• Journal of the Korean Society for Precision Engineering
• /
• v.33 no.4
• /
• pp.317-324
• /
• 2016

Stress tests were conducted in the carbody of the railroad car to check the structural strength of the body of the railroad car. The objective of this study was to evaluate safety of the carbody of a railroad car under the maximal strength. The carbody of rolling stock is a principal structure that supports major equipment of the underframe and the freight. Therefore, the strength evaluation of this structure is important. This study was carried out to analyze the structure of carbody and evaluate safety under maximum vertical load, compressive load, and torsional load. Accordingly, stress tests were conducted on the carbody to measure the stress on each of their parts. Before the load test, a structural-analysis program was used for the stress distribution analysis of the body structure.

• Journal of the Korean Society of Manufacturing Technology Engineers
• /
• v.24 no.2
• /
• pp.177-185
• /
• 2015

This paper describes a weight-reduction design method for the car bodies of a double deck high-speed train (service speed of 300 km/h). The method uses lightweight materials and a topology optimization technique. In this study, aluminum extrusions and sandwich composites were selected as the best materials to reduce the weight of the car body. The topology optimization technique was used to determine which car body parts could be made of the sandwich composites to achieve additional weight savings. The results of the topology optimization analysis showed that sandwich composites could be used for secondary car body members such as the roof and the second underframe. Also, it was found that a car body composed of aluminum extruded parts and sandwich composites could weigh up to 14% less than a car body made of only aluminum extrusions.

• Journal of the Korean Society for Railway
• /
• v.12 no.4
• /
• pp.557-564
• /
• 2009

This study compared KORAIL's procurement tasks with that of other companies. after analyzing the institutional and operational problems in procurement tasks especially in the respect of rolling stock and components which are KORAIL's major purchasing items, this study presented the way of purchasing cost Reduction through improving and streamlining procurement tasks.

• Journal of Korean Society for Atmospheric Environment
• /
• v.25 no.3
• /
• pp.237-247
• /
• 2009

The combustion characteristics of car components have been investigated, The combustion parameters like heat release rate, smoke production, yield of carbon dioxide and carbon monoxide and mass loss rate were analyzed by cone-calorimeter for representative samples (seat, carpet, headrest, rubber mat, dash board and electric wire) collected from a used car. The results from sample combustion showed that cover and sponge in seat more quickly ignited and flamed than other parts. The heat released from the combustion of dash board sample was 144.29$kw/m^2$ and the smoke produced by the wire combustion was 6896.4 $m^2/m^2$. The yields of carbon dioxide and carbon monoxide were in the ranges of 1.09${\sim}$2.76 kg/kg and 0.0262${\sim}$0.1008 kg/kg, respectively.

• Journal of the Korean Society for Railway
• /
• v.20 no.3
• /
• pp.339-348
• /
• 2017

Power supply for railway cars can be divided into propulsion system power supply and auxiliary power units (APU). The propulsion system power supply is for propulsion of railway cars, and regenerative braking; the APU provides power for the air compressor, lighting, car control and other auxiliary parts. According to high voltage and high current specifications, generally, an insulated-gate bipolar transistor (IGBT) is adopted for the switching component. For appropriate switching operation, a gate driver unit (GDU) is essentially required. In this paper, the technical trends of GDU for railway cars are analyzed and a design consideration for IGBT GDU is described.

• Transactions of the Korean Society of Mechanical Engineers A
• /
• v.35 no.2
• /
• pp.213-221
• /
• 2011

In this study, we discussed the weight reducing of a urban railway-car body, in particular, of the Korean EMU, by optimizing topology and size of aluminum extrusion profiles. The heaviest parts of aluminum railway-car bodies, i.e., the base plate of underframe and side panels of side frame composed of double skin structures are considered for optimization. Topology optimization process is applied to obtain get an optimized rib structure for the base plate. The thickness of ribs and plates of the topologically optimized base plate and the existing side panel are also optimized by employing the size optimization process. The results are verified by comparing the maximum von Mises stresses and maximum deformation in the case of the existing design with those in the case of the optimized design. It is shown that the weight of a base plate and side panel can be reduced by 12% and that the weight of the whole car body can be reduced by 8.5%.

