• Journal of the Korean Society for Railway
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• v.19 no.4
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• pp.547-554
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• 2016

This study considered how to estimate the deterioration rate of the track quality index, which represents track geometric irregularity. Most existing studies have used a simple linear regression and regarded the slope of the regression equation as the progress rate. In this paper, we present a Bayesian approach to estimate the track irregularity progress. This Bayesian approach has many advantages, among which the biggest is that it can formally include the prior distribution of parameters which can be derived from historic data or from expert experiences; then, the rate can be expressed as a probability distribution. We investigated the possibility of applying the Bayesian method to the estimation of the deterioration rate by comparing our bayesian approach to the conventional linear regression approach.

• Proceedings of the KSR Conference
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• 2008.11b
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• pp.1024-1028
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• 2008

The ballast, one of track components, plays an essential role as intermedium in transmitting train load to subgrade safely, and the deterioration of ballast directly effects the growth of track irregularity. In this study, we determined the main factor of ballast deterioration was miniature of ballast gravel caused MTT(Multiple Tie Tamper) works and accumulated traffic loads. To estimate the deterioration characteristics of ballast, we carried out field test through track construction for test and the model test simulating the actual operation environment, have done a comparative analysis with the sample's result(crushing rate) of high-speed railroad running actually.

• Proceedings of the KSR Conference
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• 2011.10a
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• pp.1802-1809
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• 2011

A distribution method of limited budget for rail line facility improvement is to use investment priorities of rail line segments based on their deterioration. In this paper we present an evaluation method of rail line segment deterioration which can be used to distribute limited budget. Rail line facilities include rail track, crossing, road bed, bridge, tunnel. These facilities deterioration and line shape can affect line segment deterioration. Deterioration evaluation method we present is a weighted sum of each component deterioration scores. The component weight can be obtained from experts using analytic hierarchy process.

• Journal of the Korean Society for Railway
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• v.11 no.4
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• pp.384-389
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• 2008

The ballast, one of track components, plays an essential role as intermedium in transmitting train load to subgrade safely, and the deterioration of ballast directly effects the growth of track irregularity. In this study, we determined the main factor of ballast deterioration was miniature of ballast gravel caused MTT (Multiple Tie Tamper) works and accumulated traffic loads. To estimate the deterioration characteristics of ballast, we carried out field test (Chap.2) through track construction for test and the model test (Chap.3) simulating the actual operation environment, have done a comparative analysis with the sample's result (crushing rate) of high-speed railroad running actually.

• Proceedings of the KSR Conference
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• 2007.11a
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• pp.1126-1131
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• 2007

In 1st Phase Kyeong-Bu High-Speed Line, to lessen the impact in the transition zone between concrete slab track(in tunnel) and ballasted track(on embankment), the ballast bonding method has been adopted. However, in this area, in the beginning of the operation, unsupported sleepers are found, and the track deterioration and damage of concrete sleepers have occurred. In this paper, the status and causes of unsupported sleepers are discussed and several repair measures are proposed.

• The Journal of the Convergence on Culture Technology
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• v.5 no.4
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• pp.387-394
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• 2019

In this study, in order to evaluate the damage and deterioration of the track components of sleeper floating track (STEDEF), the field samples(specimens) were taken from the serviced line over 20 years old, and the track components were visually inspected, and investigated by laboratory tests and finite element analysis. As a result of visual inspection, the damage of the rail pad and fastener was slight, but the rubber boot was worn and torn at the edges of bottom. The resilience pads were clearly examined for thickness reduction and fatigue hardening layer. As a result of spring stiffness test of rail pad and resilience pad, the deterioration of rail pad was insignificant, but the deterioration of resilience pad exceeded design standard value. Therefore resilience pad was directly affected by train passing tonnage. As a result of comparing the deterioration state of the field sample and the numerical analysis result, the stress and displacement concentration position of the finite element model and the damage position of the field sample were coincident.

• Journal of the Korean Society for Railway
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• v.17 no.2
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• pp.106-113
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• 2014

In this study, a practical evaluation technique to detect the deterioration of railroad lines by means of train performance and track geometry measures is suggested. A train that has a specific performance and is running the straight line can make minimum travel time (ideal time). But the actual travel time will be increased by the track geometry and various speed limitations. By comparing these travel times, we can easily define the degree of line deterioration. This method does not require complex vehicle performance measures and/or specifications that exceed those of typical Train Performance Simulations (TPS). For this reason, ease of use is ensured and the results are similar to those obtained by running a TPS for practical evaluations.

• Proceedings of the KSR Conference
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• 2005.11a
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• pp.370-375
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• 2005

Floating sleepers in a ballasted track increase both track deterioration and track irregularities. Consequently, a considerable maintenance work is required and maintenance cycle is shortened due to the floating sleepers. This paper quantifies the degrees of void between the floating sleepers and a ballast bed. In the future, the influence of floating sleepers on the track will be investigated by an analytical method using a dynamic model.

• Journal of the Korean Society for Railway
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• v.2 no.3
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• pp.61-69
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• 1999

The durability of ballast plays an important role in track behaviour. To estimate the deterioration characteristics of ballast, several tests have been carried out by several scholars. The deterioration characteristics is very important factor in the behaviour of track and its life. In this paper, abrasion/breakage characteristics of ballast is studied to see the effect of physical ballast characteristics on ballast life. To reveal breakage characteristics of ballast, the ballast box test and the MTT field test were carried out. The breakage characteristics studied in this paper is applied to the ballast life prediction in various conditions, such as LA abrasion, annual tonnage, tamping number per year, etc

• Proceedings of the KSR Conference
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• 2011.10a
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• pp.268-274
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• 2011

In railway, Ballast plays an essential role as intermedium in transmitting train load to subgrade safely. Gyoung-Bu HSL 1st phase consists of ballasted track except for over 5km long tunnels. Ballast track occurred track irregularity by train loads and requires periodic maintenance work. However, Repetitive train operation and tamping work cause to accelerate track irregularity and ballast deterioration such as abrasion and crushing. For these reason, Track irregularity areas had occurred ballast cleaning work to improve track quality. However, for the train to run safety, ballast cleaner working area needs train speed reduction and track stabilization work due to ballast relaxation and initial settlement. In this study, according to train speed-up and cumulative traffic tonnage, we measured and analyzed the track settlement and acceleration of sleepers to evaluate of track stabilization in order to keep the ballast condition stable after cleaning work.