• Proceedings of the KSR Conference
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• 2011.10a
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• pp.754-760
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• 2011

In the DC traction system, a large load current of electric railcar leads to a voltage drop when a vehicle starts, and the regenerative power generated by brake system increases the catenary voltage. To minimize the voltage fluctuation during the train operation and make use of the regenerative power, several types of energy storage systems are being studied. The energy storage system that is being recently introduced consists of the supercapacitors for energy storage and the bi-direction DC/DC converter for charge/discharge control. The efficiency of the energy storage system depends on the train operation pattern. In this paper, the operation efficiency of the energy storage system was quantitatively analyzed via simulation study taking consideration of the train operation patterns. The simulation was conducted changing the headway of trains with the energy storage system that uses the bi-direction DC/DC converter and supercapacitor. The simulation results showed that the operation efficiency of the energy storage system increases as the headway increase.

• Journal of Korean Society of Transportation
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• v.8 no.2
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• pp.99-107
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• 1990

This research addresses the effect of heavy vehicles (especially trucks) in terms of passenger car Equivalents from a capacity viewpoint. A formulation that estimate PCE in this paper is derived by introducing appropriate headway measurements into Huber's general equation for PCEs. In this equation, PCE value is expressed in terms of headways for four different kinds of pairs; pairs of leading and following vehicles ; P-P, P-T, P-T, T-T. The mean value of headway for each case is estimated through the regression analysis. Finally, the approach used in this research was compared with macroscopic approach which analyzed a speed-density relationship to evaluate PCE.

• Proceedings of the KSR Conference
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• 2005.05a
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• pp.831-835
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• 2005

In a signal control of the railway system, the first objective is to guarantee a safety of the train operation, and the second is to increase a frequency(a capability of the transportation) of the train operation. In order to express the capability of the transportation a terminology what is called a railroad line capacity is employed. The railroad line capacity means a maximum frequency of the train operation in a possible schedule of the one way operation for one day. During the last several years an improvement in the facilities of the train operation (railroad line extension, improvement in the stations, improvement in the signal facilities) has been achieved to increase the railroad line capacity. In this paper the authors deal with the case analysis which try to shorten headway and which has an impartible relation with increasing of the railroad capacity

• Proceedings of the KSR Conference
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• 2005.11a
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• pp.65-71
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• 2005

본 논문에서는 PRT(Personal Rapid Transit) 시스템의 성능과 시스템의 안전에 영향을 미치는 PRT 시스템의 운전시격(Headway)에 대해서 다룬다. 어떤 차량과 다음 차량과의 운전 간격을 나타내는 운전시격은 대중교통수단에서 교통 혼잡의 문제를 풀 수 있는 중요한 단서가 되는 성로용량을 평가하는 중요한 인자들 중의 하나이다. 운전시격을 결정하기 위한 중요한 인자들에는 고장 차량의 감속비, 고장차량의 후미에 있는 차량의 비상 제동 감속비, 차량의 선로속도, 차량의 제동을 위한 지연시간 등이 있다. 이들 인자들을 이용한 간단한 해석적 방정식은 차량의 선속도, 감속도와 운전시격에 대한 상관관계를 예측할 수 있도록 해준다. 본 논문에서는 간단한 해석 방정식을 이용한 수치 해석적 방법을 통해서 최소 운전시격에 대한 평가를 예를 간단한 모의시험을 통해서 보인다.

• Proceedings of the KSR Conference
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• 2006.11b
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• pp.1461-1467
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• 2006

In case of accidents at the line of Seoul-Pusan high speed railway, high speed train should be operated with making a detour by using existing Seoul-Pusan railroad. For Dae-jeon$\sim$Dae-Gu section which has fragile structures, following points are investigated. In operating existing train, train running time is analyzed by the case of only high speed train being in service and the case of high speed train being in service on condition that existing train is operated. Also the possibility about operation on present train headway and train headway that is applicable to operation and vocational problems would be examined.

