• Journal of the Korean Society for Precision Engineering
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• v.28 no.5
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• pp.559-564
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• 2011

For the safety of railway, it should be evaluated for the running safety by measuring the derailment coefficient. Although railway has run the fixed and maintained rail, some of railway is derailed. This report shows the results that performed the static load test, main line running test on the basis of the derailment theory and experience. It is executed main line test into more than 90km/h for estimating the curving performance and running safety of depressed center flat car of 3-axle bogie. As the test results, could confirm the curving performance and running safety of depressed center fiat car of 3-axle bogie from the results of the wheel unloading, lateral force, derailment coefficient etc. Derailment coefficient was less than 0.6, and lateral force allowance limit and wheel load reduction ratio were enough safe.

• International Journal of Railway
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• v.5 no.2
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• pp.93-101
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• 2012

Owing to the lightening of railway vehicles and increased operation speeds, the reduction of running safety in the presence of crosswind is becoming an important problem. In particular, the running safety tends to decrease when vehicles run on curved track. When a crosswind acts on a vehicle negotiating a curve from the outer side, flange climbing can occur. In this study, a full-vehicle model was constructed using the multi-body simulation software SIMPACK, and a simulation of a bogie vehicle with two-axle trucks negotiating a curve was carried out to examine the running safety under the condition where a crosswind acts on the vehicle from the outer side of the curve. As a result, it was verified that the derailment coefficient of the first wheelset becomes large in the exit transition curve and the coefficient of the third wheelset does in the entrance transition curve, and this trend becomes pronounced at low operation speeds in the presence of a stronger crosswind. It was also shown that the critical derailment coefficients obtained by modified Nadal's formula considering the effect of attack angle become close to the actual derailment coefficients at the timing that flange climbing occurs.

• International Journal of Railway
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• v.3 no.2
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• pp.60-67
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• 2010

This paper deals with an experimental study on the wheel flange climbing of railway vehicles, which is a major factor leading to derailment. An experiment is carried out on a 1/5-scale model wheelset of a truck used on a standard-gauge track, which is placed on a roller rig. The lateral external force acting on the wheelset is ramped up until derailment occurs under the condition of a fixed attack angle and wheel-load unbalance ratio. Three parameters, the height of wheel lift, the lateral force, and the wheel load acting on the outer rail, are measured until derailment occurs. From these measurements, it is possible to observe the behavior of the wheelset and to elucidate how the attack angle, the wheel-load unbalance ratio and the lateral external force affect flange-climb derailment. Then, a numerical simulation is carried out using an analytical model based on a single wheelset. As a result, the flange-climb behavior observed in the experiment can be explained theoretically on the bases of the analytical results, although further improvement of the model is desired.

• Proceedings of the KSR Conference
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• 2011.05a
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• pp.1128-1133
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• 2011

This is a testing equipment system to analyze variation of creep force according to wheel-rail tread profile, running speed of vehicle, vertical and lateral force, wheel/rail contact point, attack angle and so on. The creep force affect vehicle derailment, especially climbing derailment. This system is composed of main frame, wheelset and rail disks driver, hydraulic actuator, controller, environmental chamber, safety system and so on.

• Proceedings of the KSR Conference
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• 2011.10a
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• pp.62-68
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• 2011

This is a testing equipment system to analyze variation of creep force according to wheel-rail tread profile, running speed of vehicle, vertical and lateral force, wheel/rail contact point, attack angle and so on. In this paper, derailment occur in stages until the change of each parameter, while reproducing the actual situation was derailed. Thus, to derail what is the most influencing factors were analyzed.

• Journal of the Korean Society for Railway
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• v.2 no.2
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• pp.6-12
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• 1999

In this study, the most important suspension characteristics of railway vehicle, such as primary and secondary stiffness, are optimized to maximize ride qualify. Critical speed, secondary suspension stroke oil tangent track and derailment coefficient on the maximum curvature, are selected as the performance constraints. Piecewise linear curving model is used to evaluate derailment coefficient where it is assumed that wheel/rail contacts occurs at tread or at idealized flange. The combined design procedure is used to optimize above design variables at the same time.

• Proceedings of the KSR Conference
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• 2007.05a
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• pp.1174-1179
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• 2007

Train collision and derailment are types of accident that happen with low probability of occurrence but could lead to disastrous consequences including multiple life losses. Risk assessment of the accidents are typically performed per their hazardous events, which are defined as events that cause accidents. This study classifies the train collision and derailment based on the relevant hazardous event, and investigates the causes related to the hazardous events. Finally, the relation of the causes, hazardous events, and the accidents are defined.

• Proceedings of the KSME Conference
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• 2008.11a
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• pp.481-484
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• 2008

The important factor to evaluate the running safety of a railway vehicle would be the interaction force between wheel and rail(derailment coefficient), for which is one of important factors to check the running safety of a railway vehicle that may cause a tragic accident. Element that analyze derailment coefficient is consisted of wheel load and lateral force. In this paper, studied about method that calculate vertical force(wheel load) by bending load of axle in rolling stocks.

• Transactions of the Korean Society for Noise and Vibration Engineering
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• v.22 no.3
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• pp.244-252
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• 2012

Recently, the speed of a train has been increased. So the trains are being exposed to wind more severely than before. Because of the operation of high speed trains and lightweight of the train, risks of train derailment have being increased. In this study, aerodynamic effects of a newly designed high speed train, HEMU-400x, are evaluated. For aerodynamic effect evaluation, analysis method is selected by examining the safety standards for high speed train. The condition of aerodynamic effects is selected by adverse effect conditions. In order to calculate $C_s$ coefficients, numerical analysis is conducted. Using $C_s$ coefficients, the side force is calculated. Through dynamics analysis, derailment and wheel unloading are obtained. Using these results, derailment evaluation is performed.

• Proceedings of the KSR Conference
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• 2004.06a
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• pp.608-612
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• 2004

Safety from derailment has been evaluated according to the magnitude of the derailment coefficient, which does not always ensure sufficient safety evaluation, and is not necessarily helpful in clarifying the mechanism of derailment. When wheel rolls, point of contact between wheel and rail was change continuously and flange touches with rail. Established gauge so that can measure location of contact point between wheel and rail by strain gauge. Also, wish to describe result that compose bridge circuit and execute load test.