نتایج جستجو برای: railway track
تعداد نتایج: 76624 فیلتر نتایج به سال:
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 ...
the vibrations produced by trains include two parts which are deterministic and random vibrations. due to variation of dynamic loads and patterns of load-time, the random vibration of moving train is one of the most important issues in the field of railway engineering. one of the important sources in producing the train vibrations is rail roughness and irregularities. in this paper, responses o...
Nonlinear hunting speeds of railway vehicles running on a tangent track are analytically obtained using Hopf bifurcation theory in this paper. The railway vehicle model consists of nonlinear primary yaw dampers, nonlinear flange contact stiffness as well as the clearance between the wheel flange and rail tread. Linear and nonlinear critical speeds are obtained using Bogoliubov method. A compreh...
Bicycling crashes on streetcar (tram) or train tracks: mixed methods to identify prevention measures
BACKGROUND Streetcar or train tracks in urban areas are difficult for bicyclists to negotiate and are a cause of crashes and injuries. This study used mixed methods to identify measures to prevent such crashes, by examining track-related crashes that resulted in injuries to cyclists, and obtaining information from the local transit agency and bike shops. METHODS We compared personal, trip, an...
In this paper, analysis for reducing lateral forces is implemented by using a railway vehicle model on a sharp curved track. Also, in order to minimize some problems when a railway vehicle runs on a sharp curved track, an active-steering bogie system is investigated. An active steering bogie system of a railway vehicle is designed to alleviate contact forces and to decrease wear of wheel/rail i...
The present contribution deals with the numerical modeling of railway track-supporting systems-using coupled finite-infinite elements-to represent the near and distant field stress distribution, and also employing a thin layer interface element to account for the interfacial behavior between sleepers and ballast. To simulate the relative debonding, slipping and crushing at the contact area betw...
The rail track is one of the most important elements of a railway system. During the passage of trains, the rails are subjected to contact load that comes from the wheels of the train. The railway track often fails in service due to wear caused by contact fatigue and other wear damage mechanisms that could also limit the life span of the railway infrastructure and railway vehicle. The aim of t...
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