• Structural Engineering and Mechanics
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• v.77 no.2
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• pp.231-243
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• 2021

In this paper, a dynamic response mapping model of the wheel-rail system is established by using the support vector regression (SVR) method, and the hierarchical safety thresholds of the subgrade void are proposed based on the reliability theory. Firstly, the vehicle-track coupling dynamic model considering the subgrade void is constructed. Secondly, the subgrade void area, the subgrade compaction index K30 and the fastener stiffness are selected as random variables, and the mapping model between these three random parameters and the dynamic response of the wheel-rail system is built by using the orthogonal test and the SVR. The sensitivity analysis is carried out by the range analysis method. Finally, the hierarchical safety thresholds for the subgrade void are proposed. The results show that the subgrade void has the most significant influence on the carbody vertical acceleration, the rail vertical displacement, the vertical displacement and the slab tensile stress. From the range analysis, the subgrade void area has the largest effect on the dynamic response of the wheel-rail system, followed by the fastener stiffness and the subgrade compaction index K30. The recommended safety thresholds for the subgrade void of level I, II and III are 4.01㎡, 6.81㎡ and 9.79㎡, respectively.

• Proceedings of the KSR Conference
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• 2007.11a
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• pp.953-958
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• 2007

To assess the derailment safety of the Samaeul Train, We developed a fleet analysis model and carried out sensitivity analysis of the variables related to derailment factors with ADAMS/Rail computing analysis method. Depending on the variation of the running speed in curve section, derailment coefficient and wheel load reduction rate are high at right side wheels in slow running speed section and low at left side wheel in high running speed. According to decreasing the radius of curve, derailment coefficient and wheel load decreasing rate are increased. Derailment coefficient is proportional to transition curve length and wheel load decreasing rate is constant. Cant value rising causes wheel load deduction rate rising.

• 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.

• Proceedings of the KSR Conference
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• 2009.05b
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• pp.351-355
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• 2009

There are two types of controller between railway and train. those are the Continuous Message Controller and the Intermittent Message Controller using for KHSR. The conventional Intermittent Message Controller board used a variable resister for setting the phase, but the variable resister affected some environmental facts, such as temperature, humidity, and vibration, etc. And It is requirement of reduction message processing time for speed-up operation in Next-Generation High-Speed Rail. This study suggests how to solve the problem described above. Using FPGA is quite profitable. It's easy to use and maintain, flexible with the New algorithm to fix up the problem.

• Journal of the Korean Society for Railway
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• v.19 no.6
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• pp.736-743
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• 2016

In accordance with the trend of higher speed and automation, the Train Control System is building on the technology of control methods using radio in the technology of exchanging information by wire, toward a wireless communication method that will be applied using LTE-R radio communication technology with $4^{th}$ generation LTE mobile communication a $2^{nd}$ generation GSM-R. Therefore, a standard specification suitable for the Korea Radio based Train Control System-2(below KRTCS-2) for the 350km/h class using wireless communication is created; a prototype based on the standard specification is installed on a high-speed train and is installed on a test section(Ik san-Jeong eup) on the Honam high speed line to ensure the reliability and safety of the standard specifications, which are verified through various performance tests. In the future, the standard specification that has been established as a national railway standard, and the standard specifications will be commercialized by applying the train control system to conventional and High speed railway lines.

• Transactions of the Korean Society for Noise and Vibration Engineering
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• v.20 no.8
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• pp.703-709
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• 2010

An analysis tool for predicting transmission loss in high speed trains based on combined use of the statistical energy analysis and the finite element methods has been proposed. The analysis utilizes a commercially available numerical solver VA ONE with imbedded NASTRAN module. The proposed analysis tool is first verified by comparing numerically predicted transmission loss of a light rail transport(LRT) structure with experimental results. The comparison shows that the numerically predicted transmission loss is similar to the experimental data. The analysis tool is then applied to the prediction of transmission loss in the high speed train(HST) currently under development. Various sub-structures such as the floor, side panel and ceiling have been numerically analyzed to predict their transmission losses. The results obtained here can be used as input data for predicting the interior noise level of the HST at design stage.

• Journal of Korean Society of Industrial and Systems Engineering
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• v.25 no.4
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• pp.22-31
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• 2002

A high-speed rail system represents a typical example of large-scale multi-disciplinary systems, consisting of subsystems such as train, electrical hardware, electronics, control, information, communication, civil technology etc. The system design and acquisition data of the large-scale system must be the subject under strict configuration control and management. Not only the requirements of the large-scale system dictate the contracts with the suppliers but also become the basis for the development process, project execution, system integration, and testing. The requirements database provide the system design specification of all development activities. Using the RDD-100, a systems engineering tool, the Korea next-generation high-speed rail program can establish requirements traceability and development process management in performing the enabling train technology development projects. This paper presents the results from a computer-aided systems engineering application to the Korea next-generation high-speed railway project. Especially, the focus of the study was on requirement management and PBS(Product Breakdown Structure) management.

• Smart Structures and Systems
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• v.21 no.5
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• pp.653-668
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• 2018

This work proposes and investigates re-centering negative stiffness dampers (NSDs) for vibration suppression in high-speed trains. The merit of the negative stiffness feature is demonstrated by active controllers on a high-speed train. This merit inspires the replacement of active controllers with re-centering NSDs, which are more reliable and robust than active controllers. The proposed damper design consists of a passive magnetic negative stiffness spring and a semi-active positioning shaft for re-centering function. The former produces negative stiffness control forces, and the latter prevents the amplification of quasi-static spring deflection. Numerical investigations verify that the proposed re-centering NSD can improve ride comfort significantly without amplifying spring deflection.

• Proceedings of the Korea Concrete Institute Conference
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• 1998.04b
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• pp.755-760
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• 1998

In the present, we have developed high strength concrete for the sleepers of high speed rail and verified its applicability by in-situ applications. Concrete for sleepers is manufactured by steam curing at low temperature(below 55$^{\circ}C$), and should be finished its manufacturing process such as placing, curing, demolding and prestressing in 24 hours. The sleepers need its compressive strength above 350kg/$\textrm{cm}^2$ in 15 hours, air-entrainment for durability and nominal design strength of 600kg/$\textrm{cm}^2$, considering its quality variation at factory. We performed the optimum mix design of concrete and verified the rightness of the use of TYPE III cement. Finally, we have confirmed the manufactured sleepers satisfy the required material properties through in-situ application.

• Transactions of the Korean Society for Noise and Vibration Engineering
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• v.11 no.8
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• pp.349-356
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• 2001

The dynamic behavior of high speed train is very Important because the railway should be safe and Is satisfied tilth the rode comfort of passengers. The train is composed of many suspension components. such as 1st springs, 1st dampers, 2nd springs and 2nd dampers, that have an influence on the dynamic characteristics of high speed train. Also, the wheel/rail shapes, the track conditions and geometry and many environmental factors, such as rain, snow and wind. affect the dynamic behavior of high speed train. This paper reviews the effect of wind and track conditions on the dynamic behavior of high speed train. The VAMPIRE program Is used for this simulation. The result of simulation shows that the high speed train should not be operated when the wind velocity is beyond 34.5 m/sec.