• 한국철도학회:학술대회논문집
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• 한국철도학회 2011년도 춘계학술대회 논문집
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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.

• 한국철도학회:학술대회논문집
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• 한국철도학회 2010년도 춘계학술대회 논문집
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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.

• 한국항해항만학회지
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• 제45권6호
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• pp.346-351
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• 2021

국토교통부에서 화물 차주의 과로, 과적, 과속을 근절하려는 목적으로, 2020년도부터 '화물자동차 안전운임제'가 시행 되었다. 컨테이너 및 BCT(시멘트) 품목의 '화물자동차 안전운임'은 금액이 구체화 되었고, 위반시 과태료를 부과하며 강제성 있게 시행되었으며, 2021년에는 각 항목별 조정율이 적용되어 보완되어가고 있지만, 일반형 화물자동차(카고) 및 철강재 품목의 '화물자동차 안전운송원가'는 아직 원가 구성 항목 및 금액이 논의 중이어서 권고 형태로만 적용 중이다. 본 연구는 일반형 화물자동차 최대적재량 톤수별 독차 운임에 대하여, 화물 운수 실무자들의 지불의사를 추정하는 것이 목적이다. 화주, 운수사(주선사, 운송사), 차주(지입, 개인)를 대상으로 조건부가치측정법(CVM) 중개방형 직접질문법으로 설문조사를 실시하였고, 각 응답자로부터 수집된 데이터를 활용하여, 토빗(Tobit) 회귀분석을 하였다. 분석을 통해 지불의사에 영향을 주는 유의 변수(현재 운송료 만족도 등)들을 확인하였다. 그리고 추정된 결과를 활용해 화물 운임의 평균값, 중앙치를 도출하여 화물차 톤수별 지불의사금액를 각각 확인하였다. 본 연구의 결과가 '화물자동차 안전운송원가' 심의·의결 기관인 '화물자동차 안전운임위원회'에 참고 자료로 활용되어, 제도가 원활하게 정착되어 도입 될 수 있기를 기대한다.

• 한국철도학회논문집
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• 제16권2호
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• pp.138-143
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• 2013

최근 철도수송 물동량은 점진적으로 줄어드는 추세이며, 특히 무개차의 수송량이 크게 줄어드는 경향을 보이고 있다. 무개차는 덮개가 없는 화차로서 용도에 따라서 일반 무개차, 호퍼차, 자갈차로 분류할 수 있으며, 이 중에서 일반 무개차를 가장 많이 보유하고 있다. 일반 무개차는 2001년 전체 화차수송횟수의 약 23.3%를 차지했지만 2010년에는 14.5%로 그 역할이 많이 축소되었다. 최근에는 일반 무개차를 컨테이너 수송 용도로도 활용하고 있으며, 벌크화물을 컨테이너차로 수송할 수 있는 다양한 용기가 개발되고 있어 장기적으로 일반 무개차의 수요는 줄어들 것으로 판단된다. 그러나 일반 무개차는 여전히 철도수송에서 벌크시멘트차, 컨테이너차 다음으로 중요한 역할을 수행하고 있으며, 장기적인 관점에서의 수요 감소에 대비한 운용 방안의 수립이 필요하다. 본 연구에서는 일반 무개차의 효율성을 분석하고 향후 일반 무개차의 운용 방안 수립을 위한 방향을 제시하였다.

• 한국철도학회:학술대회논문집
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• 한국철도학회 2003년도 추계학술대회 논문집(III)
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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.

• 한국기계가공학회지
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• 제17권1호
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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.

• 한국철도학회:학술대회논문집
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• 한국철도학회 1999년도 춘계학술대회 논문집
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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.

• 대한기계학회:학술대회논문집
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• 대한기계학회 2001년도 춘계학술대회논문집B
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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.

• 한국철도학회논문집
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• 제9권6호
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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.

• 한국기계가공학회지
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• 제18권2호
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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.