• Structural Engineering and Mechanics
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• v.46 no.5
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• pp.713-734
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• 2013

Bridges are vital components of the railroads. High speed of travel, the periodic and oscillatory nature of the loads and the comparable vehicle bridge weight ratio distinguish the railway bridges from the road bridges. The close proximity between estimations by some numerical methods and the measured data for the bridge-vehicle dynamic response under the moving load conditions has boosted the confidence in the numerical analyses. However, there is hardly any report regarding the responses of the railway bridges under the effect of the trains entering from the opposite directions while running at unequal speed and having dissimilar geometries. It is the purpose of this article to present an analytical method for the dynamic analysis of the railway bridges under the influence of two opposing series of moving loads. The bridge structural damping and many modes of vibrations are included. The concept of modal superposition is used to solve for the system motion equations. The method of solution is indeed a computer assisted analytical solution. It solves for the system motion equations and gives output in terms of the bridge deflection. Some case studies are also considered for the validation of the proposed method. Furthermore, the effects of varying some parameters such as the distance between the bogies, and the bogie wheelset distance are studied. Also, the conditions of resonance and cancellation in the dynamic response for a variety of vehicle-bridge specifications are investigated.

• International Journal of Railway
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• v.9 no.1
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• pp.10-14
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• 2016

Life cycle cost analysis is compulsively required for the system operation. System operation costs are consisted of acquisition, operation, maintenance and so on. In the beginning of the system planning, we need to take into account of various costs following the system operating. To implement LCC, we need to analyze system life cycle to identify all costs during system life. The costs can be divided into three parts. The first part is purchasing cost, the second for operating cost and the last for disposal cost. The second operating cost can be decomposed of operating cost included labor, energy consumption cost for system running, maintenance costs to keep systems healthy, delay cost caused from maintenance and hazard cost, and so on. In this paper, we carried out for railway locomotives which operate over more 30years and which cost about 10 million USD. We decompose the life cycle of the locomotives and break down the locomotives into subsystems to require maintenance or not, and subsystems to need energy or not. We showed how to decide optimal locomotives through cost identification and system breakdown.

• The Journal of the Korea institute of electronic communication sciences
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• v.13 no.5
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• pp.1065-1070
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• 2018

These days there are many researches on the vision based technology using deep learning. The lots of studies on the intelligent operation and maintenance for railway station system used technologies with vision analysis function. This paper analyzes the papers which studied the intelligent station system with vision analysis function for passengers and facilities monitoring, platform monitoring, fire monitoring, and effective operation and design. Also, this paper proposes research which uses the more powerful vision technology with deep-learning for smart railway station system.

• Journal of Korea Technology Innovation Society
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• v.3 no.3
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• pp.1-17
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• 2000

This paper shows the institutional limits of technological innovation at the railway package service, that is the limits of introducing the package express system. The railway package service, owned by government and operated by D company, has been suffered severe operating loss since early 1990's. The package express system supported by information network and co-working with inner city quick service might be an solution for the railway package service. But there are several obstacles such as labor union and the rigidities of the Korean National Railroad of government agency.

• Proceedings of the KIEE Conference
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• 2005.07b
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• pp.1592-1594
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• 2005

This paper presents a method to construct a supervisory monitoring system for railway signaling devices which can provide the real-time operation information of signalling devices to several maintenance depots. Spying technique has been applied to acquire the real-time data transmitted among railway signaling devices without interfering the railway signalling system function.

• Journal of the Korean Society of Safety
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• v.24 no.3
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• pp.96-101
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• 2009

In this study, a risk-appearance frequency evaluation model for railway level-crossing accidents is developed with the frequency estimation based on the accident history. It follows the worldwide common safety management approach and reflects the operation conditions and accident properties of the domestic railway system. The risk appearance frequency evaluation process contains a development of accident scenarios by defining the system configurations and functions, and a frequency estimation of hazardous events based on the accident history. The developed model is verified with the accident history during 5 years('03-'07) for 3 hazardous events: 'Being trapped in level crossing(Hl)', 'Crossing during warning signal(H2)' and 'Breaking through/detouring the barrier(H3)'. This risk appearance frequency evaluation model will be combined with a consequence evaluation model so as to offer full risk assessment for the railway accident. The accident risk assessment will contribute to improving the safety management of the railway system.

• Proceedings of the KIEE Conference
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• 2005.04a
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• pp.241-243
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• 2005

The study for ubiquitous computing infra is proceeding actively, it make possible to use service and access network anywhere, anytime because of wire/wireless communication technology and progress of hardware. Domestically, study for the network mobility support technology which is the key technology for future ubiquitous computing realization have progressed, but that is insufficient. Especially, there is no study for independent mobility support study about railway wireless network. So, this study propose network mobility management technology for mobile network infra in railway and proper network model in train.

• Proceedings of the KSR Conference
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• 2003.05a
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• pp.533-541
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• 2003

This paper shows the results of train system engineering technology and exterior and interior design of a prototype test train(HSR 350X) which was developed in R&D project titled 'Development of High Speed Railway Technology'. The prototype test train, which has two power cars, two motorized trailers and three trailers, is now being tested on high speed line.

• Smart Structures and Systems
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• v.26 no.5
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• pp.591-603
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• 2020

Dynamic deflection monitoring is an essential and critical part of structural health monitoring for high-speed railway bridges. Two critical problems need to be addressed when using inclinometer sensors for such applications. These include constructing a general representation model of inclination-deflection and addressing the ill-posed inverse problem to obtain the accurate dynamic deflection. This paper provides a dynamic deflection monitoring method with the placement of optimal inclinometer sensors for high-speed railway bridges. The deflection shapes are reconstructed using the inclination-deflection transformation model based on the differential relationship between the inclination and displacement mode shape matrix. The proposed optimal sensor configuration can be used to select inclination-deflection transformation models that meet the required accuracy and stability from all possible sensor locations. In this study, the condition number and information entropy are employed to measure the ill-condition of the selected mode shape matrix and evaluate the prediction performance of different sensor configurations. The particle swarm optimization algorithm, genetic algorithm, and artificial fish swarm algorithm are used to optimize the sensor position placement. Numerical simulation and experimental validation results of a 5-span high-speed railway bridge show that the reconstructed deflection shapes agree well with those of the real bridge.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.66 no.6
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• pp.975-980
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• 2017

Overhead catenary system of electric railway has overlap sections which devide and tighten trolley wire supplying electric power to train, where current collection performances may become worse according to railway speed-up. Current collection tests conducted at 400 km/h test-bed section of Honam high-speed railway show that balanced line arrangement at overlap section is needed to secure current collection without arc generation between trolley wire and train current collection device. This paper proposes a design procedure of the overlap section to allow for tension increase and uplift of the trolley wires according to railway speed-up. By applying the proposed procedure to the overhead catenary system of Honam high-speed railway, it is suggested that the minimum span length should be 33.2 m for railway speed-up to 350 km/h and 43.7 m for speed-up to 400 km/h.