• Proceedings of the KSR Conference
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• 2003.05a
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• pp.762-767
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• 2003

The railroad is a means of large transportation which has many talents such as a safety and a regularity. That is a results from various confidential performance tests and evalutions of the system. The railroad system consist of various subsystems - vehicle, power spply, signal communications, track structures, operations, etc. Among them as an item of safety evaluation there is a measurement of wheel/rail force, so called a measurement of derailment coefficient. This is a very important item because a derailment of a train will bring about a big accident. Especially it is more important in high speed rail of which operation speed is over two times as fast as existing rail. In this paper, it is introduced to preprocess the wheelset for measuring wheel/rail force of Gwangiu EMU, such as to treat a measuring wheelset its finite element analysis, adhesion of strain gauges and static load test.

• Proceedings of the KSR Conference
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• 2006.11b
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• pp.1306-1311
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• 2006

Most of design parameters of Railway Structures are determined by the serviceability requirements, rather than the structural safety requirements. The serviceability requirements come from Ensuring of Running Safety and Ride Comfort of Train, Reduction of Track Maintenance Work Track-Bridge Interaction should be considered in the design of railway structures. In this study, a numerical method which precisely evaluate an axial force in rail and a rail expansion and contraction when turnout exist in succession on a CWR on a ballasted or on a ballastless track of bridge is developed. From the parameter studies using the developed method, additional stress of stock rail almost 25% is generated due to stock and lead rail interaction, even embankment not bridge. In case of ballasted track, additional stress of stock rail on bridge is very greater than on embankment, and therefore require detailed review in bridge design with turnout. Stresses of turnout rails on bridge are very sensitive according to the installed positions. In case of ballastless track, Stresses of turnout rails are similar as those of normal track

• Proceedings of the KSR Conference
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• 2004.10a
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• pp.283-289
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• 2004

Rail defects(Corrugation, shelling, etc) are occurred by the Rail with wheel contact stress. Rail grinding is maintaining of optimal rail profile to use special rail grinding machine to remove rail defect. The benefits of rail grinding enforcement, improve track safety, improve track steering and rail life, improve ride comfort and reduce noise, etc. Actually when rail grinding plan apply to field track, we should consider a lot of function before determination, such as grinding method, grinding pass number, removing metal volume, etc. because each track has various characteristics. Therefore it is important that the determination of rail grinding strategy for optimum and economic before enforcement.

• Journal of the Korean Society of Safety
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• v.38 no.1
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• pp.87-92
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• 2023

The number of unmanned light rail train operators is continuously increasing in Korea. In a failure event during an operation due to the nature of the unmanned operation, recovery is performed based on the remote control. However, if remote recovery is not feasible, safety personnel arrive at the train to resume the train operation. There are regulations on safety personnel and the suspension time of the train operation. However, there is currently no rule for safety personnel deployment. Currently, railway operating organizations operate in three scenarios: safety personnel on board trains, stationed at stations, and deployed at major stations. Four major factors influence the downtime for each emergency response scenario. However, these four influencing factors vary too much to predict results with simple calculations. In this study, four influencing factors were considered as random variables with high uncertainty. In addition, the Monte Carlo method was applied to each scenario for the safety personnel deployment to predict train service downtime. This study found a 17% difference in train service suspension by safety personnel deployment scenario. The results of this study can be used in setting service goals, such as standards for future safety personnel placement and frequency of service interruptions.

• Journal of the Korean Society of Safety
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• v.25 no.5
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• pp.54-61
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• 2010

The additional axial force of CWR(continuous welded rail) is occurred by structure-track interaction, in reverse, fixed supports of structure are applied the large load by that. Ratio of load which transferred on support through the bridge superstructure with one-side REJ by acceleration and braking load are stated in High-Speed Rail Design Criteria(2005). On the other hand the horizontal forces of support delivered to the load due to thermal loads has been no report about the criteria. Therefore, this study was performed the review of the reaction and displacement on support by structure-track interaction in a special bridge(composite brdiges, 45+55+55+45=200m) with REJ acting on the temperature load. As a result, because fixed support of a special bridge or a continuous bridge with REJ under the temperature load which is constant load has been acted the large lateral load by structure-track interaction, when determining the fixed bearing capacity of structure should be reflected in the results to secure the safety of structures was confirmed.

