نتایج جستجو برای: and rail costs
تعداد نتایج: 16840016 فیلتر نتایج به سال:
Elastic elements such as rail pads, under sleeper pads and under ballast mats are railway components that allow for a reduction in track deterioration and vibrations. And they are furthermore commonly used to obtain an optimal vertical stiffness of the infrastructure. However, the use of elastomeric materials can increase construction costs and the consumption of raw materials. Thus, the utiliz...
Rail inspection is an important task in railway maintenance. The speed and loads of trains have been increasing greatly in recent years, and these factors inevitably raise the risk of producing rail defects. Mainly the discrete surface defects impact the riding quality and safety of a railway system. However, it is a challenge to inspect such defects in a vision system because of illumination i...
This article develops an econometric analysis of metro station operating cost to identify factors that create variation in cost efficiency. Stations operating costs can be classified amongst the semifixed costs that a metro faces in the sense that they do not vary proportionately with metro output. They may therefore be important in determining the degree of returns to density. This article see...
In 1898, two railways serving the south-east of England agreed to be managed by a joint committee. This paper finds clear statistical evidence of the negative impact this had on total economic costs, including opportunity costs of capital, as well as working expenditure. Thus, additional support was provided for the then British railway policy already strongly suspicious of railway mergers on c...
In this paper, some practical solid transportation models are formulated considering per trip capacity of each type of conveyances with crisp and rough unit transportation costs. This is applicable for the system in which full vehicles, e.g. trucks, rail coaches are to be booked for transportation of products so that transportation cost is determined on the full of the conveyances. The models w...
rails fracture by the growth of fatigue crack or critical crack is one of the prevalent defects in railway. the rail fracture, failure and stress analysis should be studied in order to prevention of rail fracture. in this paper, new formulation of contact stress for two rolling bodies is presented, where the results are closed to the hertz stress formulation. moreover, stress analysis is done b...
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 identification of infrastructure critical to regional rail freight operations has many implications. Primarily, such a process informs policy-makers and directs funding to areas of high importance and/or greatest need. For the Chicago Metropolitan Agency for Planning (CMAP), analysts at Cambridge Systematics developed an infrastructure identification process designed to evaluate which key a...
We develop a model to determine the optimal structure and size of a rail car fleet at a chemical company under uncertainty in demand and travel times as well as substitution between rail car types. First, we formulate an MILP model that accounts for the substitution relations between the types and minimizes the total direct rail car cost under given rail car availability constraints and a prede...
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