Influence of time-dependent material degradation on life cycle serviceability of interspersed railway tracks due to moving train loads

Kaewunruen, Sakdirat; Ngamkhanong, Chayut; Ng, Jipong

doi:10.1016/j.engstruct.2019.109625

Cited by 24 publications

(21 citation statements)

References 34 publications

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“…As can be seen from Figure 12, changing the modulus of elasticity has limited influence on the dynamic factors, ranging from 2.8 to 3.0. A similar finding could be reached for contact forces [51,52]. (Figure 12b) By contrast, the maximum bending moment distributions along a turnout are affected by different moduli of elasticity.…”

Section: Effects Of Sleeper Stiffnesssupporting

confidence: 78%

New Insights from Multibody Dynamic Analyses of a Turnout System under Impact Loads

et al. 2019

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A railway turnout is an essential infrastructure for managing railway traffic flexibility. In contrast, it imposes restrictions on train operations such as lower operational speeds through the turnout due to the complex movements of trains over the turnout. This results in the large-amplitude dynamic responses of the train-turnout interaction. Previous studies have focused on the train-turnout interactions entailing the wheel-rail contact forces and stresses. Very few of the studies considered the effects of the contact forces on the turnout structure and its components such as sleepers and bearers. Those previous studies neglected the dynamic forces and estimated the behavior of train-turnout interactions based on quasi-static calculations. In reality, turnouts are subjected to high impact forces, which can be higher than the permissible track forces. Consequently, a numerical model capable of determining impact forces was developed here, to evaluate the dynamic behaviors of a railway turnout and their effects on such turnout components as bearers, ballast, and so on. The model consists of a structured beam grillage laying on an elastic foundation with rigid wheelsets and a bogie. The model was verified by field measurements. The new insight stemmed from this study shows that neglecting the contribution of dynamic forces can result in the unsafe underestimation of train turnout behaviors.

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Section: Effects Of Sleeper Stiffnesssupporting

confidence: 78%

New Insights from Multibody Dynamic Analyses of a Turnout System under Impact Loads

et al. 2019

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“…The models used in this study were previously used to analyse the vertical responses of interspersed tracks under moving train loads. The results were validated using experimental parameters, field data, and previous laboratory results [18][19][20][21][22]. However, interspersed railway track buckling has never been investigated, so the validation of a plain concrete sleeper track was considered.…”

Section: Model Validationmentioning

confidence: 97%

“…Moving train loads were applied to interspersed tracks to study the vertical dynamic responses. It was observed that the replacement of timber sleepers by concrete tends to increase the deterioration rate of the railway track, as uplift behaviour occurs [21]. The condition of deteriorated interspersed track is presented in Figure 1.…”

Section: Introductionmentioning

confidence: 98%

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Buckling Analysis of Interspersed Railway Tracks

Ngamkhanong¹,

Wey²,

Kaewunruen³

2020

Applied Sciences

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Nowadays, timber sleepers are still used for ballasted railway tracks to carry passengers and transport goods. However, the process of natural decay causes the problem of timber sleeper degradation over time. A temporary “interspersed” approach is used to replace rotten timbers with concrete sleepers. This implementation has several inadequacies, as interspersed railway tracks have inconsistent stiffness and experience significant deterioration over the years. Increased heat due to the change in the global climate can induce a compression force in the continuous welded rail (CWR), leading to a change in track geometry called “track buckling”. A literature review shows that track buckling on plain tracks has been widely studied. However, the buckling of interspersed tracks has not been fully studied. This study presents 3D finite element modelling of interspersed railway tracks subjected to temperature change. The effect of the boundary conditions on the buckling shape is considered. The obtained results show that the interspersed approach may reduce the likelihood of track buckling. This study is the world’s first to investigate the buckling behaviour of interspersed railway tracks. The insight into interspersed railway tracks derived from this study will underpin the life cycle design, maintenance, and construction strategies related to the use of concrete sleepers as spot replacement sleepers in ageing railway track systems. The outcome of this study will help track engineers to improve the inspection of the lateral stiffness of interspersed tracks in areas prone to extreme temperature.

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“…According to open literature and industry knowledge, this practice could consequently undermine the existing ground foundations and also induce inconsistent local stiffness problems in the rail track system [13,[15][16][17] and in addition to different track decay rates [18][19][20][21][22][23][24][25]. Studies of interspersed tracks have been carried out [26][27][28][29] and it has been found that the replacement of timber sleepers by concrete possibly increase the deterioration rate of the railway track, as uplift behaviour occurs [29].…”

Section: Introductionmentioning

confidence: 99%