• International Journal of Safety
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• v.9 no.2
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• pp.29-34
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• 2010

When doing maintenance works at the trackside of railway, the method which delivers information on approaching of train to maintenance workers through alarm devices such as the flag or indication light, etc., is being used by locating persons in charge of safety alarm in addition to the maintenance workers at fixed distances in the front and rear of the workplace. Workers maintaining at the trackside may collide with the train since they cannot recognize the approach of train although it approaches to the vicinity of maintenance workplace because of the sensory block phenomenon occurred due to their long hours of continued monotonous maintenance work. The clash or rear-end collision accidents between many maintenance trains called motor-cars can be occurred since there are cases where the signal systems for safe operation of motor-car such as track circuit etc. are blocked or not operated normally. We developed the new safety equipment for protection of trackside maintenance workers using radio frequency signals and bidirectional detection mechanism. The developed safety equipment must analyze the several operational mechanism for each different operation situations. In this paper the analysis results are represented.

• Proceedings of the KIEE Conference
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• 2001.07b
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• pp.1257-1259
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• 2001

In this paper, the diagnosis method for AC traction motor is to reduce their maintenance loads. We tried to apply this method to maintenance of traction motor in railway vehicle. Sample coils for stator of traction motor were tested by accelerative thermal degradation which composed of heat, vibration, moisture, and overvoltage applying. Reliability and expected life were evaluated on the insulation system for 200 class traction motor.

• Journal of Korean Society for Quality Management
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• v.41 no.2
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• pp.301-322
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• 2013

Purpose: This study aims to determine the needs of customers who use railroads as a mode of transportation and propose customer-oriented improvements in railroad technology by making connections between customer needs and railroad technology. Methods: We primarily used two methods for this study, AHP and QFD. First, AHP was used to evaluate the relative importance among the different components of railroad technology. Second, the QFD was applied to make a link between customer needs and railroad technology. Results: Railroad technology is largely divided into development, maintenance, and support. Empirical results showed the following improvement priorities in development, vehicle, system, line, signal/communication, power, and structure, in maintenance, vehicle, signal/communication, line, process, power, and structure, and in support, safety/precaution, management, environmental energy, operations/logistics, and station. Conclusion: Recognizing limitations in measuring the level of railroad technology when using the existing 'Technology Growth Model,' we used AHP and QFD to explore improvement directions for customer-oriented railroad technology. By offering customer-oriented services based on this study, railroad service providers will be able to acquire competitive advantage in the market.

• Journal of the Korean Society for Railway
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• v.8 no.6 s.31
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• pp.544-549
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• 2005

Nowadays, most of bridge networks are complete or close to completion. The biggest challenge railroad./highway agencies and departments of transportation face is the maintenance of these networks, keeping them safe and serviceable, with limited funds. To maintain the bridges effectively, there is an urgent need to predict their remaining life from a system reliability viewpoint. And, it is necessary to develop the maintenance models based on system reliability concept. In this paper, maintenance models are developed for preventive maintenance and essential maintenance by using system reliability and lifetime distributions. The proposed model is applied to an existing railroad bridge. The optimal maintenance strategy of this bridge is obtained in terms of services life extension and cumulative maintenance cost.

• Journal of the Korean Society for Railway
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• v.20 no.2
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• pp.275-287
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• 2017

During the feasibility study of new rail lines, maintenance cost of railway infrastructure has mostly been estimated based on the track length and on simplified parameters; however, the estimation reliability can be improved by employing the correction factor from UIC 715, as well as the line classification in UIC 714. The correlations between maintenance cost and various parameters such as weighted track length based on line classification, radius of curvature, gradient and worn -out rate have been analyzed according to the case studies. Prediction of the maintenance cost has been carried out using the cost data, which were representative of the whole cost data; as a result, it was demonstrated that a cost model based on the line classification and the correction factor was more reliable than the existing models. Furthermore, possibilities of using data from both the track measurement vehicle and from the maintenance information system, which are under development, have been investigated and, based on this investigation, a combined cost model using line classification, radius of curvature, gradient and worn-out rate, among other factors, will be proposed in the near future.