• The Transactions of the Korean Institute of Electrical Engineers B
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• v.52 no.8
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• pp.397-404
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• 2003

In part I, we studied only step speed control for train, the second part extended to beacon signaling system and moving block system. With the calculated braking distance in part I, part II showed how to reduce headway using the beacon signaling system and moving block system, revealed that the beacon system has a braking distance advantage for sighting allowance with compared to step speed control, proposed beacon installation interval and revealed the braking distance with moving block system being nearly approached to train pure braking distance. We compared three different train control system to decide the best signaling system for a given condition and obtained the result that three systems have a same headway near 10～13 steps speed control.

• Proceedings of the KIEE Conference
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• 2003.11c
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• pp.814-817
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• 2003

Assuming that life of urban transit signalling is about 20 years with the flow of technology development, Seoul urban transit will be required to prepare for improvement soon. The highly developed countries preceding several levels rather than Korea are faced with commercial service which uses RF, ATC and ATO in Train Control System. European highly developed countries in the field of railroad have been progressing standardization and technology development of signalling associated with related manufacturers for direct operation between nations. For that, a effective train control system with radio beyond control levels by the existing wayside-onboard communication is in a developed and used stage. The systems which advanced countries have been progressing seem to be applied to domestic within 5 years from now. At present, there are no countries using CBTC for service throughout the world. So, this is investigated to focus on the routes ready to be installed with completed CBTC and trying to introduce the technology. Especially, considerations for economic aspect are mainly reviewed about controlling ability of headway, flexibility, extension aspect and construction cost on the basis of paper examined in NYCT.

• Proceedings of the KIEE Conference
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• 1995.07a
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• pp.451-454
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• 1995

Increasing the transfortation efficiency is very important issue in railway system. Speed-up of train and shortage of headway can be its solution. Headway can vary with blocksection length, characteristics of the railway and signalling systems. Safety braking distance needed for passenger's safety is very important factor in block section division method. In this study, basic block section division program was developed with the differential ratio of braking distance resulted by grade value of the track. More complete block section division program is going to be developed by the help of experienced experts.

• Journal of the Korean Operations Research and Management Science Society
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• v.38 no.3
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• pp.37-50
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• 2013

The purpose of this study is to determine the indicators and the criteria to classify types of train delays of high-speed rail in South Korea. Types of train delays have divided into the chronic delays and the knock-on delays. The Indicators based on relevance, reliability, and comparability were selected with arrival delay rate of over five minutes, median of arrival delays of preceding train and following train, knock-on delay rate of over five minutes, correlation of delay between preceding train and following train on intermediate and last stations, average train headway, average number of passengers per train, and average seat usages. Types of train delays were separated using the Ward's hierarchical cluster analysis. The criteria for classification of train delay were presented by the Fisher's linear discriminant. The analysis on the situational characteristics of train delays is as follows. If the train headway in last station is short, the probability of chronic delay is high. If the planned running times of train is short, the seriousness of chronic delay is high. The important causes of train delays are short headway of train, shortly planned running times, delays of preceding train, and the excessive number of passengers per train.

• Journal of Korean Society of Transportation
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• v.33 no.1
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• pp.90-99
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• 2015

The climate of Korea has clear rainy and dry season due to seasonal wind. In general, The rainy season in Korea is from early summer through to early fall. And precipitation accounted for more than half of the total annual rainfall in this period. This study is aiming to analysis of variation in saturation flow rate at signalized intersection during rainfall. The range of spatial is urban signalized intersections in Seoul and temporal is rainfall or ideal condition in daylight. Traffic data are collected through CCTV of Seoul Metropolitan Police Agency, and on-site video recordings directly. Weather condition data are collected from the Korea Meteorological Administration. In addition, the value of saturation headway and saturation flow rate, in rainfall condition, are derived through video frame analysis. As a results of analysis, decrease of saturation flow rate and increase of saturation headway during rainfall were confirmed by comparison with non-rainfall. The higher rainfall rate is, the more decreased saturation flow rate at the intersections. Rainfall rate is divided three area by the results of statistical test, and saturation flow rate decrease 7%, 17%, 21%, respectively.