نتایج جستجو برای: rail corrugation
تعداد نتایج: 10599 فیلتر نتایج به سال:
In this paper, we explore the transmission properties of single subwavelength apertures perforated in thin metallic films flanked by asymmetric configurations of periodic arrays of indentations. It is shown how the corrugation in the input side can be used to transmit selectively only two different wavelengths. Also, by tuning the geometrical parameters defining the corrugation of the output si...
Broken rails are the most common cause of severe freighttrain derailments on American railroads. Reducing the occurrence of broken-rail-caused derailments is an important safety objective for the railroad industry. The current practice is to periodically inspect rails using non-destructive technologies such as ultrasonic inspection. Determining the optimal rail defect inspection frequency is a ...
Direct numerical simulation was used to study laminar and turbulent flows in circular pipes with smoothly corrugated walls. The corrugation wavelength was kept constant at 0.419D, where D is the mean diameter of the wavy-wall pipe and the corrugation height was varied from zero to 0.08D. Flow rates were varied in steps between low values that generate laminar flow and higher values where the fl...
Running rails used as a return conductor and ungrounded scheme have been widely adopted in DC traction power systems. Due to the longitudinal resistance of running rails and insulation resistance of rail-to-ground, there will be a potential rise between running rails and the ground when return current flows through the running rails, which is known as rail potential. At present, abnormal rise o...
This report evaluates rail transit benefits based on a comprehensive analysis of urban transportation system performance in major U.S. cities. It discusses best practices for evaluating transit benefits. It finds that cities with larger, well-established rail systems have significantly higher per capita transit ridership, lower average per capita vehicle ownership and mileage, less traffic cong...
The paper presents the development of an intelligent image processing algorithm capable of detecting fatigue defects from images of the rail surface. The links between the defect detection algorithm and 3D models for rail crack propagation are investigated, considering the influence of input parameters (materials, vehicle characteristics, loading conditions). The dynamic behaviour at the wheel-...
Railway infrastructure monitoring is a vital task to ensure rail transportation safety. A rail failure could result in not only a considerable impact on train delays and maintenance costs, but also on safety of passengers. In this article, the aim is to assess the risk of a rail failure by analyzing a type of rail surface defect called squats that are detected automatically among the huge numbe...
Rail wheel squeal on curves in rail track is a source of potential noise annoyance to residents adjacent to rail lines. For one private rail freight operator, wheel squeal was causing repeated complaints from neighbours. Wheel squeal can be caused by the wheel-tyre to rail-top interaction and the wheel flange interaction with the gauge face of the rail (more like a screech). This paper describe...
Abstract: To ensure the rail transportations safety, evaluation of fatigue behavior of the rail steel is necessary. High cycle fatigue behaviour of a rail steel was the subject of investigation in this research using fracture mechanics. Finite element method (FEM) was used for analyzing the distribution of the stresses on the rail, exerted by the external load. FEM analysis showed that the ...
At present, high-speed rail is used only as a mode of passenger transport. Yet, the acceleration of logistics and freight transport flows could be compatible with high-speed rail capabilities. This article examines the experiences, literature and prospects of high-speed rail for freight. It uses three hypotheses to evaluate the development of freight high-speed rail services in Europe. The arti...
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