• International Journal of Railway
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• v.2 no.1
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• pp.8-17
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• 2009

The wheelset, its functions and position under the train is the prime safety-critical component. Whether in design, qualification, manufacturing or maintenance, the wheels and axles have been the focus of special attention at SNCF for over 25 years and the French Railways are actively involved in various Research and Development work towards interoperability between the railways, railway reliability and running safety.

• Journal of the Korean Society for Railway
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• v.9 no.2 s.33
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• pp.145-150
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• 2006

In this study, overturning safety for a tilting train has been evaluated. In the tilting train, the overturning safety is one of the most important factors because the carbody inclines inward a curve during curve negotiation. Dynamic analysis considering unbalanced lateral acceleration and carbody tilting has been carried out and the overturning safety for the tilting train has been evaluated according to height of CG of carbody. From these studies, the overturning safety for the tilting train under unbalanced lateral acceleration of $2m/s^2$ was superior to the conventional one at the same running speed.

• Journal of the Korean Society of Surveying, Geodesy, Photogrammetry and Cartography
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• v.14 no.2
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• pp.229-239
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• 1996

for shortening of running time on existing line, speed up railways feel strongly the necessity of it, for fully realizing a role of transportation system, for human life style is high. and increasing of time value. Especially curved lines zone have crucial effects on the speed of train, in case the shortening of running time, it is thought, speed up in curved lines zone, considering a character of route alignment in korea, we obtain saving time using lateral force index for safety running of train and comfortable ride of passengers. The results of this study show that all curved zone improvements for the shortening of the train running time more efficiently than extension of transition curve.

• Proceedings of the KSR Conference
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• 2010.06a
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• pp.50-57
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• 2010

Various installation faults may lie in fasteners in the construction of a direct-fixation track by the top-down method. At an extreme, they may cause excessive interaction between the train and track, compromise the running safety of the train, and cause damage to the track components. Therefore, the faults need to be kept within the allowable level through an investigation of their effects on the interactions between the train and track. In this study, the vertical dynamic stiffness of fasteners in installation faults was measured based on the dynamic stiffness test by means of an experimental apparatus that was devised to feasibly reproduce gap faults. This study proposes an effective analytical model for a train-track interaction system in which most elements, except the nonlinear wheel-rail contact and some components that behave bi-linearly, exhibit linear behavior. To investigate the effect of the behavior of fasteners in gap faults in a direct-fixation track on the vehicle and track, vehicle-track interaction analyses were carried out, targeting key review parameters such as the wheel load reduction factor, vertical rail displacement, rail bending stress, and mean stress of the elastomer. From the results, it was noted that the gap faults in the concrete bearing surface of a direct-fixation track need to be limited for the sake of the long-term durability of the elastomer than for the running safety of the train or the structural safety of the track.

• Journal of the Korean Society for Railway
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• v.14 no.5
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• pp.433-441
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• 2011

It is a fact that the straightening of track alignment is one of the undoubted ways to improve the train speed on conventional lines, while that requires huge investment resources. Therefore, the operation of a tilting train as well as the minimum improvement of track is suggested as an effective and economical alternative way for the speed-up of conventional lines. Since a driving mechanism of tilting train is different from those of existing trains, in order to make sure its operation safety and stability on conventional line, the performance of track and roadbed must be preferentially evaluated on the conventional line. Furthermore, it is necessary to estimate the tilting-train-induced roadbed response in detail since the roadbed settlement can lead to the track deformation and even derailment. In this research, the patterns of wheel load and lateral force were monitored and analyzed through the field tests, and the derailment coefficient and degree of wheel off-loading were calculated in order to evaluate the tilting train running safety depending on the running speeds (120km~180km) on the conventional line. Moreover, roadbed pressure, settlement and acceleration were also observed as tilting-train-induced roadbed responses in order to estimate the roadbed stability depending on the running speeds. Consequently, the measured derailment coefficient and degree of wheel off-loading were satisfied with their own required limits, and all of the roadbed responses were less than those of existing high-speed train (KTX) over an entire running speed range considered in this study. As a result of this study, the tilting train which will be operated in combination with existing trains is expected to give no adverse impact on the conventional line even with its improved running speed.

