Wentworth, G. A. (George Albert), 1835-1906 · Boston, Ginn & company · leaf 288
CURVES Principles. When it is necessary to change the directionof a railroad it is done gradually by a curve, usually thearc of a circle. Let AF andAO (Fig. 60) represent twolines to be thus connected.Take any convenient lengthAlB = AE = t. The inter-section of the perpendicu-lars BC and EC… … Fig. 60 Hence, r = t tan % A. 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, 50sin % D = — j and r = 50 esc -J- D. For example, a 6° curve has a radius of 955.37 feet. Sometimes the topography of…
Trigonometry · Surveying · Navigation
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