• Proceedings of the KSR Conference
• /
• 2010.06a
• /
• pp.540-545
• /
• 2010

As the urban railroad durability period law has revised on march 19, 2009, the life cycle of urban railroad cars has lengthened to 40 years for the longest period. It seems to be attributed to the development of railroad car making technique along with their durability being longer thanks to the quality improvement of their materials and parts. As the stability of urban railroad cars is directly linked to the safety of passengers, safety should be considered first, and more precise examination is necessary for endurance extension. Hereupon, the rolling stocks with their durability near expiration should get precise diagnosis following the revised "RDG for urban railroad cars" This study aims to suggest a diagnosis method for the institute and the urban railroad operating body which enforce the revised diagnosis, through the case of Busan transportation corporation which firstly started the revised diagnosis after the durability related law has been revised.

• Journal of the Korea Academia-Industrial cooperation Society
• /
• v.19 no.1
• /
• pp.75-84
• /
• 2018

Increasing the operation rate of components and stabilizing the operation through timely management of the core parts are crucial for improving the efficiency of the railroad maintenance industry. The demand for diagnosis technology to assess the condition of rolling stock components, which employs history management and automated big data analysis, has increased to satisfy both aspects of increasing reliability and reducing the maintenance cost of the core components to cope with the trend of rapid maintenance. This study developed a big data platform-based system to manage the rolling stock component condition to acquire, process, and analyze the big data generated at onboard and wayside devices of railroad cars in real time. The system can monitor the conditions of the railroad car component and system resources in real time. The study also proposed a machine learning technique that enabled the distributed and parallel processing of the acquired big data and automatic component fault diagnosis. The test, which used the virtual instance generation system of the Amazon Web Service, proved that the algorithm applying the distributed and parallel technology decreased the runtime and confirmed the fault diagnosis model utilizing the random forest machine learning for predicting the condition of the bearing and wheel parts with 83% accuracy.

• KSCE Journal of Civil and Environmental Engineering Research
• /
• v.38 no.6
• /
• pp.1001-1012
• /
• 2018

Regarding the small- and medium-sized enterprises in Korea that manufacture the railway vehicle parts, there are over 250 related companies. And they have been surviving in the form of producing and delivering the parts of the railway vehicles by importing the technologies and the products of the foreign countries rather than possessing their own technological abilities. Due to this, regarding the industry of the core components of the railroads, the dependence on the overseas has been high. As such, although, for supporting the small- and medium-sized enterprises that manufacture the railway vehicle parts, the government has been strengthening the diverse policy supports, it is a fact that the effectiveness of the support is not high. And, in order to effectively support these, there is a need to understand clearly and definitely what the important promotion factors are in the process of the technology commercialization. Accordingly, through the precedent researches regarding the factors that promote the technology commercializations of the small- and medium-sized enterprises that manufacture the railway vehicle parts, this research had extracted 10 main items. And the level of the importance of these indices was analyzed by using the AHP (Analytic Hierarchy Process). As a result of the AHP analysis, the factors within a corporation appeared to be the most important factor. And, as for the lower-ranking item, the commercialization capability was analyzed to be the most important item. It is highly expected that the contents and the results of this research will be usefully used when formulating the planning of the support program and the support policy for the technology commercializations by the public research organizations and the railroad management organization, which is an organization that supports the small- and medium-sized enterprises that manufacture the railway vehicle parts.

• The Journal of the Korea Contents Association
• /
• v.17 no.1
• /
• pp.50-57
• /
• 2017

This study investigated the causes and problems of train operation impediments through the statistics analysis of 8 years'internal data of Daejeon Metropolitan Express Transit. By evaluating the risks regarding the system, equipment, and parts of high risk group, this study measured the Risk Index Severity, and applied the $5{\times}5$ Risk Assessment Matrix which is a method of risk management to calculate the scale of risk to analyze the safety level and allowance range. As a result, the car sector, the most serious risk, followed by machinery and equipment sector showed that the inherent risk. In particular, the door broken and the door rail signaling and control devices due to defects of the vehicle is high, but also the severity, and frequency are showing very frequent additional potential accidents. PSD also had defects in the machinery sector appeared to be the most dangerous of the PSD poor safety gates, it was found that the glass also involve the risk of mishandling and breakage of the PSD. This study intended to contribute to the transportation benefits through the safety and stable operation of Metropolitan Express Transit.