• Journal of the Korean Society for Railway
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• v.20 no.3
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• pp.320-328
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• 2017

In order to analyze the influence on derailment safety according to the aging of primary rubber springs widely applied to railway vehicles, characteristic tests were carried out on aged primary rubber spring samples. To analyze the effect of primary rubber spring aging on derailment safety, a vehicle dynamic analysis was carried out. The results of the vertical characteristics test for the rubber spring specimens with 17 years of service life revealed that the displacement restoration function was degraded due to rubber aging and the spring stiffness significantly increased. The results of the running dynamic analysis simulating the twist track running in accordance with the EN14363 standard, compared with the normal vehicle model (Case 1), showed that the derailment coefficient and the wheel unloading of the vehicle model (Case 2) using the aging primary spring characteristic increased, and the derailment safety was degraded. IN particular, it was found that the derailment safety due to the reduction of the wheel load is weak in the transient section where a steep slope change occurs.

• Proceedings of the KSR Conference
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• 2007.05a
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• pp.514-522
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• 2007

Railway System has been developed by applying the advanced technology so that it reduces accident of hardware failure. But human error has been founded as important cause in railway accidents and safety. Medical condition is one of railway accident causes. Failure to recognize potentially incapacitating medical conditions can have serious safety consequences for railroad employees, the railroads and the public[1]. In order to find potential danger, we collect domestic/ foreign case for the medical examination and analyse characteristic/difference. The purpose of this study is to suggest information of employees' medical examination through comparing the current medical standard in railway industries.

• Journal of Electrical Engineering and Technology
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• v.1 no.4
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• pp.513-519
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• 2006

As a very important part in development of the protocol, verifications for developed protocol specification are complementary techniques that are used to increase the level of confidence in the system functions by their specifications. Using the informal method for specifying the protocol, some ambiguity may be contained therein. This indwelling ambiguity in control systems can cause the occurrence of accidents, especially in the case of safety-critical systems. To clear the vagueness contained in the designed protocol, we use the LTS (Labeled Transition System) model to design the protocol for railway signaling. And then, we verify the safety and the liveness properties formally through the model checking method. The modal ${\mu}$-calculus, which is an expressive method of temporal logic, has been applied to the model checking method. We verify the safety and liveness properties of Korean standard protocol for railway signaling systems. To perform automatic verification of the safety and liveness properties of the designed protocol, a communication verification tool is implemented. The developed tools are implemented by C++ language under Windows XP. It is expected to increase the safety and reliability of communication protocol for signaling systems by using the developed communication verification tool.

• Proceedings of the KSR Conference
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• 2002.10a
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• pp.281-289
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• 2002

This paper is described for the flame behaviors in light railway cabin by numerical simulation code, which can be interpreted the design parameters in terms of suppression the fire propagation and excavation the passengers safely. The results shows that the flame intensity(fire temperature, smoke density) depends on the firing points in cabin and propagates rapidly whole cabin space rather than modern subway cabin due to smaller inner space. The data will be used to how can be get the safety case, which is described on the operating principles for all facilities and logistics against to the light railway firing accidents.

• Geomechanics and Engineering
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• v.28 no.2
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• pp.145-155
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• 2022

Safety is a most important parameters in underground railway transportation; Also stability of underground tunnel is very important in tunneling engineering. Design of a reliable support system requires an evaluation of both ground demand and support capacity. Iran's traditional railway tunnels are mainly supported with masonry structures or unsupported in high quality rock masses. A decrease in rock mass quality due to changes in groundwater regime creep and fatigue in rock and similar phenomena causes tunnel safety to decrease during time. The case study is an old tunnel in Iran, called "Keshvar"; it is more than 50 years old railway organization. In operating this Tunnel, until the several problems came up based on stability and leaking water. The goal of study is evaluation of the various reinforcement systems for supporting of the tunnel. The optimal selection of the reinforcement system is examined using TOPSIS Fuzzy method in light of the looming and available uncertainties. Several factors such as; the tunnel span, maintenance, drainage, sealing, ventilation, cost and safety were based to choose the method and system of designing. Therefore, by identifying these parameters, an optimal reinforcement system was selected and introduced. Based on optimization system for analysis, it is revealed that the systematic rock bolts and shotcrete protection had a most appropriate result for these kind of tunnel in Iran.

