• Proceedings of the KSR Conference
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• 2007.11a
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• pp.595-600
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• 2007

Greater expansion and more frequent operation of the railroad transportation system anticipated due to its characteristics including low cost, safety and mass transportation. Recently, effects on the railway structures due to expansion of newly constructed road, construction of subway, city gas pipeline, communication network, electric power network and construction of other railway underground crossing in accordance with urban planning and organization has influenced safe operation of trains. Accordingly, standard for selection of construction method that will enable construction of more economical and rational subway underground crossing structures by preventing problems occurring at the time of above construction works and accidents in safe operation of trains due to construction in advance is definitively necessary. Although there are numerous construction methods that can be applied at the time of construction of railway underground crossing, there are much difficulties in selection of appropriate construction method that considers characteristics of each construction method on non-excavation type construction method, train operation plan of number of operational routes and on-site circumstances. Therefore, this research aims to present rational standard for selection of construction method for such, and standard for slowdown speed and interception of train when passing the areas of slowdown in sectors under construction.

• Journal of the Korean Society for Railway
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• v.14 no.1
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• pp.66-72
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• 2011

In order to assure the safety of train operation, a safety function analysis corresponding hazardous events of railway accidents and a safety requirement review on operation & management of trains have been performed. The preconditions and train composition requirements such as safety principles and functions that should be essentially considered to enable the safety operation of Urban-Transit trains are clearly presented. On the basis of presented train composition requirements, a rational revise of Urban Railway Operation Rule is proposed. It will be helpful in accident prevention and safety improvement for railway operation.

• Geomechanics and Engineering
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• v.11 no.6
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• pp.757-769
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• 2016

Rail support modulus is an important parameter for analysis and design of ballasted railway tracks. One of the challenges in track stiffness assessment is its dynamic nature under the moving trains which differs it from the case of standing trains. So the present study is allocated to establish a relation between the dynamic and static stiffness of ballasted tracks via field measurements. In this regard, two different sites of ballasted tracks with wooden and concrete sleepers were selected and the static and dynamic stiffness were measured based on Talbot - Wasiutynski method. In this matter, the selected tracks were loaded by two heavy and light car bodies for standing and moving conditions and consequently the deflection basins were evaluated in both sites. Knowing the deflection basins respect to light and heavy loading conditions, both of static and dynamic stiffness values were extracted. Finally two definite relations were obtained for ballasted tracks with wooded and concrete sleepers.

• Proceedings of the KSR Conference
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• 1999.11a
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• pp.46-53
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• 1999

As of July 1999, i,185 lomocotives(excluding metropolitan area electric locomotives) are in Korean National Railroad(KNR). With this limited number of resources assigning locomotives to each trains of timetable is very important in the entire railway management point of view because schedule can be regarded as goods in transportation industry. On a simple rail network, it is rather easier to assign proper locomotives to trains with the experience of operating experts and get optimal assignment solution. However, as the network is getting bigger and complicated, the number of trains and corresponding locomotives will be dramatically increased to rover all the demands required to service all of the trains in timetable. There will be also numerous operational constraints to be considered. Assigning proper locomotives to trains and building optimal cyclic rotations of locomotive routings will result in increasing efficiency of schedule and giving a guarantee of more profit. The purpose of this study is two fold: (1) we consider a planning-level locomotive scheduling problem with the objective of minimizing the wasting cost under various practical constraints and (2) development of implementation prototype program of its assigning result. Not like other countries, i.e. Canada, Sweden, Korean railroad operates on n daily schedule basis. The objective is to find optimal assignment of locomotives of different types to each trains, which minimize the wasting cost. This problem is defined on a planning stage and therefore, does not consider operational constraints such as maintenance and emergency cases. Due to the large scale of the problem size and complexity, we approach with heuristic methods and column generation to find optimal solution. The locomotive scheduling prototype consists of several modules including database, optimization engine and diagram generator. The optimization engine solves MIP model and provides an optimal locomotive schedule using specified optimization algorithms. A cyclic locomotive route diagram can be generated using this optimal schedule through the diagram generator.

