• Proceedings of the KSR Conference
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• 2000.05a
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• pp.431-438
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• 2000

In recent years. the destructive force acting on the ballasted track is on the increase with the speed-up of trains and the number of trains, requiring more labor and expenditure to maintain the track in goof condition. Slab track has been developed to decrease the track maintenance work on earthworks. One type of slab track Rheda has Prefabricated track grid, consisting of rails. Prestressed concrete sleepers and reinforcement rods are aligned into position. and then concrete is then placed to integrate the sleepers into a reinforced concrete track slab. In this paper, a new analysis model for the system analysis of the slab track is presented. Then the analysis results are compared with requirements for slab track.

• Journal of the Korean Society for Railway
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• v.15 no.3
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• pp.251-256
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• 2012

Hanging sleepers are frequently observed in the ballasted track with the rail of high rigidity. These hanging sleepers at the high speed line could cause such large dynamic force compared to those at the conventional line. This dynamic force would, in turn, deteriorate train running stability as well as riding comfort, and accelerate irregularity of track and failure of track materials, leading to a sharp increase in track maintenance cost. When the wheel-rail contact spring exhibits nonlinear behavior and some components of the system like hanging sleeper exhibit bi-linear behaviors, an effective analytical method is proposed for train-track interactions. The verification of the present method is carried out comparing numerical results by the present method and those by Ono's method of RTRI.

• Proceedings of the KSR Conference
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• 2000.05a
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• pp.479-486
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• 2000

There has been recently an on-going effort in railway community to improve the dynamic performance of on-site railroad track with limited track possession time. In this paper, train running test lateral resistant force test and static/dynamic analyses are conducted before and after sprinkle of the ballast stabilizer in order to investigate the dynamic behaviors and parameters of the railroad track. Based upon the above results, effects of the stabilizer is verified, and a table for the track modulus representing on-site track condition and the methods to reduce the vibration and the transmitting forces of the ballasted track components to the infrastructures are suggested. It is thought that the suggestions made in this paper could be used as the preliminary data for the condition assessment and the maintenance of the track in the future.

• Journal of the Korean Society for Railway
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• v.9 no.3 s.34
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• pp.305-312
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• 2006

Gravel ballasted tracks are used as a basic structure for the domestic railway tracks. However, such kind of tracks has few disadvantages with service life of the structure, such as rapid deterioration of the tracks. Due to this reason, there is a need to develop low maintenance track to improve the service life of the conventional line tracks. CMP paved tacks are one of the kind of concrete tracks those were manufactured by using the prepacked concrete techniques. The purpose to develop paved tracks is to reduce the maintenance cost. The most important controlling factors to design the paved tracks are surrounding environmental condition and repeated train loading. In this study, in order to investigate the deformation characteristics such as displacement, earth pressure, strain ratio, and crack along the repeated loading cycle, cyclic loading test through real scale model was carried out.

• Proceedings of the KSR Conference
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• 2005.11a
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• pp.382-388
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• 2005

SMSC(Seoul Metropolitan Subway Corporation) is substantially taking the core role of mass transit system in Seoul Metropolitan area. When it was built, the design had challenged to sharp curved tracks less than 250m radius considering the protection of buildings and cultural properties as well as the connection to ground roads. Such circumstances have required a certain extent of slack in track geometry and therefore led to the construction of ballasted track with wooden sleepers. However, the dynamic force from running on sharp curved track has caused the misalignment and abnormal failure of track geometry, and it has resulted in a frequent maintenance and repair works which require a lot of cost and manpower. In this paper, we present the construction case of maintenance-free track system by using of concrete sleeper and elastic rail fastening system to ensure the safety of both passengers and trains, and to contribute the effective maintenance for track facilities of SMSC.

• Journal of the Korean Society for Railway
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• v.16 no.1
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• pp.40-46
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• 2013

Based on Korean railway design standards, the thicknesses of the reinforced roadbeds of conventional and high speed railways are different, and so too, for the size distribution of the ballast particles. Accordingly, considerable cost would be required to increase operating speeds of conventional lines, in particular related to changing from a ballasted track system to a ballastless one. In this study, applicability of a roadbed which supports conventional ballasted track, for use as a ballastless track for a high speed rail line was examined. A reinforced roadbed for a conventional railway is 20cm thick, and the type of material used for a conventional reinforced roadbed is M-40 (crushed gravel for road embankments). A dynamics test was conducted to evaluate the occurrence of the permanent settlement of the track substructure. These results suggest that, without changes to the track substructure, an operational speed of 400km/h is feasible with a ballastless track. This result; however, is from laboratory experiments. Further studies, such as numerical analyses or field validation, are required.

• Journal of the Korean Society for Railway
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• v.19 no.4
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• pp.498-505
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• 2016

As a basic study to develop maintenance-effective optimal ballast track in preparation for upgrading a conventional line to a high speed railway, a full-scale test that combined the components of ballast track was conducted and the characteristic of track settlement was analyzed. As a result of the full-scale test, reduction in maintenance via an increase of the elasticity of only the pad was insignificant; however, the effect increased significantly with increasing of the weight of the sleeper or with increasing of the weight of the sleeper and the thickness of the ballast together with use of a pad with high resiliency. An optimal type of ballast track, in line with upgrading the speed of a conventional line, shall be developed through cost efficiency analysis considering the maintenance cost depending on the track settlement as well as the initial construction cost.

• Proceedings of the KSR Conference
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• 2011.10a
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• pp.329-336
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• 2011

Urban transit is promoting improvement of the concrete track to solve many problems maintenance in ballasted track. But concrete track has a lot of noise compared to ballated track by multiple reflections. The concrete track is to install sound absorption blocks to reduce noise. And it has a lot of research and effort. This is study analyzed the effect of sound absorption blocks though field measurements, in the range of installed sound absorption blocks. And this was an analysis of the surface shape and sound absorption effects of sound absorption blocks.

• Journal of the Korean Society for Railway
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• v.10 no.5
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• pp.463-472
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• 2007

In this paper, the correlation between the vibration characteristics of the track components and the parameters affecting the vibration is analysed. To do it, the accelerations of each track component such as rails, sleepers and ballast are measured in Kyong-Bu high-speed line. The RMS values of the measured data are calculated and the pad stiffness, the longitudinal irregularity, running velocity and the corrugation, are considered as the parameters in the viewpoint of track. By using the linear regression, the correlation coefficient is calculated to analyse the relationship. Also, the 1/3 Octave analysis is calculated to analyse the dominant frequency band of tile vibrations of the track components.

• Journal of the Korean Society for Railway
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• v.12 no.1
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• pp.95-103
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• 2009

Deformations of bridge deck ends on abutments and piers bring about severe problems in track geometry and require maintenance work. In case of concrete slab track, more severe deformation and additional forces on rail and rail supports can be induced by bridge deck deformation, which affect the serviceability of track structure since concrete slab track is much stiffer than ballasted track and the behavior of track structure is integrated with that of bridge deck. In this study, the design variables affecting the serviceability of track structure are selected and the influence level is estimated by a parametric study. As a result, it is found that continuous span is advantageous than simply supported span and the stiffness of bridge bearing and rail fastener as well as the distance between last rail support and bridge bearing are most important parameters.