• Proceedings of the KSR Conference
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• 2010.06a
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• pp.1937-1942
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• 2010

Vehicle dynamic behavior should be investigated to establish the track irregularity criteria because they have an impact on vehicle dynamic behavior. The tilting train which have been developed in Korea will be operated on the conventional line. Therefore, it should be checked that the track irregularity criteria of conventional line is still available for the new vehicle. In this paper, the influence of vertical alignment on running behavior and safety for tilting train was instigated by numerical analysis. The wavelength and amplitude of vertical alignment were considered in scenario of this numerical analysis. This research is based on just numerical analysis and the final result which include measurement will be published in the future.

• Proceedings of the KSR Conference
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• 2008.06a
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• pp.2156-2162
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• 2008

To reduce the cost and the time of transport in Eurasian railroad networks such as TKR, TCR and TSR owing to the problem of different track gauges (narrow/standard/broad gauge), it is important to develop the gauge - adjustable wheelset system to adapt easily to these gauges. The gauge - adjustable wheelset system in the transcontinental railway have been proposed as a more effective way in comparison with other techniques for overcoming difference in track gauges. Assume that the freight train with gauge adjustable wheelset system is running from domestic train network to TCR, TSR in Eurasian continent, it is necessary to estimate the safety of this system. This study is evaluated at examination of safety for freight train with gauge adjustable wheelset system by simulated durability analysis. Moreover, the predicted fatigue life at running track using the durability simulator was verified by the durability test according to UIC standard.

• Wind and Structures
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• v.32 no.5
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• pp.487-499
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• 2021

The wind-blown sand effect on the high-speed train is investigated. Unsteady RANS equation and the SST k-ω turbulent model coupled with the discrete phase model (DPM) are utilized to simulate the two-phase of air-sand. Sand impact force is calculated based on the Hertzian impact theory. The different cases, including various wind velocity, train speed, sand particle diameter, were simulated. The train's flow field characteristics and the sand impact force were analyzed. The results show that the sand environment makes the pressure increase under different wind velocity and train speed situations. Sand impact force increases with the increasing train speed and sand particle diameter under the same particle mass flow rate. The train aerodynamic force connected with sand impact force when the train running in the wind-sand environment were compared with the aerodynamic force when the train running in the pure wind environment. The results show that the head car longitudinal force increase with wind speed increasing. When the crosswind speed is larger than 35m/s, the effect of the wind- sand environment on the train increases obviously. The longitudinal force of head car increases 23% and lateral force of tail increases 12% comparing to the pure wind environment. The sand concentration in air is the most important factor which influences the sand impact force on the train.

• Proceedings of the KSR Conference
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• 2010.06a
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• pp.1703-1712
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• 2010

The safety of tilting train running on curved track is, in general, evaluated with a derailment coefficient calculated by the ratio of wheel load and lateral force, Particularly on curve, the wheel load and lateral force on rail may cause trackbed to be deformed, depending on their intensity, and moreover, often result in critical accident such as derailment. This study hence was intended to identify the cause of wheel load and lateral force so as to suggest the allowable wheel load reduction rate, lateral force limit and derailment coefficient, thereby quantitatively evaluating the operational safety of tilting train. This study therefore was aimed to analyze the wheel load and lateral force occurred during tilting train's operation on circular curve in such a way of comparing with traditional trains, by axle and speed, in a bid to eventually evaluate the operational safety of tilting train.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 1997.10a
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• pp.210-215
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• 1997

Safety diagnosis on the driving system of electric train is performed using the vibration and noise signals of running railway train. Safety diagnosis is tried on the viewpoints of the appreciation of superannuation and the fault diagnosis of motor, reduction gear and boggie. The appreciation of superannuation is checked by the rms vibration levels of driving parts and the fault diagnosis is done by analyzing the frequencies of the vibration signals. The methods of measuring and analyzing the signals are decided on the basis of field 1-measured signals. The results shows that the vibration levels of each parts increase as the train goes older and each parts have their own frequency patterns of the vibration. As the results, the vibration and noise can be utilized successfully for the safety diagnosis of the driving part of electric train.