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In this paper, the main factors in the analysis of the railway concrete sleepers areinvestigated and new recommendations are made in order to improve the accuracy of the currentpractices in analysis of the railway track system. First, a comprehensive literature survey isconducted, then, FEM models for a railway track system are developed and used to discuss andevaluate the assumptions commonly used in the analysis of the railway track system. The analysisfactors investigated include stress distribution under a concrete sleeper, rail-seat load, anddynamic coefficient factor. Finally, recommendations and needs for continuation of the researchare presented.

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Current practices in railway track analysis and design are reviewed and discussed in this paper. The

mechanical behavior of railway track structure comprising of various components has not been fully understood due

to the railway track structural complexity. Although there have been some improvements in the accuracy of current

track design methods in recent decades, there are still considerable uncertainties concerning the accuracy and

reliability of the current methods. This indicates a need for a thorough review and discussion on the current practices

in the analysis and design of railway track systems. In this paper, railway design approaches proposed by various

standards along with the results of a wide range of technical researches are studied and necessary suggestions are

made for the improvement of current practices in the analysis and design of railway track

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 Investigations on vibration behaviors of railway track systems were attempted in this research. This was made by conducting a comprehensive field investigation into the free vibration of track systems and response of tracks to train moving loads. In-situ modal analysis was used in a railway track field as an efficient method of investigating dynamic properties of railway track systems. Natural frequencies and mode shapes of the track system in different insitu track conditions were obtained for the fist time. The sensitivity of the natural frequencies of the track to the types of sleepers, fastening systems, ballast conditions, and rail joints were studied. Efficiency of rail welded joints in CWR tracks and the effects of replacing timber sleepers with concrete sleepers on dynamic behavior of a track were investigated. Advantages of flexible sleeper fastening system from the aspects of serviceability and passenger riding comfort were discussed. The effects of the track accumulative loading as a main indicator of ballast degradation on track dynamic behavior were studied. Rail deflections were calculated by using auto-spectra obtained from vibrations of the track under trainloads, leading to the development of a new mathematical expression for the calculation of the rail dynamic amplification factor.