نتایج جستجو برای: ballast railroad track
تعداد نتایج: 67482 فیلتر نتایج به سال:
This paper presents findings from on ongoing research study at the University of Illinois focusing on the instrumentation and performance monitoring of railroad bridge approaches using multidepth deflectometers and strain gauges. Different sensors installed at the selected approaches are introduced, and details of the instrumentation activity are explained. Example track settlement data acquire...
This paper presents findings of a railroad ballast Discrete Element Modeling (DEM) research study focused on investigating ballast settlement under repeated wheel loading. In this approach, the ballast layer is modeled as an assembly of aggregate particles, AREMA No. 24 ballast gradation with different shapes and angularities and rough surface textures. The study matrix considered three differe...
One of the most important factors influencing the track maintenance is the transitions between parts of the track with different vertical stiffness. The dynamic...
During the study for the dimensioning as well as the selection of the individual materials constituting a railway track, the ballast and the substructure present residual deformations, directly related to the deterioration of the geometry of the track. The slighter the residual deformations and the slower their alteration over time is, the better the quality of the track. The actions acting ...
Railway transitions like bridge approaches experience differential vertical movements due to variations in track stiffness, track damping characteristics, ballast settlement from fouling and/or degradation, as well as fill and subgrade settlement. Proper understanding of this phenomenon requires the integration of field instrumentation with analytical and numerical modeling. This paper introduc...
Railway Sleepers are one of the most important elements in the track superstructure. Their tasks are keeping the track geometry, resisting against vertical and lateral train loads and transferring the train loads to the ballast layers. In this research, the railway sleeper as a beam on the elastic foundation is modeled with finite length. In this regard, two cases including a) beam with constan...
It is known, that track deterioration (loss of its geometry) strongly depends on track support conditions, particularly on the ballast. In this paper a novel approach is presented to predict the evolution of track vertical irregularities due to vehicle-track dynamic interaction taking into account ballast stiffness with dry friction. An applied vehicle-track model is composed of a railway car a...
A complete vehicle-ballasted track-bridge coupling dynamic model is established. A program to analyze dynamic characteristics is also invented, which is the first time to systematically analyze the dynamic characteristics of vehicles, tracks and bridges when using mats under ballast on the rigid foundation of bridge, in China. The results show that:(1) The mats under ballast are able to reduce ...
The correct assessment of the condition of a railroad requires the consideration of different factors. Some factors, such as the condition of the ties, can be measured by inspecting features visible from the surface of the railway. Other factors include the condition of the ballast; it is important to recognize the critical situation in which any foreign object can be present on the ballast. Th...
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