of operation, the braking device, and the type of bogie. The hardness of open wagon, gondola car, propylene car, covered freight car, container car and hopper car has been measured according to the mileage through this research. As a result, the wheel with more mileages after shaving off the wheel tread has a higher hardness than the others in the case of same type of car.

• Proceedings of the KSR Conference
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• 2008.11b
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• pp.1607-1613
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• 2008

The present investigate is a base investigate required in development of DMT wagon train. And it deduced that follows by developing trail analysis model about Modalohr wagon train and examining traveling movement specific using analysis model developed. Vibration acceleration of all direction was increased with addition of travel speed and first suspension. But in case of right and left vibration acceleration, that could influenced by nonlinear specific of first suspension. Therefore checking about those is needed. Frequency of $2{\sim}3\;Hz$ and $7{\sim}8\;Hz$ generated in Right and left, up, down vibration of vehicle. And right and left vibration of bogie generated $25{\sim}35\;Hz$ in low speed section and frequency of $40{\sim}50\;Hz$ in high speed section, $25{\sim}35\;Hz$ in low speed section, $10{\sim}15$ or $40{\sim}50\;Hz$ in high speed section.

• Proceedings of the KSR Conference
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• 2010.06a
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• pp.432-436
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• 2010

This paper investigates the productivity growth in Korean railway lines. The productivity growth is calculated by a process of measuring of pure efficiency change index(PECI), scale efficiency change index(SECI), and technical change index(TCI), using Data envelopment analysis (DEA) method. The data cover the period 1990~2007; 1990~2003 are the pre-structural reform years and the post-structural reform years are 2005~2007. The framework for the analysis is Malmquist Productivity Index (MPI) of the to investigate the impacts of structural reform on productivity growth, respectively. The inputs considered are the length of operating line, the number of staff, the number of coach and wagon, and the outputs are the trains movement of passenger and freight, and the traffic of passenger and freight.

• Proceedings of the KSR Conference
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• 2009.05a
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• pp.378-381
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• 2009

This paper investigates the productivity growth in Korean railway transport. The productivity growth is calculated by a process of measuring of pure efficiency change index(PECI), scale efficiency change index(SECI), and technical change index(TCI), using Data envelopment analysis (DEA) method. The data cover the period 1999$\sim$2006; 1999$\sim$2003 are the pre-structural reform years and the post-structural reform years are 2004$\sim$2006. The framework for the analysis is Malmquist Productivity Index (MPI) of the to investigate the impacts of structural reform on productivity growth, respectively. The inputs considered are the length of operating line, the number of staff, the number of coach and wagon, and the outputs are the trains movement of passenger and freight, and the traffic of passenger and freight. Results indicate that Korean railway experienced a annual productivity growth of approx. 3% after the structural reform.

• Journal of the Korean Society of Manufacturing Technology Engineers
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• v.26 no.4
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• pp.436-440
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• 2017

This study evaluated the design and structural integrity of a three-axle bogie frame in a railway freight car through a numerical analysis and an experimental evaluation. A three-axle bogie frame, which supports the weight of the car body and load, is required to transport heavier cargo because two-axle vehicles have structural limitations. Therefore, this study performed a structural analysis and static load tests to evaluate the design and structural integrity of a three-axle bogie frame. The results obtained from the numerical analysis were compared to those of the experiments. For the bogie frame used in the experiments, a failure evaluation was performed using non-destructive methods. The numerical analysis and experimental evaluation were satisfactory for the structural integrity evaluation.