• Proceedings of the KIEE Conference
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• 2002.07b
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• pp.1292-1294
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• 2002

In this study, the block section length of the given area has been analyzed to improve the headway which caused by the mixed operation of high speed trains and normal trains on the electrified railway of Dongdaegu to Busan. After establishing the average length of block section and the adjustable average length of block section of Dongdaegu to Busan, it is possible to perform the headway simulation regarding the signal system based on the established length. Although high speed trains as well as low speed trains including freight trains operate together, the experimental results indicate that the modification of the block section length shows the possibility of the improvement of headway.

• Proceedings of the KSR Conference
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• 2011.10a
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• pp.490-497
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• 2011

When operating Express and Standard trains, which run with two different scheduled time, in a single line with limited number of side tracks for overtaking standard trains, it is required to have various modeling methodologies and simulations in order to calculate an optimum headway to maximize the capacity of the line with the best scheduled time. Especially it is inevitable that following trains have to slow down or stop in the middle of their operations due to the preceding trains, in case it is inappropriate controlled about either in which station an overtaking should be taken or how long it should be. This study is to analyze TPS data which have been produced with a simulation program which the team has invented to optimize Express and Standard mixed traffic plan and to introduce an algorism which shows detected conflict data, calculates appropriate dwell time after getting overtaken and helps to decide stations for overtaking.

• Proceedings of the KSR Conference
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• 2004.06a
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• pp.927-934
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• 2004

For the purpose of speed-up of conventional lines with many curves, the introduction and operation of tilting train is under process. Those are Joong-Ang, Jang-Hang and Ho-nam lines etc. Tilting trains can run a curve section faster than existing trains without a significant violation of passenger's comfort and enable to reduce operating time in the lines with many curves. In this study, the trains speeds are evaluated, based on the alignment of conventional line, criteria for passenger's comfort and investigated field conditions of the sections where the curves exist. Decision on whether the alignment(transition line) needs to be modified or not is also made. Relative efficiency on curve sections of tilting train to existing trains is approximately $50\%$ in average.

• Proceedings of the KSR Conference
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• 2007.05a
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• pp.1466-1474
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• 2007

In large station with high density traffic, trains is hardly controlled by CTC but by station dispatcher because CTC has difficulties in monitoring all states of affairs happening within the station such as departs and arrivals of many trains from different lines and shunting trains between yards and platforms, etc. Therefore station dispatcher has to make quick decision about how to schedule all trains including trains to arrive and depart before long. And such decisions become harder when an unexpected delay occurs. This study suggests a mathematical model and algorithm about how to detect in advance and resolve efficiently the conflicts occurring within a station and it will be shown how to reduce delay using our approach by means of analysing the schedule of ChyungRyangRi station.

• Journal of the Earthquake Engineering Society of Korea
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• v.20 no.2
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• pp.103-112
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• 2016

Resonance occurrence conditions are explored by performing dynamic interaction analysis of arch bridge and KTX trains. The target bridge is a 3D tied-arch bridge having span length of 120m. KTX trains consist of two power carriages, two power and passenger carriages and sixteen passenger carriages. When KTX trains run on the target bridge with the uniform speed of 100 to 500km/h, the dynamic responses of the bridge induced by moving trains are obtained from railway arch bridge-train interaction analysis. Two resonance conditions are presented and whether the resonance phenomena occur or not at the suspicious resonance velocities is rigorously investigated through bridge deflections and accelerations and their FFT analysis.

• Journal of Korean Society of Steel Construction
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• v.28 no.3
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• pp.163-171
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• 2016

For railway bridges, serviceabilities such as passenger comfort and train riding safety are important design requirements as well as the structural safety of the bridge. In this paper, dynamic responses of a steel box girder bridge by actual passing trains were measured and analyzed by probabilistic method. Deflections and accelerations data at center of side span were collected for about a month by various types of actual passenger and freight trains. Effects by axle weights, types of trains were analyzed. 100 and 200 years maximum values were estimated by Gumbel probability paper and compared with corresponding requirements in the current design code. Except for some cases of accelerations, estimated values were well below the criteria and exceedance probabilities were very low. More data for longer term and other types of bridges are needed to perform comprehensive analysis on the serviceability of railway bridges.