• Journal of the Korean Society of Safety
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• v.32 no.4
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• pp.28-33
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• 2017

A sharp curved ballasted track on earthwork that was connected with a direct fixation slab track on steel box railway bridges have been deformed and damaged despite the frequently maintenance by a restoring force of sharp curved rail and track-bridge interaction forces such as axial forces and longitudinal displacement of continuous welded rail(CWR) owing to their structural characteristics, calling for alternatives to improve the structural safety and track irregularity. In this study, the authors aim to prove a cause of deformation for the sharp curved ballasted tracks to enhance the structural safety and track irregularity of ballasted track in service. A track-bridge interaction analysis and a finite-element method analysis for the sharp curved ballasted track were performed to consider the axial force and longitudinal displacement of CWR, the temperature and the effect of restoring force of sharp curved rail. From the results, the deformation of the sharp curved ballasted track with adjusted sleeper spacing from 833mm to 590mm were significantly reduced.

• Proceedings of the KSR Conference
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• 2011.10a
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• pp.2163-2173
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• 2011

In this study, the deformations and stresses occurred in the elastic rail fastening system were evaluated according to applied extreme track forces based on various field conditions, track curvature and poor properties. The purpose of this study is to establish a method for efficient management and suggest guide line for track construction in order to secure the performance quality of the elastic rail fastening system on the sharp curved track.. Therefore, initial construction qualities of rail and concrete bed, initial clamping force and applied extreme track forces were used into experiment as several parameters. Using these test results, the performance characteristics of the elastic rail fastening system were also evaluated. As a result, it suggested the method to secure long-term durability of fastening system and comparing sharp curved track to results on field test.

• 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.

• Proceedings of the KSR Conference
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• 2005.11a
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• pp.823-829
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• 2005

The extent of slack is correlative with the wheelbase of vehicle as well as the distance between the inner faces of flanges. Since the movable clearance of wheel flange is getting reduced in curved track, the vehicle is more difficult to negotiate the track. By this reason, a certain extent of slack is normally designed for curved track to allow the movable clearance corresponding to that of straight track. In case of some foreign railways,. the fixed extent of slack has been classified by the ranges of curve radius. In case of KNR, the slack is calculated by a formula for each case of curve radius and it therefore seems quite precise method. However, since there is a wide range of slack adjustment $(S'=0\~15mm)$ in calculation formula itself, too excessive or too little slack can be calculated. This study is to approach the technical review on slack calculation and to offer the reasonable slack design through the full-scale experiment at sharp curved track without slack.

• Journal of the Korean Society for Railway
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• v.17 no.1
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• pp.19-27
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• 2014

Urban railway vehicles operate in downtown areas. Due to increases in the number of passengers and changes in the service plans, railway vehicles are expected to operate on sharp curved tracks. However, on these tracks, the running stability of the railway vehicles is significantly decreased and the creepage is increased. Creepage causes the wheel/rail to wear and vibration. Therefore, reducing the creepage helps ensure the running stability and can be beneficial for the environment and cost. In this paper, the longitudinal creepage is analyzed using a railway vehicle model on a sharp curved track. Furthermore, in order to minimize the problems when a railway vehicle runs on a sharp curved track, the characteristics of a bogie are optimized using response optimization.

• The Journal of the Convergence on Culture Technology
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• v.7 no.3
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• pp.517-522
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• 2021

In this study, the causes of damage to the concrete sleepers in a ballast track with under sleeper pads attached to the base of the sleepers installed in the sharp curved track(R=180m) of the urban railway bridge were analyzed. The damage types of concrete sleepers were investigated, and the correlation with track irregularity was reviewed. Also, stress generated in the concrete sleeper was reviewed through structural analysis. As a result, most of the cracks of the sleepers occurred in the section with severe track irregularity. In addition, as a result of the analysis, the stress generated in the track components and the sleepers was found to be reduce in the fastening system using the 4-anchor.

• Proceedings of the KSR Conference
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• 2011.05a
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• pp.442-445
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• 2011

Concrete track on the new railway lines of the existing roads are built on high ground, or less than 400m radius of the sharp curve sectors will occur. sharp curve sectors the rail and wheel friction, stick-slip due to the band of 1,000Hz or squeal noise occurs from the increase in civil complaints about noise is a real situation. In this study, discussed in previous studies, noise measurements for each radius of concrete track and frequency analysis, followed by the radius of the curve in order to investigate vibration characteristics of urban railway sector sharp curve radius less than 400m and 400m ~ 1,000 m further to the point selected track components(rails, sleepers, ballast) according to the vibration measurements and analysis of the frequency characteristics and the results were derived.

• Proceedings of the KSR Conference
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• 2008.06a
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• pp.1689-1694
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• 2008

Recently, the development of the paved track is required as a low-maintenance of conventional line. The main reason is that the line capacity and bearing of track are increased progressively. The important factors of paved track are stability and applicability. To be based on this subject, cement mortar pouring type paved track is developed. The paved track is a kind of concrete track using the prepacked concrete technique. The most important thing to design the paved track is to optimize the track structure and materials considering various conditions. Until now, the paved track is verified a various material and structure test. In this paper, it is introduce to the test construction at the urban subway main line. The test construction is completed at Dec. 2007. A major object and substance is a guarantee of construction progress on main line, track performance, construction technique for curved section, transition zone and winter season, recycling the used ballast and application of specific sleeper for sharp curved section.

• Proceedings of the KSR Conference
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• 2003.05a
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• pp.82-90
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• 2003

The advance in technology of the CWR in Korea has led the establishment of the CWR on the sharp curve (i.e. less than R=600m). As thermit welding used in the sharp-curved construction site is carried out on the curve track, it is difficult to adjust a curve shape accurately and these difficulties have occurred in a number of cases. Therefore, in this study, the lateral buckling analysis of CWR track was carried out considering the actual ballast resistance force. In addition, the cant and vertical resistance force in ballast was considered in order to predict the initial behaviour of bucking in track under the more accurate method.

• Proceedings of the KSR Conference
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• 2004.10a
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• pp.348-356
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• 2004

In this paper, Analysis of parameters effecting on the derailment factor was conducted in oder to deduce technical requisites have to be reflected in design of Track and rolling-stocks because it is important to grasp the risk of derailment quantitatively. And then go far toward becoming practical study with that select two section of sharp curved track of actual train in service, incheon Metro Line 1 and make field research in condition of vehicles and track and analysis As a result of parameter study, the following conclusions were obtained. The radius of curve and Cant is in inverse proportion to the derailment factor, but as train operation velocity, standard deviation of alignment irregularity and the ratio lateral force : wheel load of the inside track increase, the derailment factor rise. In the investigation for the derailment safety of incheon Metro Line 1, the derailment factor was below 0.43 in both section R=200 and R=300, so that it proved safe compare with allowance limits 0.8, but it appeared that risk of the derailment in second transition curve is the highest among the entire curve.