• Journal of Environmental Science International
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• v.19 no.7
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• pp.917-929
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• 2010

This paper aims to find out the statistical characteristics of the weather related railroad accidents and incidents. Data from Korea Railroad Operation Information System(KROIS) and Korea Railroad Accidents reports during 1996-2008 were used to investigate the occurrence frequency of railroad accidents and operation obstacles and their association with weather phenomena. The results are as follows; The occurrence frequency of railroad accidents and operation obstacles decrease gradually, and most of railroad accidents is a railroad traffic accidents. The amount of damages by a railroad weather-related accidents is higher than those of the railroad accidents and operation obstacles. It was also found that weather events influencing the railroad weather-related accidents and incidents are rainfall, snowfall, lightning, winds. And they caused a railroad weather-related accidents and incidents, such as railway obstruction, signal failure, and power supply failure. Therefore we need research about threshold review and a quantitative and qualitative analysis of a railroad weather-related accidents and incidents according to climate change.

• Journal of the Korean Society for Railway
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• v.11 no.5
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• pp.477-481
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• 2008

This paper dealt with a detection method of series arc existence which is a symptom of electric fires in low-voltage system. The proposed detection circuit consists of a high-pass filter with a low cut-off frequency of 3kHz to attenuate power frequency voltage by 80 dB and an active band-pass filter with a center frequency of 4kHz to detect only the series arc signals. The performance of the circuit was evaluated in a phase-controlled incandescent lamp as a non-linear load and an inverted-fed induction motor as a high frequency load by using the arc generator specified in UL1699. From the experimental results, it was confirmed that the proposed method solved the detection error, which is being the most problem, by discriminating the series arc signal even in non-linear and high frequency loads.

• Proceedings of the Korean Geotechical Society Conference
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• 2010.03a
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• pp.208-212
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• 2010

The high-speed railway consists of tracks, gravel ballast and subgrade, and the dynamic load is passed to subgrade through track and gravel ballast. The relaxation condition of the gravel ballast is able to be evaluate relatively and to be repaired through a continuous management, but it is difficult to evaluate the condition of subgrade, which is final part of supporting dynamic load and to repair it when made a problem. The gravel ballast and subgrade are evaluated by determining shear wave velocity. To evaluate ballast and subgrade, a good method to determine shear wave velocity is a non-destructive experiment such as surface wave tests providing a prompt experiment because an experiment in railway has a lot of tests which are carried out following railway directions and needs to prevent damage of the system. In general, a railway has limitation of an experimental space by narrow width, sleeper and etc., and background noise by a reflector exists. The existing surface wave tests need a minimum space, and it is difficult to get a reliable test results on account of background noise effect. Therefore, it is difficult or impossible to apply to existing surface wave test of subgrade and ballast. In this study, the HWAW method is applied to determine a shear wave velocity profile of the underground. The HWAW method is the experiment which is able to be carried out on a narrow space, and it determines share wave velocity of a site by measuring the wave from surface sources on the same spot. In addition, it removes effects of background noise accordingly to a signal processing using harmonic wavelet transforms, so it is useful to evaluate subgrade of a high-speed railway in the narrow space and the situation of background noise. In order to check an application of the HWAW method, an experiment is carried out on a high-speed railway field and a test result is compared to boring results.

• The Transactions of the Korean Institute of Electrical Engineers P
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• v.59 no.2
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• pp.206-211
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• 2010

Since high-speed train is a dynamic load in which electric power is externally supplied, contact loss between the catenary and pantograph occurs. This phenomena including vibrations generates frequently irregular arcs, which, in turn causes EMI. Thus it is very important to develop the approach to reduce arc phenomenon by contact loss, as speed of electric railway vehicle increases. In case of an electric railway vehicle using electrical power, compared with diesel rolling stock, Power Line Disturbance(PLD) such as harmonics, transient voltage and current, Electromagnetic Interference(EMI), and dummy signal injection etc usually occur. In this study, the dynamic characteristics of a contact wire and a pantograph suppling electrical power to high-speed train are investigated with an electrical response point. To implement power line disturbance induced by contact loss phenomenon for high speed train operation, a hardware simulator which considers contact loss between contact wire and pantograph as well as contact wire deviation is developed. It is confirmed by the experiments that contact loss effect is largely dependent on voltage conditions when the contact loss occurs. Also, a passive filter is designed to reduce power disturbance and the designed system is verified by experiment.