• Journal of the Korean Society of Safety
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• v.30 no.5
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• pp.114-122
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• 2015

FMEA and FTA have been widely applied to the safety studies for railway systems respectively. But it would be more effective to use these two methods at a same time because these are complementary. This article suggests a FMEA-FTA combined analysis technique to evaluate the risk for railway systems. A FMEA-FTA combined risk evaluation model and process are proposed and a case study is dealt with for PBU(Pneumatic Breaking Unit), a major subsystem of a railway vehicle.

• Journal of the Korea Safety Management & Science
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• v.15 no.1
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• pp.51-60
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• 2013

As the human demand or desire on brand new systems otherwise equipped with new functions grows drastically, so does the complexity of the systems. With this trend, the systems are becoming bigger in scale and at the same time the safety requirements are more stringent in the development. Typical systems examples in such a situation may include high-speed railway systems, aero and space systems, marine systems, etc. Failure of those systems can cause serious damages on both the human being and wealth with social infrastructure. As such, it is quite necessary to ensure that the safety requirements be satisfied in the system development. To achieve this need, there could be a lot of solutions to take. In this paper, regarding safety, a special attention is given to the verification phase process, which is one of the intermediate phases of whole systems development process. More specifically, the ultimate concern is placed on how to carry out the design verification while ensuring the safety requirements. To do so, some improvements in the verification phase were proposed first. Then, the outcomes were combined with the systems safety process by generating an integrated process model to reach the goal. As a case study, application to a railway system was discussed, where strict safety requirements are usually necessary. It would be expected that the potential likelihood of failure with rail systems could be reduced if the results obtained are used effectively with some enhancement from further study.

• Journal of the Korean Society for Railway
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• v.20 no.3
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• pp.349-355
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• 2017

Failures of railway systems can result in train delays or accidents, and therefore high reliability is required to ensure safety of railway systems. To improve reliability, railway systems are designed with redundant systems so that the standby system will continue to function normally even if the primary system fails. Generally, overall system reliability can be evaluated by the reliabilities of the parts of the whole system and the reliability of the redundant system considering common failures in case of each system is not conform physical, functional and process independent. In this study, the reliability of the hot-standby sparing system is analyzed the independent systems and dependent systems with common failures. The reliability for the standby system can be effectively analysed using Markov models, which can model the redundant configuration and the state transition.

• Journal of the Korean Society for Railway
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• v.6 no.1
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• pp.1-9
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• 2003

This article proposes an integrated systems engineering and safety analysis model for safety-critical systems development. A methodology in system design for safety is considered during the early phase of the development life cycle of systems engineering process. The evolution of the design automation technology has enabled engineers to perform the model-based systems engineering. A Computer-Aided Systems Engineering(CASE) tool, CORE, is utilized to integrate the systems engineering model with a system safety analysis model. The results of the functional analysis phase can drive the analysis of the system safety. An example of Communications-Based Train Control(CBTC) system for an Automated Guided Transit(AGT) system demonstrated an application of the integrated model.

• International Journal of Safety
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• v.10 no.1
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• pp.36-40
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• 2011

Personnel maintaining or repairing the railway tracks or signaling facilities around tracks may experience the sensory disorder when doing maintenance works at the trackside of railway for long time. In this case personnel maintaining at the trackside may collide with the train since they cannot recognize the approach of motor-car 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. In order to prevent such motor-car accidents that may occur because railway track workers are unable to recognize the approaching train, the safety alarm equipment is developed to make the approaching motor-car send radio signals and bidirectional detection mechanism between approaching train and trackside personnel. It shows the possibility of utilization in various forms of safety equipment for workers only to the safety helmet to be worn by the maintenance workers while using the configuration of transmitting/receiving sides. In the paper it is represented new alarm equipment, which is the bone-anchored speaker-based safety helmet to be worn by the maintenance workers.