• Journal of The Korean Society For Urban Railway
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• v.6 no.4
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• pp.411-416
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• 2018

It is generally not preferable to install a turnout on a sharp curves but it is not desirable for the safety of a train. However, in a mountainous area or a depot where a sufficient space can not be secured to secure a straight line. In this study, in order to analyze the cause of train derailment accident that occurred in the place where turnout is installed in a sharp curves, we performed derailment analysis using line data and accident vehicle data measured at the location where the accident occurred. This derailment coefficient maximum turnout at the start of the track and derailment curve analysis showed that even big enough to cause a derailment as 1.37 in size, which was found to be consistent with the actual site survey results derailment occurred.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.37 no.6
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• pp.827-832
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• 2013

In this study, curve responsiveness was assessed based on the lateral force and running safety was evaluated based on the wheel unloading ratio and derailment coefficient, which is the ratio of the wheel load and the lateral force. The evaluation of the curving performance and running safety of the new high-power electric locomotive showed that the derailment coefficient appeared higher when the wheel-set was set to the front of the train instead of being placed backward, and the maximum value of the derailment coefficient was recorded as 0.572 on the Gyeongbu line. Furthermore, the lateral force increased in curved sections, and it appeared to be proportional to the curve radius. Meanwhile, a maximum axis lateral force of 77.6 kN was recorded on the Taebaek line, and the wheel unloading ratio was 47.6% on the Yeongdong line. Finally, the running safety at the maximum speed as well as the through-curve performance of the curve radius satisfied the required standards.

• Proceedings of the KSR Conference
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• 2011.10a
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• pp.1914-1921
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• 2011

When a railway vehicle passes through curves & transitions, the running speed must be improved by proposing the standards on the maximum running possibility speed of each section on conventional line (Dongdaegoo-Namsunghyun) considering derailment safety. In this paper, To improve the maximum running possibility speed of railway vehicle which passes through curves which have high risk of derailment, the track alignment conditions of conventional line (Dongdaegoo-Namsunghyun) that present transition curve length in current railway construction regulations are controlled. We presented elevation way about the section maximum running possibility speed in conventional line by analysis result.

• Journal of the Korean Society for Railway
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• v.7 no.4
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• pp.367-373
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• 2004

The investigation of running stability of the train for curved track is necessary in view of preventing the train from derailment caused by unbalanced forces transferred from the wheel and guaranteeing moderate level of running safety in curve sections. This paper carried out an analysis of running stability of tilting trains in conventional line which the test operation of tilting trains under development are scheduled. For this purpose, the wheel load and lateral pressure to the rail are evaluated. The criteria for the calculated wheel load and derailment coefficient are compared to the design criteria for running stability. It is founded that the running stability of tilting trains for curved track is guaranteed to have sufficient safety and the train speed in curve is governed by the geometric layout of track rather than the criteria for running stability.

• Proceedings of the KSR Conference
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• 2011.10a
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• pp.1905-1913
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• 2011

The dynamic characteristic of bogie that is driving system of railway vehicle is very important regarding decision of vehicle characteristics as running safety and comport. The dynamic characteristic test of bogie is tested on full size in place on field testing on track. But, the testing on the full size caused many problems. To overcome these problem by full size test, the Railway Safety Research Center in Seoul National University of Science & Technology developed 1/5 scale size of small scale derailment simulator and is currently testing running stability of 1/5 scaled bogie. Also To take effectively advantage of running stability test using small scale derailment simulator in actuality design and reliability estimation, it is necessary comparison and examination with field test and theoretical analysis result In this paper. to achieve running stability analysis of 1/5 scaled bogie on small scale derailment. the program using MATLAB that is fast compose and analysis the motion equation of Saemaul power bogie is developed. It is achieved analysis according to various specification (weight, size, suspension, etc..) and is evaluated corelation between test result and dynamic characteristic of actual railway vehicle.

