• Journal of the Korea institute for structural maintenance and inspection
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• v.16 no.6
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• pp.143-154
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• 2012

The wireless low-floored tram is an innovative transportation system which is environment-friendly and highly energy-efficient. In addition, the system has various advantages such as low construction cost, improvement of urban landscape, revitalization of surrounding commercial area, elevated convenience for passengers, etc. Therefore, more than ten local governments have proposed tram construction projects in Korea. Accordingly, many research and development projects are ongoing funded by government including the developments of tram vehicle, tram trackway, signal system, etc. The embedded rail system are commonly used in order to provide leveled roadway surface in urban area. It is effective to reduce the noise and vibration, caused at the interface between the wheel and track, to minimize the construction period, and to lower the maintenance cost. This paper investigated the design and construction processes for tram trackway and figured out the constructability for the test track with embedded rail system for the first time in Korea. The performance to reduce the noise and vibration were quantitatively measured in the test track with embedded rail system. In addition, the results were compared to the ones for track with conventional rail system.

• 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.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2004.05a
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• pp.159-163
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• 2004

The KNR(Korean National Railroad) has a speed limit regulation(130km/h) for the train passing the turnout to guarantee a safety. Since that speed is set as below the maximum commercial speed(140km/h), it has been regarded as a major factor to obstacle the total efficiency. The crossing rail part of the turnout system is formed into a antisymmetric, furthermore, there are several discontinuous part. Thus, measuring the strain signals of this part is impossible actually and it must be in the most difficult work related the turnout research. In this research, the program that can anticipate the signals at the various conditions with considering its own shape was developed and the preciousness of its results had been examined by comparing analyzed and measured ones at the other parts. The simulation was performed with varying the factors such as train speed and contact depth. As a results, it was proved that the regulation was not useless and very important guide at least up to now.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2000.06a
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• pp.900-910
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• 2000

This study have been performed to investigate the dynamic behavior of the Korean High Speed Train(KHST) during the conceptual design process. This study gets a focus on the analysis of the rigid model, for which the yaw damper layout is modified in a nonlinear limit cycle analysis. In this study, influences of the system parameters such as stiffness of suspension and connection elements as well as damping coefficients were studied and an optimized parameter set is achieved. Throughout the dynamic calculation of KHST on the straight and the curved track, vibration accelerations in car body, ride comforts and wheel rail forces are investigated. Finally the vibration characteristics from rigid car body are compared with those due to the influence of elastic car body.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 1997.04a
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• pp.241-246
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• 1997

Corrugation of railway track can be caused by the various dynamic behaviors of traveling wheels and track. In this paper, the coupled vibrations of traveling wheel and railway track are analyzed as the cause of corrugations. To analyze the coupled vibration, the track supported by the sleepers and the traveling wheels are identified to the elastically supported infinite beam and the spring-mass system which runs at constant speed. The Hertzian contact spring is considered between the infinite beam and spring-mass system. The dynamic responses of elastically supported infinite beam and spring-mass system are calculated. The cause and development of rail corrugation are discussed in the view point of contact force fluctuation affected by the elastic supports and the corrugated surface profile on the track. By the obtained results, the possibilities of resonance are checked between the excitation by the corrugated surface profile and the natural frequency of contact spring-mass system. It may be thought to a development of railway corrugation.

• Journal of the Korean Society for Railway
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• v.14 no.3
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• pp.211-215
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• 2011

Generally, sound power is one of the most significant factors to predict and assess noise from sound sources. However, many researchers developed indirect methods to calculate the sound power with noise level because it is impossible to measure sound power directly while a train is running. In this paper, we propose a method to estimate sound power generated due to wheel/rail interaction and propulsive equipment from the measurement of noise emitted from rolling stocks and verify the estimation method by comparing with the other sound power estimation formula. We also analyze the sound power of rolling stocks which are operating in domestic lines such as EMU, Mukoonghwa, KTX using the method proposed in this paper.

• Journal of the Korean Society for Railway
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• v.20 no.4
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• pp.440-447
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• 2017

Spectrum level for the acoustic roughness of wheels and rail surface should be periodically maintained under the limitation of ISO to reduce rolling noise of railway vehicles. Thus, in maintaining railway track, displacement sensor-based measuring devices are broadly used to measure the surface roughness and to perform spectral analysis. However, these measuring devices cause unexpected measuring errors since the displacement sensors are fixed at moving platforms and the main frame produces pitching motion during measurement. To increase the accuracy of the measured values, this paper has investigated the effects of design variables such as wheel base, additional wheels, and elastic deformation of wheels on the surface roughness and acoustic roughness spectrum.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.26 no.2D
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• pp.299-309
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• 2006

Railway noise and vibration has been recognized as major problems with the speed-up of rolling stock. As a kind of solution to these problems, the decrease of stiffness of track pad have been tried. However, in this case, overturning of rail due to lateral force should be considered because it can have effect on the safety of running train. Therefore, above two things - decrease of stiffness of track pad and overturning of rail due to lateral force - should be considered simultaneously for the appropriate determination of spring coefficient of track pad. With this viewpoint, minimum spring coefficient of track pad is estimated through the comparison between the theoretical relationship about the overturning of rail and 3-dimensional FE analysis result. Two kinds of Lateral force and wheel load are used as input loads. Extracted values from the conventional estimation formula and the Shinkansen design loads are used. It is found that the overturning of rail changes corresponding to the change of the stiffness of track pad and the ratio of lateral force to wheel load. Moreover, it is found that the analysis model can have influence on the results. Through these procedure, minimum spring coefficient of track pad is estimated.

• Proceedings of the KSR Conference
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• 2011.10a
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• pp.2464-2472
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• 2011

Train runs on high speed and the concrete track is constructed. Rail fastening device needs to reduce elasticity, transferred load, noise, and vibration etc. Consequently, low elastic pad has a great impact of the durability and stability of the track. In this study, discussed in previous studies, static numerical analysis and real scale repeated loading test, followed by dynamic response analysis were implemented. The most distinctive characteristics of the model proposed is to simulate the real wheel behavior on rail. And the main analysis object is to evaluate and compare the deformation characteristics of the transition track while load reduction effect of transfer on roadbed assessed by various low elastic pad.

• Journal of KSNVE
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• v.7 no.6
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• pp.953-958
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• 1997

Corrugation of railway track can be caused by the various dynamic behaviors of traveling wheels and track. In this paper, the coupled vibrations of traveling wheel and railway track are analyzed as the cause of corrugations. To analyze the coupled vibration, the track supported by the sleepers and the traveling wheels are identified to the elastically supported infinite beam and the spring-mass system which runs at constant speed. The Hertzian contact spring is considered between the infinite beam and spring-mass system are calculated. The cause and development of rail corrugation are discussed in the view point of contact force fluctuation affected by the elastic supports and the corrugated surface profile on the track. By the obtained results, the possibilities of resonance are checked between the excitation by the corrugated surface profile and the natural frequency of contact spring-mass system. It may be thought to a development of railway corrugation.