• Journal of the Korean Society for Railway
• /
• v.15 no.4
• /
• pp.402-407
• /
• 2012

Since reports on trip delays or incidents often appear as accident articles on the press, the social criticisms and concerns on the safety of the urban railway are increasing. Therefore, a railway authority sometimes adopts an abstract safety goal like "let's build the urban railway to a masterpiece level" or "let's obtain an aeronautic safety level" to make citizens relieved and to alert involved persons. However with a vague goal, it is almost impossible to make an implementation plan systematic which helps the authority academically verify and validate if the goal is achieved or not. In this paper, the features of the railway safety are described and the safety models for securing the safety of the urban railway are surveyed and categorized. Based on the comparisons among the features and limitations of the models, we identify a more practical model which can be applied to the urban railway more effectively.

• KSCE Journal of Civil and Environmental Engineering Research
• /
• v.34 no.3
• /
• pp.1017-1022
• /
• 2014

Since the opening of Seoul Subway Line #1 in 1974, the number of passengers has been increasing. The possibility for passenger's accidents in railway stations has also increased. In order to decrease these kind of accidents, railway operation systems have been automated. Nevertheless, the possibility of a casualty accident in railway stations remains. This study analyzed the type of casualty accidents, casualty accidents by age, sex, pedestrian facility, and passenger type based on the internal data of Seoul Metro. The causes of casualty accidents are also found out. Finally, the establishment of railway safety education program and railway safety experience center are suggested in order to prevent the urban railway casualty accident in advance at railway stations.

• Journal of the Korean Society for Railway
• /
• v.20 no.4
• /
• pp.482-490
• /
• 2017

This study is a railway accident investigation statistic study with the purpose of prediction and classification of accident severity. Linear regression models have some difficulties in classifying accident severity, but a logistic regression model can be used to overcome the weaknesses of linear regression models. The logistic regression model is applied to escalator (E/S) accidents in all stations on 5~8 lines of the Seoul Metro, using data mining techniques such as logistic regression analysis. The forecasting variables of E/S accidents in urban railway stations are considered, such as passenger age, drinking, overall situation, behavior, and handrail grip. In the overall accuracy analysis, the logistic regression accuracy is explained 76.7%. According to the results of this analysis, it has been confirmed that the accuracy and the level of significance of the logistic regression analysis make it a useful data mining technique to establish an accident severity prediction model for urban railway casualty accidents.

• The Transactions of The Korean Institute of Electrical Engineers
• /
• v.58 no.6
• /
• pp.1116-1122
• /
• 2009

ATS(Automatic Train Stop) system makes train stop when it runs over the speed limit and ensure the safe operation of train. Seoul Metro line 2 in Korea, which started its passenger service in 1982, has adopted ATS system for its signaling system. The ATS system has only a train stop function at the time of emergency, and Seoul Metro is planning to replaced them with ATC(Automatic Train Control)/ATO(Automatic Train Operation) system which can provide the dedicated speed control for headway reduction and automatic operation of train. Until all the ATS system is replaced with the new ATC system, both systems are to operate simultaneously at the same metro line. In this situation, ATS system sometimes reveals improper operation: train stops suddenly without any obstacles in front of it. These emergency stops cause interruption of passenger service, and abnormal abrasion of wheels and rail. This paper makes it clear that these interruptions are caused by EMI phenomena between ATS on-board device and ATC wayside device : Signal current flowing in AF track circuit of ATC is turn out to be a EMI source that prevent normal operation of the ATS on-board device. Although the two systems have different frequency-ranges (ATS system has frequency range between $78{\sim}130$[kHz] and ATC system has frequency range between $9.5{\sim}16.5$[kHz]), it turned out that EMI phenomena appears between the both systems. This is investigated by measuring the output signal from ATS on-board device passing over ATC wayside device. The FFT(Fast Fourier Transform) analysis of the signal reveals that AF track circuit signal is transmitted to the ATS on-board device and induce noise causing improper operation. The countermeasures to the EMI phenomena are examined in three ways; blocking EMI transmission, enforcement of EMS (Electromagnetic Susceptibility) of ATS on-board device, and blocking the EMI source. It is suggested that the practical solution be blocking EMI source temporarily, that is breaking AF track circuit signal when the trains with ATS on-board device pass over it. To this purpose, TODS(Train Occupation Detection System) is developed, and has made a success in preventing the EMI problem of Seoul Metro line 2.

