• Proceedings of the KSR Conference
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• 2011.05a
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• pp.263-268
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• 2011

There are many exclusive freight cars in railway freight transportation system. Gondola is one kind of freight cars. Gondolas have a role to carry bulk-type cargo such as coals and ores. A few problems are occurring due to exclusive freight cars. Operation company has redundant freight cars because exclusive freight cars can carry limited items. And purchasing cost of freight cars is higher and higher because of irregular bid. Operation efficiency of gondola is very low because return time of gondola is much longer than that of container car. In this study, we analysed the introduction effect of hopper-type container for through transit. First, we identified the characteristics of spatial distribution on freight stations. And we provided the effect of hopper-type container in terms of operation efficiency, cost reduction, new demand excavation and image enhancement of eco-friendly railroad.

• Proceedings of the KSR Conference
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• 2010.06a
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• pp.1542-1548
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• 2010

Transportation cost takes a major portion on logistics cost. The reduction of transportation cost is a key issue to achieve national competitiveness and logistics cost reduction. And railway must play a important role to shift from road freight transport to environment-friendly transport. There are many idle freight cars in railway freight transportation and they give rise to inefficient operation of freight car. It is well known that the main reason of idle freight cars is unbalanced demand according to direction. In this study, we analysed the current status on idle freight cars in railway at the level of daily data. This results help follow-up research to cut down idle freight cars in railway.

• Journal of Navigation and Port Research
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• v.45 no.6
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• pp.346-351
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• 2021

With the goal of eradicating overwork, overload, and speeding of general freight cars(cargo) by the Ministry of Land, Infrastructure and Transport, Infrastructure and Transport, the "The Fare of safe transportation for freight cars System" has been enforced since 2020. 'The Fare of safe transportation for freight cars' rate for each item is being applied and supplemented, but the 'The Cost of safe transportation for freight cars' of general freight cars (cargo) and steel items is under discussion. The purpose of this study was to estimate the willingness to pay( WTP) for cargo. A survey was conducted on shippers, transportation companies (arrangers, carriers), and cargo drivers (using direct questioning among contingent valuation method (CVM) and the Tobit Regression analysis was conducted, and the average and median values of freight rates were derived using the estimated results, and the willingness to pay by tonnage of freight cars was confirmed. It is expected that the results of this study can be used as a reference to the "The Fare of safe transportation for freight cars Committee" an organization for deliberation and resolution of the 'The Cost of safe transportation for freight cars'.

• Journal of the Korean Society for Railway
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• v.16 no.2
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• pp.138-143
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• 2013

Recently, the demand for rail freight has gradually decreased. In particular, the demand in Korea for open freight cars, which classification includes gondola cars, hopper cars and gravel cars has been significantly reduced. The role of gondola cars in the rail transportation market shrank to 14.5% in 2010 from 23.3% in 2001. The transportation demand of gondola cars in the long term is expected to be reduced further. Because some gondola cars have been converted to container cars and various containers are being developed to transport bulk cargo by container cars. However, gondola cars still play an important role in rail freight transport. Therefore, the management planning of gondola cars is needed in order to prepare for the long-term declining demand. In this study, we propose a future direction for the management planning of gondola cars through the effectiveness analysis of gondola cars operation.

• Proceedings of the KSR Conference
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• 2003.10c
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• pp.109-113
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• 2003

Recently, freight cars for diverse purposes were developed to increase the speed of freight car in conventional line. The welded type bogies are applied to these vehicles like container car, gondola car, hopper car, etc. This study was focused on the dynamic characteristics and the stability of freight car to guarantee the running safety. We have conducted the running tests of freight cars in conventional line and described the test results in this paper.

• Journal of the Korean Society of Manufacturing Process Engineers
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• v.17 no.1
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• pp.130-137
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• 2018

In long freight trains, there is a brake time delay in the neighboring freight cars that causes damage and fractures of couplers, especially the knuckle of them. If there is a problem for couplers in the cars, this could cause a derailment and lead to damage of human life and property damage. In this study, maximum forces on the couplers are studied when a long freight car brakes, with brake delay time and coupler gap. We have made a dynamic model of 50 freight cars and couplers, applying contact between couplers and a characteristic curve for expressing force and displacement of buffers with SIMPACK, a multi-body dynamics program. We use EN 14531-2 from the British Standards Institution, a standard of freight car brakes for the verification of the dynamic model. We also use a simplified method to analyze the dynamic model of 50 freight cars. With changing coupler gap and brake delay time, we do comparative analysis with AAR M-201 from the Association of American Railroads, a standard of AAR couplers. From this result, we find that the standard on fatigue limit is satisfied, such that the brake delay time is within 0.06 second if the coupler gap of the AAR coupler is within 20 millimeters.

• Proceedings of the KSR Conference
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• 1999.05a
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• pp.110-115
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• 1999

Experimental study is conducted to clarify the pneumatic characteristics of brake system for freight car. KNR(Korean National Railroad)'s freight cars have the laden-tare type control valve of brake system. But, laden-tare type control valve has some shortcomings to match the high speed freight car. Newly developed diaphragm type control valve is introduced to adopt freight car for speed-up. The test using the formated train set consisted of 21 cars is conducted to estimate the pneumatic braking efficiency of the mixed train set. From the results of experiment, the pressure characteristics of each brake cylinder show similar patterns qualitatively. But, in the case of release and brake application, quantitative pressure values of brake cylinder are different.

• Proceedings of the KSME Conference
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• 2001.06b
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• pp.525-532
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• 2001

Experimental study has been conducted to clarify the pneumatic characteristics of brake system for freight train and enhance the performance of diaphragm valve. Empty-load and diaphragm brake systems are mainly used in the freight trains of KNR (Korean National Railroad). The train set is composed of thirty freight cars and diesel locomotive. From the experimental results, new quick release valve shortens release time after brake application. In case of normal brake application, the release time is short by 34% of that of original diaphragm control valve. It will be expected to assure brake-release application and reduce maintenance efforts.

• Journal of the Korean Society for Railway
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• v.9 no.6 s.37
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• pp.630-634
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• 2006

Rail car axles are very important parts for safety of passengers and structural integrity of vehicles. The axles are supported by bearings. To seal grease lubricating the bearings of freight cars, an oil seal has been developed. The developed oil seal is composed of an inner plate, an outer plate and a seal rubber. The friction between axle and housing with the developed oil seal is very low. The seals are designed for a minimum life expectancy of 800,000 kilometers service. In this study, an accelerated durability tests according to AAR Specification M-934-82 were carried out. In addition, various performance tests according to KS B 2804 were conducted.

• Journal of the Korean Society of Manufacturing Process Engineers
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• v.18 no.2
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• pp.65-72
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• 2019

In long freight trains, there is a brake time delay in neighboring freight cars, which causes damage and fractures in the couplers, especially at their knuckle. A problem in the couplers of the cars can cause derailment and damages of human life and property. In this study, maximum forces on the couplers are studied when a long freight car brakes with the brake delay time and coupler gap. We make a dynamic model of 50 freight cars and couplers, applying contact between the couplers and a characteristic curve to express the force and displacement of the buffers using SIMPACK, which is a multi-body dynamics program. We use EN 14531-2, which is a standard of freight car brakes, to verify the dynamic model. Then, we compare the analyzed impact force with the coupler knuckle standard after applying the two carriages of a locomotive in the model based on the dispersed double head control system. The result shows that all coupler gap conditions satisfy the infinite lifetime of the material when the brake delay time is 0.1 second.