• Journal of Korean Society of Transportation
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• v.23 no.2
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• pp.75-82
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• 2005

To relieve congestion in the current system of intercity transportation, the Korea decided in 1990 to construct a high-speed railroad between Seoul and Busan and it is now in operation. This new mode of transportation significantly cut travel time between major cities and a trip from Seoul to the southeastern port of Busan. Since the KTX opening, average daily passenger numbers on both the Gyeongbu and Honam lines have increased about 1.3 fold over 2003 levels. As of December 2004, the KTX trains are carrying about 81,000 people a day. On KTX routes, the daily number of airline passengers dropped. Express long-distance bus traffic also dropped by 20% to 30%, while that on short-distance routes (100km or less) increased by about 20%. These figures clearly indicate that the Korean transportation network is becoming railroad-centric. However, the number of KTX passengers is fewer than anticipated possibly due to the Korean economic downturn and the operation of the KTX will leave many existing Saemaul and Mugunghwa train sets idle, which will be put into operation for areas, not covered by the KTX. When all the existing major lines have been electrified, more high-speed rail services will be phased in using direct connections to maximize operational efficiency. And also, the dual management by KTX and conventional rail will be regarded as the promotion of the benefit of the public.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.37 no.8
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• pp.1035-1041
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• 2013

To evaluate the structural integrity and dynamic characteristic of the knuckle part of a KTX anti-roll bar, an experimental and a numerical approach were used in this study. In the experimental approach, the acceleration and strain data for the knuckle parts of the KTX and KTX-SANCHUN anti-roll bar were respectively measured to evaluate and compare its structural dynamic characteristics under the operating environments of the Honam line. In the numerical approach, the evaluation of its structural integrity was conducted using LS-DYNA 3D, and then, the reliability of the finite element model used was ensured by a comparative evaluation with the experiment. The numerical results showed that the stress and velocity field of the knuckle part composed of a layered structure of a thin steel plate and rubber were more moderate than those of the knuckle part made of only a thick steel block owing to the reduction of relative contact between the knuckle and the connecting rod. It was found that the knuckle part made of a thin steel plate and rubber was recommended as the best solution to improve its structural integrity resulting from the elastic behavior of the KTX anti-roll bar being enabled under a repeating external force.

• Journal of the Korea institute for structural maintenance and inspection
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• v.28 no.2
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• pp.61-68
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• 2024

The majority of high-speed railway bridges along the domestic Gyeongbu and Honam lines feature a PSC-box type structure with a span length ranging from 35 to 40m, which typically exhibits a first bending natural frequency of approximately 4 to 5Hz. When KTX high-speed trains transverse these bridges at speeds ranging from 290 to 310km/h, the vibration induced by the trains approaches the first bending natural frequency of the bridge. Furthermore, with the upcoming operation of a EMU-320 high-speed train and the anticipated increase in the speeds of these high-speed trains, there is a need to analyze the dynamic response of high-speed railway bridges. For this, based on measured responses from actual railway bridges, a numerical model was constructed using a numerical model updating technique. The dynamic response of the updated numerical model exhibited a strong agreement with the measured response from the actual railway bridges. Subsequently, this updated model was utilized to analyze the dynamic response characteristics of the bridges when KTX and EMU-320 trains operate at increased speeds. The maximum vertical displacement and acceleration at the mid-span of the bridges were also compared to those specified in the railway design standard with the increasing speed of KTX and EMU-320.

• Proceedings of the KSR Conference
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• 2011.10a
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• pp.2821-2829
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• 2011

Since the KTX was in operation in 2004, a number of researches on increasing the train speed have been conducted. Currently, the Honam High-speed train system is designed for the operation velocity of 350km/h. The societal demand expects higher operation speed, whereas the existing construction method and design specification are questioned in the KTX operation in the velocity over 350 km/h. In this study, a full-scale model test was conducted to obtain the preliminary data that is necessary to understand deformation characteristics of the reinforced road bed and the subgrade layers. In the full-scale model test, direct arrival seismic tests, crosshole seimic test, in-situ bender element test and sensing bar test were employed to measure the stiffness and deformation of the trackbed. The systematic analysis on the different set of measurements enhances the understanding of the behavior of the trackbed.