• Proceedings of the KSR Conference
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• 2009.05a
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• pp.546-547
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• 2009

To ensure stability of continuous welded rail in extremely hot weather is important to the railway industry's goal of operational safety and maintenance. Rail temperature has direct influence on track buckling. According to climate condition, distribution of rail temperature is different. In this study, the fluctuation of rail temperature were investigated under the domestic climate condition (air temperature, humidity, insolation, etc)

• Proceedings of the KIEE Conference
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• 2007.10c
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• pp.238-240
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• 2007

This paper present adaptation method of rail potential test to verify DC railway system's performance and safety. For protection of person and utility caused by rail potential rise, international standard to limit rail potential rise is made and rail potential is tested at the time of plan and construction of DC railway system in foreign country. So, we need rail potential test at the opening time and prepare a continuous monitoring technique of rail potential and a limitation method of rail potential rise. For these, we describe cause of rail potential rise, international standard about rail potential, protection principle, an example of calculation and measurement, and adaptation method for performance test.

• Proceedings of the Korean Geotechical Society Conference
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• 2003.06a
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• pp.13-22
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• 2003

Train speed and infiltration of rainfall causes railway embankment to be unstable and may result in failure. Therefore, the variation in the safety factor of railway embankment should be analyzed as the function of rainfall intensity, rainfall duration, and train speed and the study is accomplished using numerical analysis program. Based on unsaturated soil engineering, the variables in the shear strength function and permeability function are also defined and used for the numerical model for evaluation of railway embankments under rainfall. As a result of the study, in order to secure the safety of train under rainfall, the variation in the safety factor of railway embankment is predicted as the function of rainfall intensity, duration time and the train load as a function of train speed. It is possible to ensure the safety of train under rainfall. Thereafter, the feasibility of the rail-transport operation control with engineering basis was established.

• Journal of the Korean Society of Safety
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• v.32 no.4
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• pp.28-33
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• 2017

A sharp curved ballasted track on earthwork that was connected with a direct fixation slab track on steel box railway bridges have been deformed and damaged despite the frequently maintenance by a restoring force of sharp curved rail and track-bridge interaction forces such as axial forces and longitudinal displacement of continuous welded rail(CWR) owing to their structural characteristics, calling for alternatives to improve the structural safety and track irregularity. In this study, the authors aim to prove a cause of deformation for the sharp curved ballasted tracks to enhance the structural safety and track irregularity of ballasted track in service. A track-bridge interaction analysis and a finite-element method analysis for the sharp curved ballasted track were performed to consider the axial force and longitudinal displacement of CWR, the temperature and the effect of restoring force of sharp curved rail. From the results, the deformation of the sharp curved ballasted track with adjusted sleeper spacing from 833mm to 590mm were significantly reduced.

• International Journal of Reliability and Applications
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• v.4 no.4
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• pp.183-190
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• 2003

Rail breaks and derailments can cause a huge loss to rail players due to loss of service, revenue, property or even life. Maintenance has huge impact on reliability and safety of railroads. It is important to identify factors behind rail degradation and their risks associated with rail breaks and derailments. Development of mathematical models is essential for prediction and prevention of risks due to rail and wheel set damages, rail breaks and derailments. This paper addresses identification of hazard modes, estimation of probability of those hazards under operating, curve and environmental condition, probability of detection of potential hazards before happening and severity of those hazards for informed strategic decisions. Emphasis is put on optimal maintenance and operational decisions. Real life data is used for illustration.