Wentworth, G. A. (George Albert), 1835-1906 · Boston, Ginn · leaf 100
n to the excavation of Fig. 58- RAILROAD SURVEYING 91 SECTION XXIV CURVES Piinciples. When it is necessary to change the directionof a railroad it is done gradually by a curve, usually thearc of a circle. Let AF andAG (Fig. 60) represent twolines to be thus connected.Take any convenient lengthAB =… … For, in the right Hence, tan BA C = —— > or tan i- AAB 2 r — t tan-^1. The degree of a railroad curve is the angle subtended at thecentre of the curve by a chord of 100 feet. If D is the degreeof a curve and r its radius, 50 sin \ D = —} and r = 50 esc \ D. For example, a 6° curve has a radius…
Surveying
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