• Proceedings of the KSR Conference
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• 2008.06a
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• pp.332-338
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• 2008

This paper handles, implementation of multiple access bidirectional serial communications protocol using two common DC power lines, whict are power supply and ground, connecting multiple devices. Communication between the host and the multiple clients are performed using unique packet data with device ID unique to each devices connected on the common power lines. Host initiates data communications by transmitting command packet to the designated client with the client's ID and the client responds by transmitting response packet to the host and in this way, multiple clients and host exchange the packet through the common power lines. The normal voltage of the power communication line maintains 24V corresponding to level 1 and the host drops the voltage to 12V on sending level 0 signal, also the clients normally keeps the line voltage to 24V use pull-down circuit to drop the voltage to 12V on sending level 1 signal. Power supply originates from the host, the host senses the voltage level of the power communication lines and when the clients activates pull down circuit to send level 0 signal and the voltage drops to 12V, the hosts switches power source from 24V to 12V. Also, when clients deactivate pull down circuit to send level 1 signal, the host senses the voltage increase and switches the power source from 12V to 24V. Experimental circuit is designed with one hosts and four clients and verified the power line voltage switching operation depending on the data signal levels on the power line. The proposed research result can be applied to two wire power communications system with one host and multiple low current consumption clients.

• Proceedings of the KIEE Conference
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• 2002.07b
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• pp.1292-1294
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• 2002

In this study, the block section length of the given area has been analyzed to improve the headway which caused by the mixed operation of high speed trains and normal trains on the electrified railway of Dongdaegu to Busan. After establishing the average length of block section and the adjustable average length of block section of Dongdaegu to Busan, it is possible to perform the headway simulation regarding the signal system based on the established length. Although high speed trains as well as low speed trains including freight trains operate together, the experimental results indicate that the modification of the block section length shows the possibility of the improvement of headway.

• Proceedings of the KSR Conference
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• 2011.05a
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• pp.666-670
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• 2011

ATS(Automatic Train Stop)s are is effected by track environment, signal distance and train braking distance. So onboard signaling systems such as ATP(Automatic Train Protection) are installed on conventional lines by some train operation companies. With the mixed signalling, the onboard signaling system is overlaid on a conventional line with ATS, it is possible to run the line with conventional trains and ATP trains and to use the advantages of ATP(higher speed or more trains on the line). This paper includes guidelines a mixed signalling(ETCS and ATS) system architecture, operation concepts and infill balise installation.

• Proceedings of the KSR Conference
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• 2011.10a
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• pp.2286-2291
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• 2011

Technology on the rolling stock is very composition and system engineering. We have to consider to many parameters on the rolling stock design. High speed train is interface between rolling stock and infra system of rail, signal, communication etc. For many years testing operation has experienced substantial growth based on various advanced new technology. Recently some problems was clearly stated on effective management, practical use and testing operation of the the rolling stock on the technology change. This paper presents some results of the study on necessary requirements of the operation testing for rolling stock technology change. We propose a general plan to suggest the operation testing and the parameters of the rolling stock on the technology change in the text.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2003.06a
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• pp.507-512
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• 2003

The railroad is a means of large transportation which has many latents such as a safety and a regularity. That is a results from various confidential performance tests and evaluations of the system. The railroad system consist of various subsystems - vehicle, power supply, signal, communications, track structures, operations, etc. Among them, as an item of safety evaluation there is a measurement of wheel/rail force, so called a measurement of derailment coefficient. This is a very important item because a derailment of a train will bring about a big accident. Especially it is more important in high speed rail of which operation speed is over two times as fast as existing rail. In this paper, it is introduced to preprocess the wheelset for measuring wheel/rail force of high speed rail, such as to treat a measuring wheelset, its finite element analysis, adhesion of strain gauges and static toad test, running test result of main line.

• Proceedings of the KSR Conference
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• 2007.11a
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• pp.612-617
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• 2007

Several cases of foreign to basis much researches for old line speed elevation of internal railroad consist. Examine about improvement and development of consisting signal system in internal. Examine about establishment of suitable examination and formality creation for road test and road test plan in domestic environment. Effective application of skill development work and examination for technique security and road test planning should be established. Studied about examination of internal old line speed elevation business and road test direction that progress current.