• Journal of the Korean Society for Railway
• /
• v.12 no.4
• /
• pp.582-589
• /
• 2009

The energy generated by braking vehicle would simply be converted into waste heat by its braking resistors if no other vehicle is accelerating at exactly the same time. Up to 45% of the tractive power of vehicles capable of returning energy to the power supply can be regenerated during braking and that this energy can be used to feed vehicles which are accelerating at the same time. Such synchronized braking and accelerating can not be coordinated, the ESS(energy storage system, here after) stores the energy generated during braking and discharges it again when a vehicle accelerates. The ESS is able to store and discharge energy extremely quickly, consequently enabling a complete exchange of energy between vehicles, even if they are not braking and accelerating at precisely the same time, as is most frequently the case in everyday service. The energy saving rate is related to the headway. If the headway is long/short, the energy saving goes up/down, When the headway is short, the ESS can not save much regenerative energy. The headway of SeoulMetro line 2 as the worst case is very short in Korea urban transit system. So, the energy saving rate will be very low. If the ESSs are applied to another railway system, we can expect that the effectiveness is better than the results of SeoulMetro line 2. This paper presents effects of energy saving obtained by applying the ESS to SeoulMetro line 2.

• Journal of the Korean Society for Railway
• /
• v.20 no.1
• /
• pp.31-42
• /
• 2017

Many studies have been performed to reduce electric consumption in railway systems. Due to its low conduction loss and high regenerative braking efficiency characteristics, the ESS powered railway system is chosen as a promising candidate for future railway systems. This paper introduces the ESS powered railway system and analyzes current power charge calculation methods that have been set up by KEPCO (Korea Electric Power Corporation). Based on the analysis, this paper proposes two different power charge reduction methods for the railway system. One is to smooth the peaks of traction energy consumption by supplying additional energy to the grid. The other is to save electric charge by reducing electric energy consumed by the railway during the energy peak time, 2 p.m.~5 p.m., which has highest 'Won/kWh' rates. To verify the effectiveness of the proposed method, the power charge of Seoul Metro Line 2 is recalculated using the method.

• Proceedings of the KIEE Conference
• /
• 2009.04b
• /
• pp.177-179
• /
• 2009

It is increased that need of broadband multimedia service to make useful environment for user and to support the operation of railway system. So study of integrated data transmission in a subway and railway is activated. The research deals with pass loss characteristics of 18GHz microwave that is assigned frequency of integrated data transmission in a subway and railway. It is used sample integrated transmission system in subway and railway of KRRI(korea railroad research Institute) at the tunnel and road. Specification of test sample system is blow. It use OFDM modulation, Wireless frequency is 18GHz and 19GHz, Maximum output power is 20dBm, Receive sensitivity is -90dBm. The pass loss exponent and standard variation of road and tunnel is analyzed.

• Proceedings of the KSR Conference
• /
• 2011.05a
• /
• pp.888-894
• /
• 2011

This paper is a study of optimal train driving strategy to minimize the energy consumption. Optimal driving strategy can be analyzed as an optimal problem which have constraints by using Largrangian Function and Kuhn-Tucker condition. We simulate the section between Konkuk University Station and Seongsu Station which is on outer circle line of the Seoul Metro line No.2 by using MATLAB and consider the straight level track and the speed limit.

• Proceedings of the KSR Conference
• /
• 2011.05a
• /
• pp.1148-1154
• /
• 2011

Vending machines to release single-use RF(Radio Frequency) transport cards at Seoul Metro stations are operated under unmanned facility and have release & charge function. This Paper introduces function, configuration of vending machine to release single-use RF transport cards, the basic concepts & overview about vending machine's operating system. And suggests programming procedure to develop OS image of Windows Embedded operating system which is onboard the main board's electronic circuitry.

• Proceedings of the KSR Conference
• /
• 2004.06a
• /
• pp.842-846
• /
• 2004

Both traffic congestion and air pollution in the metropolitan area can be greatly relieved by promoting the use of public transportation with zero emission system. Bus and subway are very convenient means for the people moving in the route areas. But they are not enough to satisfy handicapped or old people to have access to them and also do not solve environmental problems completely. New vehicle system, fuel cell track rapid transit, will be introduced as a countermeasure for such problems in the present paper.