• Journal of the Korean GEO-environmental Society
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• v.19 no.2
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• pp.37-44
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• 2018

Ballasted track has been widely used due to its flexibility. However, the plastic deformation of ballasted track causes the evolution of track geometrical errors, and hence it requires continuous maintenance; increase in number of trains, weight, and speed expedites maintenance frequency and cost as well. Ballast stiffness is well-known as an indicator of design and maintenance. In this regard, this paper aims to suggest the method to measure ballast track stiffness using light-weight deflectometer (LWD) and thus verify its applicability as a maintenance measure. Preliminary field tests determined simple field testing protocol to measure track stiffness. The apparent ballast stiffness by LWD shows good corelation with TQI (Track Quality Index) and maintenance length. That is, as average of apparent stiffness increase, TQI and tamping length decrease exponentially. Therefore, apparent stiffness can be used as an index for ballast condition assessment.

• Journal of the Korean Society for Precision Engineering
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• v.27 no.5
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• pp.36-47
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• 2010

The Korean Railroad Research Institute (KRRI) has developed the rubber tired AGT system (Model: K-AGT) between 1999 and 2005. The K-AGT is a light rail transit system does not require a driver and generally operates on an elevated railroad for transporting passengers. Accidents caused by driverless vehicles can severely affect social confidence, safety and economy therefore, it is very important to minimize the occurrences of such faults, and to accurately perform detailed maintenance tasks and thoroughly investigate the cause of any repeated failures. This research develops the web-based Preventive Maintenance (PM) system for the KAGT train system. The framework of the PM system is based on performing a reliability analysis and a failure mode effects analyses (FMEA) procedure on all the sub-systems in the K-AGT system. Out of the devices that have a low reliability, the high failure ranked devices are included high in the list for performing the overall maintenance plans. Through registration of historical failure data, the reliability indexes can be updated. Such a process is repeated continuously and can achieve very accurate predictions for device operational life times and failure rates. Therefore, this research describes the development of the overall PM system consists of a reliability analysis module, a failure mode effect analysis module, and maintenance request module.

• Proceedings of the KSR Conference
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• 2011.10a
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• pp.2711-2717
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• 2011

This paper presents the classification scheme of the signal facilities on the railroad considering the construction costs and maintenance costs in a low population area. The construction costs of the new signal facility system can be compare with the costs of the present signal facilities as the classification scheme. The signal facilities on the railroad were classified as the railroad security regulations and then the scheme is considered through the LCC analysis. In order to test this research, the costs of signal facilities obtained from ones on TAEBACK railroad line. The costs categorized the construction costs, the labor cost and the maintenance costs can be effectively applied to the LCC analysis. The scheme is very useful to make a decision whether the new signal facilities on railroad in low population area is build or not in terms of the costs.

• Proceedings of the KIEE Conference
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• 2001.07b
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• pp.1245-1247
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• 2001

This paper discusses that the maintenance of the propulsion equipment in railway rolling stock. Condition monitoring of railway equipment is the need for integration of remote condition monitoring with maintenance management strategies. The paper outlines research leading to the design and development of a prototype control and monitoring system for propulsion equipment.

• Proceedings of the KSR Conference
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• 2005.05a
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• pp.574-580
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• 2005

Recently, the number of bridges and tunnels in railway is increasing due to the super high-speedy of train. Also, because of successively accidents of civil structures such as bridges and dams, the importance of maintenance become influential. The purpose of this study is to show the probabilistic life cycle cost analysis technique(PLCC) of the railroad bridge as pubic-infrastructures, and reasonably to indicate the economy in life cycle cost(LCC) through a case study. Rationally for life cycle cost analysis, the data gathered through many materials considered the uncertainty such as covariance. As a result, it is indicated that prestressed concrete bridge is pretty more cost-effective during life-cycle than preflex as well as steel box bridge. In future, if the construction of database and maintenance materials for railroad infrastructure is actualized, the life cycle cost analysis for railroad can be conducted easily and practically.