• Journal of the Korean Society for Railway
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• v.15 no.2
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• pp.185-192
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• 2012

Line planning is to determine the frequency of trains on each line to satisfy origin-destination demand while minimizing total operation cost. However, different from the line planning in passenger transportation, it is more important at which intermediate stations each train should be stopped and shunted because the freight car handling works like drop-off or(and) pick-up can incur much time and high cost so that the delay deteriorates the quality of rail freight transportation service. We present an optimization model for constructing line plan in rail freight transportation to simultaneously minimize the train operation cost and total transportation time of freights. And we suggest a column generation approach for our problem, which can solve the real network instances in reasonable computation times.

• Journal of the Korean Society for Railway
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• v.17 no.2
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• pp.140-147
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• 2014

Line planning is an important step to determine the optimal frequencies of trains given the forecasted demand for each train type. The main input data for line planning is the leg traffic demand which can be derived using suitable traffic assignment models. However most assignment models require a line plan, in other words, train frequencies or headways, so that inconsistent results just by the procedural approach to find an optimal line plan after determining leg traffic can be avoided. This paper suggests a unified model that can consider the traffic assignment and line planning, simultaneously. We further provide an elaborated approximation algorithm and, finally, provide experimental results determined for the Korean railway network.

• Journal of Korean Society of Transportation
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• v.23 no.6 s.84
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• pp.115-125
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• 2005

The line planning problem is to determine the origin and destination stations of the lines with their frequencies so as to meet the OD demands. Since the advent of high speed trains, Korea railway is confronted with the urgent difficulty to reconstruct the line configuration with the frequencies of each line and each fleet type so the demands could be newly created as well as satisfied. Furthermore. the existing trains except the high speed trains suffer from a longer traveling time than before. Now, to reduce the passenger traveling time, the trains with the various halting patterns are run in the same line. Therefore, it is necessary to develop a new line planning model to consider the various halting patterns. Most of studies find the frequencies of each lines which meet the link traffic loads or minimum link frequencies. But these are based on the assumption of all stop patterns. Furthermore, it is not easy to include the actual constraints as like the minimum number of stops at a station, the maximum number of stops or a train, etc. We develop the line planning model considering not only the various halting patterns but also the actual constraints which is based on the multicommodity network flow model with the additional constraints.

• Journal of Korean Society of Transportation
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• v.20 no.7
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• pp.117-133
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• 2002

열차운영계획은 수송수요 산정, 운행노선계획, 열차시간표 작성 기관차 및 인원의 할당 등 광범위한 내용을 포괄하고 있으나, 본 논문에서는 계획의 초기단계에서 결정 가능한 운행노선계획을 대상으로 범위를 설정하였다. 운영목표에 따른 전략은 사용자, 운영자, 사회전체의 입장에서 고려될 수 있는데, 이러한 전략에 의해 운행 될 수 있는 열차운행패턴을 운영비용의 최소화, 통행시간의 최소화. 운영자 수익의 최대화 모형으로 해결하고자 하였다. 2004년 이후에 운행이 예상되는 고속철도/기존철도는 운영계획의 변경이 예상되는 바, 상기의 목표에 따라 열차운영패턴을 작성하여 개발된 효과척도의 적용을 통해 정책적인 적용가능성을 평가하였으며 기존 계획된 철도청의 운영계획과도 아울러 비교, 최적대안을 선정하였다. 본 고에서는 수리계획모형인 비선형정수계획모형(MINLP)으로서 국내 철도망에 부합하는 운영계획을 작성하였으며, 이에 따른 열차-km는 수익최대화 모형, 인-km는 철도청의 열차운영계획이 가장 많은 것으로 나타났다. 인-hour는 수익 최대화 모형과 통행시간 최소화 모형이 가장 적은 것으로 나타났는데, 이는 장거리 노선의 편성이 증가된 것으로 사료된다. 이러한 결과를 산출함에 있어. 어려운 점은 각 구간의 기하급수적 증가, 결정변수의 초기값 선정 등이 있으나, 그동안 연구된 각종 경험적 기법의 적용과 실제 편성 가능한 변수의 적용을 통해 이를 해결하였다. 추후 설정된 모형의 비교에 적합한 효과척도의 개발과 전국적으로 사례구간의 확장 및 모형의 최적대안 선택 시 효과척도의 가중치에 대한 연구가 필요할 것으로 사료된다.

• Journal of the Korean Society for Railway
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• v.17 no.6
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• pp.466-473
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• 2014

Recently, there is has been significant interest in the allocation systems of rail track capacities with considerations of the multiple train operating companies. The system indicates both a well-defined procedure and an algorithmic method to allocate the rail track capacities. Among them, this study considers the algorithmic method to derive the optimal timetable for the trains, which the companies propose together with their arrival and departure times at each station. However, most studies have focused on the adjustment of the departure and arrival times without conflicts, which could result in incompatible allocations with the line plan, which would result in an insufficient number of trains on each line to satisfy the demands. Our study presents a new optimization model and algorithm for the allocation problem in order to reflect the predetermined line plan. Furthermore, we provide the experimental results that were applied to the Korean high-speed railway network including the Suseo lines.