• Journal of the Korean Society for Railway
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• v.19 no.5
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• pp.576-584
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• 2016

In this study, we measured the air tightness of a train using pressure variation in tunnels. To estimate the air tightness of a train is essential to comprehend the pressure variation of the cabin because air tightness is strongly related with ear discomfort. If we can determine the air tightness, we can predict the pressure variation of the cabin. Also, ear discomfort is a problem that can be caused in a high speed train, as well as in Korea's Great Train Express. In this study, we compared the various international standards for ear discomfort and estimated the air tightness of each vehicle based on experimental data obtained using the ITX, KTX and KTX-sancheon(honam) vehicles. The internal pressure variation of the trains is numerically calculated using the air tightness value. The results are good compared to the experimental results. Instead of flap type ventilation, in the future, continuous ventilation equipment will be needed for speed-up.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.11 no.7
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• pp.2534-2540
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• 2010

In this paper we propose contents and results on installation and commissioning test for ATP on-board unit, which has propelled as one of the research projects, so called, "Reliability assessment and operation technology development for Korean-type tilting trains" in order to ensure the safety and operation efficiency of tilting trains. In KRRI, we have developed tilting trains for the speed-up of existing lines and for the passenger service improvement where the KTX is not available. And we also make progress the operation trial test at the speed of 10km with the use of ATS units, used in existing lines, for the purpose of the reliability assessment of the developed tilting trains. In MLTM, they have decided to accelerate the speed at more than 200km/h for the 7 existing lines including Jungang-line and Chungbuk-line where KTX has not operated. According to this decision, Train control system is to be changed from ATS to ATP. We should install an ATP on-board unit in tilting trains and verify the operational suitability. Therefore, we have installed and tested the same ATP on-board unit on tilting trains that used in the ATP construction project on Gyeongbu-line and Honam-line.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.18 no.11
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• pp.697-704
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• 2017

This study was carried out to investigate and alleviate the vibration problem of commercial high-speed trains. First, the measurement of the carbody vibration was performed, in order to determine the vibration level of the high-speed train. The measurement result showed that the vibration level of the driver cab was higher than that of the passenger car and that the vibration became bigger toward the trailing end of the train. The vertical vibration of the driver cab and passenger car was larger than the transverse vibration, and the maximum value of the vibration in the ballast section was larger than that in the concrete section. A dynamic analysis was carried out to improve the vibration of the KTX-Sancheon train. The results of the analysis showed that it is necessary to reduce the vibration of the driver cab and both ends of the passenger cars. To reduce the vibration of the driver cab, it was recommended that the stiffness of the secondary coil spring be reduced and the damping coefficient of the secondary vertical damper be increased. It was found that the failure of the suspension system could be the origin of the vibration problem of the high-speed train. The proper management of wheel wear plays an important role in the improvement of the operation efficiency and reduction of the carbody vibration of high-speed trains, and research is underway to change the present wheel profile to increase the mileage between wheel turning.

• Journal of the Korean Society for Railway
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• v.13 no.4
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• pp.376-381
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• 2010

In this study, field measurements on KTX, Nuriro and TTX train have been conducted at Kyeongbu and Honam line to predict the wind gust under train at the speed-up of major conventional railway lines using Kiel-probe array and multi-channel pressure scanning system. The results show that the average wind velocity during train passage normalized by train speed is independent to train speed, thus the wind gust for a given train type at the speed-up condition could be predicted. The relationship between the shape of underbody and the characteristics of the underbody wind gust has been discussed.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.22 no.10
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• pp.864-869
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• 2009

The measurement of contact wire uplift in electric railways is one of the most important test parameters to accepting the maximum permitted speed of new electric vehicles and pantographs. The contact wire uplift can be measured over short periods when the pantograph passes monitoring stations. In this paper, a high-speed image measurement system and its image processing method are being developed to evaluate dynamic uplift of overhead contact wires caused by pantograph contact forces of Korea Tilting Train eXpress (TTX) and Korea Train eXpress (KTX). The image measurement system was implemented utilizing a high-speed CMOS (Complementary Metal Oxide Semiconductor) camera and gigabit ethernet LAN. Unlike previous systems, the uplift measurement system using high speed camera is installed on the side of the rail, making maintenance convenient. On-field verification of the uplift measurement system for overhead contact wire using high speed camera was conducted by measuring uplift of the TTX followed by operation speeds at the Honam conventional line and high-speed railway line. The proposed high-speed image measurement system to evaluate dynamic uplift of overhead contact wires shows promising on-field applications for high speed trains such as KTX and TTX.

• Journal of the Korean Society for Railway
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• v.11 no.6
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• pp.575-580
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• 2008

When constructing a high-speed railroad, the reduction of the distance between track centers and the width of track bed will save the construction cost. However the shortening the distance between track centers may cause the stability problems due to higher wind pressure. Therefore the extensive technical review and aerodynamical study should be performed to determine the adequate distance between track centers. In this study, the impact that the increase in wind pressure due to the change of aerodynamic phenomena with the change of the distance between track centers may have on two trains passing by each other was predicted, and the stability of train operation was analyzed in order to review the distance between track centers suitable to Honam HSR trains. And we estimated the aerodynamical effects by the results of the field test.