نتایج جستجو برای: ballasted railway track
تعداد نتایج: 76742 فیلتر نتایج به سال:
Single-track railway bridges are susceptible of experiencing high levels vertical acceleration on the deck that may be dangerously accentuated at resonance. This is especially critical for short-to-medium span simply supported bridges. problem can compromise safety trains and increase maintenance costs track. The main objective this work to investigate influence ballasted track dynamic behaviou...
This paper summarizes the results of laboratory tests in which authors investigated effects extremely high vertical load to a railway track segment. The segment consisted cut concrete sleeper (contact area: 290×390 mm) with pair direct-elastic rail fasteners; pieces had standard, full height; structure typical 350 mm depth ballast, underneath approx. 200 sandy gravel supplementary layer. whole ...
The dynamic analysis of railway vehicles involves the construction of three independent models: the vehicle model; the track model; and the wheel-rail contact model. In this work, a multibody formulation with Cartesian coordinates is used to describe the kinematic structure of the rigid bodies and joints that constitute the vehicle model. A methodology is also proposed in order to create detail...
One of the safety-critical components ballasted track systems is railway sleepers whose main functions are to (i) transfer vertical load, (ii) maintain rail gauge, and (iii) restrain longitudinal movement. Railway can be manufactured using timber, concrete, steel, composite, any other engineered materials. Prestressed concrete most commonly used type worldwide because their superior value-for-m...
one of the most important challenges in the development of urban railways network is the effects of railway vibrations on human and adjacent structures. although various investigations into the sources of railway vibrations have been conducted, very few research works have been reported on the influences of track geometry parameters on the level of vibrations. this is addressed in this research...
Development of an optimized strategy for the maintenance of Iranian railway track maintenance in a form of management system was made in this research. Through reviewing the current maintenance management system in the USA, Europe and Asia as well as investigating the characteristics of railway structure and current maintenance approaches in Iran, a new algorithm was made in order to improve ef...
Construction of railway track embankment over a soft subgrade will bring the necessity of using soil improvement methods for bearing capacity and settlement criteria satisfaction. As a practical improvement method, railway embankment filled with geofoam blocks is studied in this paper. First; a bilinear stress-strain model developed in FLAC2D to simulate geofoam embankment behavioral model. Sec...
Railway maintenance planners require a predictive model that can assess the railway track geometry degradation. The present paper uses a hierarchical Bayesian model as a tool to model the main two quality indicators related to railway track geometry degradation: the standard deviation of longitudinal level defects and the standard deviation of horizontal alignment defects. Hierarchical Bayesian...
Thorough understanding of steel rail response to wheel load is a key step towards design and evaluation of the railway track structure. In current practice, maximum vertical deflection and bending moment are calculated using the theory of infinite beam on continuous elastic foundation (Winkler model), in which the foundation stiffness is assumed as constant. However, variation of track modulus ...
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