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The minimum railway curve radius is the shortest allowable design radius for the centerline of railway tracks under a particular set of conditions. It has an important bearing on construction costs and operating costs and, in combination with superelevation (difference in elevation of the two rails) in the case of train tracks , determines the ...
The larger the degree of curvature, the sharper the curve is. Expressing the curve in this way allows surveyors to use estimation and simpler tools in curve measurement. This can be done by using a 62-foot (18.90 m) string line to be a chord to connect the arc at the gauge side of the reference rail.
The Hallade method, devised by Frenchman Emile Hallade, is a method used in track geometry for surveying, designing and setting out curves in railway track. [1] It involves measuring the offset of a string line from the outside of a curve at the central point of a chord. In reality, string is too thick to provide a clear reading and breaks ...
On straight or tangent track, ideally there should be no variation, while on curves, a cant is generally desired. Curvature – The amount by which the rail deviates from being straight or tangent. The geometry car checks the actual curvature (in degree of curvature ) of a curve versus its design curvature.
The design pattern for horizontal geometry is typically a sequence of straight line (i.e., a tangent) and curve (i.e. a circular arc) segments connected by transition curves. The degree of banking in railroad track is typically expressed as the difference in elevation of the two rails, commonly quantified and referred to as the superelevation.
Given the allowed tolerance, it is a common practice to widen the gauge slightly in curves, particularly those of shorter radius (which are inherently slower speed curves). Rolling stock on the network must have running gear ( wheelsets ) that are compatible with the gauge, and therefore the gauge is a key parameter in determining ...
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A railway track (CwthE and UIC terminology) or railroad track (NAmE), also known as permanent way (CwthE) [1] or "P Way" (BrE [2] and Indian English), is the structure on a railway or railroad consisting of the rails, fasteners, sleepers (railroad ties in American English) and ballast (or slab track), plus the underlying subgrade.