• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2013.10a
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• pp.564-569
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• 2013

An accurate railway environmental noise prediction model is required to make the proper solution of the railway noise problems. In this paper, an engineering model for predicting the noise of conventional passenger cars is presented considering the acoustic source strength in octave-band frequencies and the propagation over grounds with varying surface properties. Since the formation of a train can be variable, the source strength of each locomotive and passenger car was estimated by measuring the pass-by noise and analysing the wheel-rail rolling noise. Some validation cases show on the average small differences between the predictions of the present model and the measurement results.

• Transactions of the Korean Society for Noise and Vibration Engineering
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• v.26 no.6_spc
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• pp.674-679
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• 2016

According to the conventional studies on the noise and cardiovascular effect, railway noise is better associated with hypertension and adverse cardiovascular events than road traffic noise. But the underlying mechanisms remain unclear. We investigated the hypothesis that exposure to acute railway noise would the unfavorable effect of cardiovascular and autonomic system in healthy young subjects. Using a randomized, sham-controlled cross-over design, ten subjects were assigned to receive either an exposure to high speed train noise (84 dB) for 30 minutes or a control condition (non noise), separated by two days. Blood pressure, heart rate, augmentation index and heart rate variability as indices of cardiovascular and autonomic system function were measured at baseline, during, and recovery from two trials. The results show that exposure to acute railway noise significantly increased diastolic blood pressure and augmentation index, which may cause of adverse cardiovascular effects.

• Proceedings of the KSME Conference
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• 2001.11a
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• pp.629-634
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• 2001

The construction of the elevated railway has led to concerns about the noise from trains, particularly as tracks often pass close to residential dwellings. One specific issue relates to the noise from trains on bridges. The wayside noise for the train was measured to get the basic data that can be used to prepare count measures for solving environmental noise problems. Noise levels were measured simultaneously at three points in various distances from the railroad and at four points classified by floor. In this paper we measure the wayside noise in elevated railway and noise of normal operation compare with operating under train engine idling condition and investigate effect of nearby-building induced by train operation.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2013.04a
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• pp.644-647
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• 2013

The important source of noise from railways is rolling noise caused by wheel and rail vibrations induced by acoustic roughness at the wheel-rail contact. The main contributors for rolling noise are the sleepers, rail and wheels. In order to analyze and predict rolling noise, it is necessary to understand the vibrating behaviors of railway tracks, as well as the wheels. In the present paper, theoretical modelings of the railway track are reviewed in terms of the rolling noise, and they are applied for the three representative types of domestic railway tracks operated: the conventional ballasted track, KTX ballasted track and KTX concrete track. The characteristics of waves propagating along rails were investigated and compared between the tracks. The tracks were modeled as discretely supported Timoshenko beams and compared in terms of the averaged squared amplitude of velocity which is directly related to the sound radiation from the rails.

• Proceedings of the KSR Conference
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• 2011.10a
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• pp.2852-2859
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• 2011

Planning and construction of railway for high speed trains up to 400 km/h are recently driven in Korea. High speed train is one of the environment-friendly fastest mass transportation means but its noise generated by rolling, traction and aerodynamic mechanism can cause public complaints of residents nearby railways. To cost-effectively prevent the troublesome noise in a railway planning stage, the rational railway noise prediction method considering the characteristics of trains as well as railway structures should be required but it is difficult to find an authentic method for Korean high speed trains such as KTX and KTX-II. In this study, recent railway noise prediction methods developed by EU countries are introduced and discussed for consulting before setting the framework of our own railway noise prediction model emitted by Korean high speed trains over 250 km/h. Especially, the new Schall 03 model (2006) developed by Germany and IMAGINE model (2007) suggested by an EU framework research project are intensively reviewed. In addition, research items required for the development of our own model are suggested.

• Transactions of the Korean Society for Noise and Vibration Engineering
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• v.21 no.5
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• pp.400-407
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• 2011

The suggested method of previous Son's study dichotomized subjective response data to modeling noise exposure-response. The method used maximum liklihood estimation instead of least square estimation and the noise exposure-response curve of the study was logistic regression analysis result. The method was originated to modeling community response rate such as %HA or %A. It can be useful when the subjective response was investigated based on predicted noise level. It is difficult to measure the single source emitting noise such as railway because various traffic noise sources combined in our life. The suggested method was adopted to model in this study and railway noise-exposure response curves were modeled because the noise level of this area was predicted data. The data of this study was used by previous Ko's paper but he dealt the area as combined noise area and divided the data by dominant noise source. But this study used all data of this area because the annoyance response to railway noise was higher than other noise according to the result of correlation analysis. The trend of the %HA and %A prediction model to train noise of this study is almost same as the model based on measured noise of previous Lim's study although the investigated areas and methods were different.

• Journal of the Korean Society for Railway
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• v.6 no.3
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• pp.209-214
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• 2003

When a rail vehicle transverses tight curves, it often emits an intense, high-pitched squeal. This squeal has always been noticed as one of the most disturbing noise sources of railway systems. At present, we cannot predict squeal noise that is influenced by a large number of dependent parameters. In this study, we performed structural analysis to find out the frequency of the wheel and measured squeal noise at Seoul subway. We also tested reduction effectiveness of squeal noise through rail lubricator.

• Proceedings of the KSR Conference
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• 2003.05a
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• pp.627-632
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• 2003

Squeal noise is generated by railway vehicles transversing tight curves. This squeal has always been noticed as one of the most disturbing noise sourecs of railway systems. At present we cannot predicted squeal noise that is influenced by a large number of dependent parameters. But the application of wheel damping and rail lubrication have successfully reduced wheel squeal. In this study, we measured squeal noise to find out the reduction effectiveness of noise through rail lubricator.

• Transactions of the Korean Society for Noise and Vibration Engineering
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• v.20 no.2
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• pp.172-178
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• 2010

The multiple regression analysis and path analysis in each dominant area of noise source are conducted to analyze the relationship between dependent variables like annoyance and independent ones such as noise and non-noise factors. The multiple regression analysis shows that impact of noise factors is the highest to annoyance in dominant areas of road traffic and railway noise. Meanwhile, impact of non-noise factors such as sensitivity and satisfaction of environment on annoyance is also high in these areas. The path analysis result for multivariate analysis between various independent and dependent variables is similar to that of the multiple regression analysis. However, noise factor is the greatest factor influent on annoyance in the dominant areas of the combined noise, and relationship between annoyance and sensitivity is the highest in combined area exposed to road traffic noise and railway noise.

• Journal of Environmental Impact Assessment
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• v.20 no.4
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• pp.443-453
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• 2011

The purpose of present study is to develop a noise map around Korean Train Express (KTX) line. It is also to evaluate the high speed railway noise influence in neighboring areas around KTX. In order to develop the noise map, noise source modeling and 3-D noise radiation simulation have been performed by means of SoundPLAN program. The result of the noise map has been verified in comparison with the measured noise level. Noise measurements have been performed at 15 locations around KTX line. At each locations, 6 microphones were located 1.5m and 3m above the ground at each of 25m, 50m and 75 m distances from a center of the KTX track. The noise map showed clearly the high speed railway noise influence in neighboring areas around KTX line. The present study has also showed the noise could be reduced by using noise barriers constructed at severely noise-exposed locations.