• International Journal of Railway
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• v.4 no.2
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• pp.50-55
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• 2011

The dynamic stability of railway vehicle has long been one of the important issues in railway safety. The dynamic simulator has been used as a tool for investigating the dynamic stability of railway vehicles and wheel/rail interfaces. In particular, small scale simulators have been widely used in laboratory studies instead of full scale roller rigs which can be quite costly and rather inconvenient for testing out the effect of diverse design parameters. But techniques for design of a small scale simulator for the fundamental study about the dynamic characteristics of the wheel-rail systems and the bogie systems have not been well developed in Korea. Therefore, a research on the development of a small scale simulator for investigating bogie dynamics needs to be undertaken. The present paper investigates design of a small-scaled derailment simulator and the design of a small scale bogie. The simulator developed can be used to investigate the effect of diverse parameters such as attack angle, wheelbase and cant on dynamic behavior of the bogie and key dynamic performance parameters such as derailment coefficient and critical speed.

• Transactions of the Korean Society for Noise and Vibration Engineering
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• v.23 no.3
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• pp.199-208
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• 2013

So far today, there is a speed limit by the radius of curve based on operation regulation in domestic railway, however a study for the maximum running speed at the curved section without any derailment would be necessary. The two major factors related to the running safety of railway vehicle are classified as the railway vehicle condition and the track condition. In terms of the rail inclination among many other factors, the determination of rail inclination within the possible limit is necessary for the geometrical structure of the optimum track. The disregard of the geometrical parameter related to the rail inclination may cause a serious problem to the running safety of railway vehicle. This study is focusing on the analyzing of running safety regard to the change of rail inclination among the many other parameters to improve derailment safety, so that there is an affection analysis of the running safety regard to the change of rail inclination in the ideal and geometric track condition. Also There is an affection analysis of the running safety regard to the simultaneous change of rail inclination and the running speed at the curved section. According to analysis results of running safety, In case that the left and right rail inclination are 1/40, the running safety of this condition defined than other conditions. Also, the rail inclination of conventional lines is 1/40, Therefore, the railway vehicle passing through curve is safe when the railway vehicle runs in conventional lines.

• Journal of the Korean Society of Safety
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• v.33 no.2
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• pp.145-151
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• 2018

In this study, the track-bridge interaction analysis was performed using an analytical model considering the track structure, thereby taking into account the linear conditions (R=650 m, cant variation $160{\pm}60mm$) and the dynamic characteristics of the bridge. As a result of the study, the allowable speed on the example bridge considered was calculated at 200 km/h based on vertical deflection, vertical acceleration, and irregularity in longitudinal level, but was also evaluated at 170km/h based on the coefficient of derailment, wheel load reduction, and lateral displacement of the rail head. It is considered desirable to set the speed 170km/h to the speed limit in order to secure the safety of both the bridge and the track. It is judged that there will be no problems with ensuring rail protection and train stability in the speed band.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2005.10a
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• pp.12-15
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• 2005

In April 1, 2004, age of high-speed railway was opened to korea railroad. The railroad is a means of large transportation which has many talents 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 farce, 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, examined speed elevation possibility use the korean style high speed railway vehicle for reduce the running time of high-speed railway between high speed line and conventional line.

• Proceedings of the KSR Conference
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• 2007.11a
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• pp.1858-1863
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• 2007

Railway systems are one of the best mass transit systems and many people have prevented incidents/accidents and reduced fatalities remarkably. Especially we have tried analyzing and finding the measures to prevent catastrophic accidents like train collision, derailment and fire because of their severities. It is important to assess the safety performances of railway systems like crash-worthiness analysis, body, derailment affecting factor analysis and so on for reducing and finding out the reasonable causes of disastrous accidents. In this paper the refined top-level system requirements to build-up national infra for assessing railway safety performance and the procedures and methodology for reviewing, verifying and validating infra requirements are explained. Basically the authors have used system engineering processes to analyze and verify the requirements and installation procedures and have tried maximizing the practicality of the various safety assessment systems.