• Journal of the Korean Society for Railway
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• v.12 no.6
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• pp.1018-1023
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• 2009

This paper describes a reduction in the peaks of traction energy for metro railways in timetabling. We develope a mixed integer programming (MIP) model, which minimizes the number of trains running simultaneously. We suggest two approaches. In the first approach, we use the commercial MIP solver, CPLEX. In the second approach, we propose a heuristic algorithm. We apply both methods to the current daily timetable of the Korea Metropolitan Subway. We determine an optimal solution, which results in an improvement of approximately 25% over the current timetable.

• Proceedings of the KSR Conference
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• 2009.05a
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• pp.1383-1389
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• 2009

This paper describes an Energy Efficient Timetabling Problem(EETP). In these days, the researches on development of an energy efficient railway systems are highlighted over the world. The departures occurred in an electrical power feeding circuit at the same time are necessary to be reduced as far as possible, to minimize the energy consumption. The paper addresses the operational requirements and facility restrictions to construct a mathematical model for EETP. In addition, it suggests several types of objectives for the model.

• Journal of the Korean Society for Railway
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• v.14 no.2
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• pp.167-173
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• 2011

This paper considers the problem of revising train departure time to reduce electric power consumption of mass rapid transit (MRT) railways. The motion of a train running between stations is divided into three phases: traction, coasting, and deceleration phases. The traction phase requires high electric power to operate MRT railways. In the coasting phase, the train moves stably by consuming little or no power. The deceleration phase is a braking mode and produces some electric power called regenerated brake power owing to inertia force for the train generated In the traction and coasting phases. The regenerative energy can be used by other accelerating trains within a specific range from the train and thereby the power consumptions of train can be reduced. We developed a mixed integer programming model to solve the problem. To validate the suggested model, a computational experiment was conducted using real data from Korea Metropolitan Subway.