• Proceedings of the KSR Conference
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• 2010.06a
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• pp.58-63
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• 2010

HEMU-400X train have been developed and will be operated over 350km/h. In this paper, the influence of vertical alignment on running behavior and safety for HEMU-400X 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 Korean Society for Noise and Vibration Engineering Conference
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• 2007.05a
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• pp.297-303
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• 2007

Derailment is likely to have a direct connection with human life and must be eliminated. A traveling safety evaluation method based mainly on derailment coefficient has already established. But this method is very difficult because Derailment is caused by multiple factors. To evaluate the derailment factor of running train that runs on the curved track, we make use of mechanism that wheel loads and lateral forces were affected by track and rolling stock parameter. In this paper, deal with a search on the parameter and derailment factor. According to results of computer simulation value of Q/P, running safety is connected with operation velocity, curve radius, cant, track irregularity, suspension stiffness and static wheel load ratio, SMRT train Line No. 5 Bogie is selected to do numerical study considering rolling stock and track condition.

• Proceedings of the KSR Conference
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• 2011.10a
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• pp.2891-2894
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• 2011

Recently, the rise of the rail temperature is accelerating further due to the global warming, and the track stability(buckling) problem result from the axial force in the continuous welded rail(CWR) have become the most important issue. This track stability threatens the security of running trains in the hot summer. In order to prevent the track buckling in the hot summer and ensure the safety of the running train, as a part of the safety control plan for KORAIL high-speed railway, the train speed restriction according to the rail temperature was introduced in 2004. However, the conceptual and theoretical background of train-speed restriction is uncertain. In this paper, the theoretical study about the reasonable train-speed restriction is performed. For this purpose, the risk-based probabilistic stability evaluation of the track buckling is applied.

• International Journal of Railway
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• v.3 no.2
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• pp.68-72
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• 2010

Railway vehicles equipped with semi-active suspension system can improve the ride quality of car bodies. Semi-active suspension system is usually applied onto high speed train, and therefore higher running safety requirement is desirable. The influence of semi-active suspension system on safety of vehicles running on straight line and curve line is studied, and the influences of sky hook damping coefficient and system time-delay on operational safety of cars fitted with semiactive suspension system is analyzed. The results show that in vehicles equipped with semi-active suspension system, while the vibration of car body is decreased, the running safety of cars is not affected to any significant degree. As a result, the ride quality is much improved with negligible deterioration of the running safety of cars.

• International Journal of Railway
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• v.2 no.4
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• pp.147-151
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• 2009

Railway vehicles equipped with semi-active suspension system can improve the ride quality of car bodies. Semi-active suspension system is usually applied onto high speed train, and therefore higher running safety requirement is proposed. The influence of semi-active suspension system on safety of vehicles running on straight line and curve line is studied, and the influences of sky hook damping coefficient and system time-delay on operation safety of cars fitted with semiactive suspension system is analyzed. The results show that the vehicles equipped with semi-active suspension system, not only the vibration of car body is decreased, it can also give little influence on running safety of cars, as a result, it will not endanger the running safety of cars.

• Journal of the Korean Society for Railway
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• v.15 no.1
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• pp.48-61
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• 2012

It is of great importance to assure the running safety, ride comfort and serviceability in designing the floating slab track for mitigation of train-induced vibration. In this paper, for this, analyzed are the system requirements for the running safety, ride comfort and serviceability, and then, the behavior of train and track at the floating slab track including the transition zone to the conventional concrete slab track according to several main design variables such as system natural frequency, arrangement of spring at transition, spacing of spring isolators, damping ratio and train speed, using the dynamic analysis technique considering the train-track interaction. The results of this study demonstrate that the discontinuity of the support stiffness at the transition results in a drastic increase of the dynamic response such as wheel-rail interaction force, rail bending stress and rail uplift force. Hence, it is efficient to decrease the spacing of springs or to increase the spring constants at the transition to obtain the running safety and serviceability. On the other hand, the vehicle body acceleration as a measure of ride comfort is little affected by the discontinuity of the stiffness at the transition, but by the system tuning frequency; thus, to obtain the ride comfort, it is of great significance to select the appropriate system tuning frequency. In addition, the effects of damping ratio, spacing of springs and train speed on the dynamic behavior of the system have been discussed.

• Journal of the Korean Society for Railway
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• v.10 no.5
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• pp.473-479
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• 2007

Lateral vibration at the tail of KTX train was found during the acceptance test. In order to settle the problem of lateral vibration, the wheel conicity was changed 1/40 to 1/20. However, we should evaluate the running safety of vehicle with 1/20 wheel conicity because modification of wheel conicity may cause the running performance to be worse and critical speed to reduce. In this paper, we calculate critical speed of KTX bogie as wheel conicity increase and analyze the running safety for KTX that has 20 car trainset formation using VAMPIRE. and compare with the test results of KHST to validate analysis results on high speed line. A analysis results show that critical speed of 0.3 wheel conicity is over 375km/h and curving performance of 1/20wheel conicity is better than 1/40. Also, we examinate the running performance of KTX to check out possibility to increase speed of KTX on conventional line. A analysis results show that it is possible to increase up to 10% the speed of KTX on tangent line but KTX on a curved line should be operated with the speed of conventional train.

• The Transactions of the Korean Institute of Electrical Engineers P
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• v.66 no.4
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• pp.224-228
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• 2017

Recently, in order to improve the efficiency of freight transportation on existing lines, a new freight train model is needed to develop urgently. The weight balance of the cargo for the freight vehicle is very important for the stability of the running train and the safe transportation of the cargo. For achieving the cargo weight balance, we proposed a Cargo Balancing Control(CBC) system on the Freight vehicle equipped in between under frame of car body and bogie system. The Cargo Safety Monitoring(CSM) system was designed to supervise status of the Cargo on freight train. The monitoring system can display real time status data from sensors and various signals effectively. We suggested that this paper is a very useful approach for keeping the safety of running freight trains on existing lines.

• Proceedings of the KSR Conference
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• 2000.05a
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• pp.316-323
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• 2000

In railway train operations, a braking distance between two trains must be controlled on their speeds to avoid rear end collisions. The distance is decided by some parameters such that propulsion and braking performance of trains, gradient and etc. When determining this block distance, it is important to consider the two aspects that safety insurance at train running and increase of train running frequency. In this paper, we showed a methodologies of equiblock by consideration gradients and calculated optimal block speeds on the basis of the equivalent block distance.

• Proceedings of the KIEE Conference
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• 2003.11c
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• pp.810-813
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• 2003

The present headway on KNR(Korea National Railway) lines varies from 6 to 10 minutes depending on the each line and by the operation of High Speed line in 2004, the bottleneck would be expected within a few sections such as Daejeon-Daejeon shunting yard which will be the common mute between KTX(Korea Train Express) and conventional trains. Therefore, KNR would like to reduce the headway of the all lines by 4 minutes with the implementation of ERTMS/ETCS on-board system. Where ETCS(European Train Control system), the subsystem of ERTMS, is Automatic Train Protection system for safety train running. This study will be analyze expected braking distance and running time depending on characteristics of conventional passenger and freight trains and high speed train will be operated within electrified conventional line for comparing the headways of ATS(Automatic Train Stop) system and ETRMS/ETCS system within the Daejeon-Daejeon shunting yard section.