نتایج جستجو برای: and rail costs
تعداد نتایج: 16840016 فیلتر نتایج به سال:
In this dissertation, we have developed computer vision methods for measurement of rail gauge, and reliable identification and localization of structural defects in railroad tracks. The rail gauge is the distance between the innermost sides of the two parallel steel rails. We have developed two methods for evaluation of rail gauge. These methods were designed for different hardware setups: the ...
the planning of a rail transit system is a complex process involving the determination of station locations and rail line alignments connecting the stations. There are many requirements and constraints to be considered in the planning process, with complex correlations and interactions, necessitating the application of optimization models in order to realize reliable and cost-effective rail tra...
Investigation of vertical vibrations of a railway turnout is important in designing track components under moving loads of trains. In this paper, the turnout is simulated by a linear finite element model with modal damping. A section of the turnout has a length of 36 sleeper spans surrounding the crossing. Rails and sleepers are modeled with uniform Rayleigh-
Timoshenko beam elements. The ra...
Investigation of the Influences of Track Superstructure Parameters on Ballasted Railway Track Design
The main design criteria of ballasted railway tracks include rail deflections, rail bending stresses, rail wheel contact stresses, sleeper bending moments and ballast sleeper contact pressures. Numerous criteria have been defined for the design of ballasted railway tracks owing to the various mechanical properties of track components and their complex interaction. Therefore, railway track desig...
A generation method for the rail random irregularity with arbitrary wavelength interval (WI) is developed, and its accuracy and efficiency are demonstrated. Then a moving wheel-rail-bridge interaction element is derived to establish the finite element equations of motion for the train-rail-bridge interaction system, and the flow chart of assembly and calculation for the system equations is give...
Pressure fluctuations during fuel injection are one of the factors that negative effect on performance of diesel engine. These fluctuations are caused by the rapid opening and closing of the nozzles and the creation of pressure waves in the fuel rail. One way to control these pressure fluctuations is to change the injector design and use an accumulator in the injector. This study is performed t...
Using multiple independent networks (also known as rails) is an emerging technique to overcome bandwidth limitations and enhance fault-tolerance of current high-performance clusters. This report presents the limitations and performance of static rail-allocation approaches, where each rail is pre-assigned a direction for communication. An analytical lower bound on the number of networks required...
the ability to perform rolling contact fatigue (rcf) experiments in wheel–rail material is provided by a new small–scale test rig, manifesting the actual dynamic behaviour of the railway system. in this paper, a multi-body dynamics (mbd) model is proposed, simulating the vibration behaviour of the prescribed rig. the new testing facility is modelled using a three-dimensional model of the vehicl...
This topic is very traditional and basically has been concerned for a long time. A lot of sophisticated vehicle/track interaction model and track dynamic deterioration model have been developed so far. The author also developed a track settlement progress model comprising a vehicle/track interaction model and a track settlement law. Hanging sleepers are usually caused more or less by the dyn...
This report evaluates criticism of rail transit systems. It examines claims that rail transit is ineffective at increasing public transit ridership and improving transportation system performance, that rail transit investments are not cost effective, and that transit is an outdated form of transportation. It finds that critics often misrepresent issues and use biased and inaccurate analysis. Th...
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