• Journal of the Korean Society for Railway
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• v.20 no.4
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• pp.529-538
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• 2017

There has been much interest in optimizing the halting patterns of high-speed trains, for example by introducing more non-stop trains to supply faster train service to the passengers, which could later bring about a discussion about introducing new high speed train service with differentiated price and service. In general, halting patterns can be considered by constructing an efficient line plan, in which all demand should be covered and the total travel time can be reduced as much as possible. In this study, we present a two-step process based on two optimization models. One is to minimize total kilometers of trains to run on each route ; this will be done using a line planning model under the assumption of all-stop patterns. Then, in the next step, the all-stop patterns are optimally decomposed into several halting patterns in order to minimize the total travel time. We applied the two-step process to the latest demand data in order to develop KTX halting patterns as well as to determine the frequency of each line and compare the current line plan with the optimized one.

• Journal of Korean Society of Transportation
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• v.31 no.2
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• pp.80-89
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• 2013

The purpose of this research is to optimize the line planning of the intercity passenger railway. In this study, the line planning problem has been formulated into a mixed integer programming by minimizing both user costs (passenger's total travel time) and operator costs (operation, maintenance and vehicle costs) with multiple train types. As a solution algorithm, the branch-and-bound method is used to solve this problem. The change of travel demand, train speed and the number of schedules have been tested through sensitivity analysis. The optimal stop-schedules and frequency as well as system split with respect to each train type have been found in the case study of Kyoung-bu railway line in Korea. The model and results of this research are useful to make a decision for railway operation strategy, to analyze the efficiency of new railway systems and to evaluate the social costs of users and operators.

• The Journal of The Korea Institute of Intelligent Transport Systems
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• v.17 no.6
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• pp.14-24
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• 2018

Pedestrian movement of passengers using smart card within stations can be divided into three types of activities - straight ride and alight, line transfer, and station transfer. Straight ride and alight is transfer activity for which the card terminal and embarking line are identical. In this case, straight ride occurs at the origin station and straight alight occurs at the destination station. Line transfer refers to activity in which the subway line embarked on by the passenger is different from that which is disembarked. Succinctly, line transfer is transfer at a middle station, rather than at origin or destination stations. Station transfer occurs when the card terminal line and embarking line are different. It appears when station transfer happens at the origin station as starting transfer, and at the destination station as destination transfer. In the case of Metropolitan smart card data, origin and destination station card terminal line number data is recorded, but subway line data does not exist. Consequently, transportation card data, as it exists, cannot adequately be used to analyze pedestrian movement as a whole in subway stations. This research uses the smart card data, with its constraints, to propose an analysis model for passenger pedestrian movement within subway stations. To achieve this, a path selection model is constructed, which links origin and destination stations, and then applied for analysis. Finally, a case study of the metropolitan subway is undertaken and pedestrian volume analyzed.

• Journal of the Korea Society for Simulation
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• v.20 no.3
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• pp.89-100
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• 2011

The MAGLEV (Magnetically Levitated Vehicle) system, which is under commercialization as a new transportation system in Korea, is operated by means of unmanned automatic control system. Therefore the plan of train operation should be carefully established and validated in advance. In general, when making the train operation plan, the statistically predicted traffic data is used. However, traffic wave can occur when real train service is operated, and the demand-driven simulation technology is required to review train operation plans and service qualities considering traffic wave. This paper presents a method and model to simulate the MAGLEV's operation considering continuous demand changes. For this purpose, we employed the discrete event model which is suitable for modeling the behavior of railway passenger transportation, and modeled the system hierarchically using DEVS (Discrete Event System Specification) formalism. In addition, through the implementation and experiment using DEVSim++ simulation environment, we tested the feasibility of the proposed model and it is also verified that our demand-driven simulation technology could be used for the prior review of the train operation plans and strategies.

• The Journal of The Korea Institute of Intelligent Transport Systems
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• v.21 no.3
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• pp.1-17
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• 2022

Accurate analysis of the causes of metro rail traffic congestion provides a means of addressing issues arising from metro rail traffic congestion in metropolitan areas. Currently, congestion analysis based on counting, weight detection, CCTVs, and mobile Wi-Fi is limited by poor accuracies or because studies have been restricted to single routes and trains. In this study, a train congestion analysis model was used that includes the transfer and multi-path behavior of metro passengers and train operation plans for metropolitan urban railroads. Analysis accuracy was improved by considering traffic patterns in which passengers must wait for next trains due to overcrowding. The model updates train crowding levels every 10 minutes, provides information to potential passengers, and thus, is expected to increase the social benefits provided by the Seoul metropolitan subway