Field-book for railroad engineers. Containing formulas for laying out curves, determining frog angles, levelling, calculating earth-work, etc., etc., together with tables of radii, ordinates deflections, long chords, magnetic variation, logarithms, logarithmic and natural sines, tangents, etc., etc (1877)
Henck, John Benjamin, 1816-1903 · New York : D. Appleton · leaf 36
= j^gives a = 4 Rb; a 2 JR b. Examples. Given 6 = 12, and a =^ 200, to determine R. Here2002 10000 12 ~ 833|. /i = 4X12 Given R = 675, and b = 12, to find a. Here a = 2^675 X 12 =2y8T00 == 2 X 90 = 180. 34. Protolem. Given the perpendicular distance between two par-allel tangents B D = b {fig- 7),… … Solution. Draw the perpendiculars E G- and FL. Then the righttriangles A B D and E A G are similar, since the angle B AD ^ i8 CIRCULAR CURVES. iAEC= AE G. Therefore AB : BD = E A : A G, or a : b 2Rb a Since a and a are (§ 32) parts of a, we have a = a — a. To find R the similar triangles A B D and…
Railroad engineering · Ferrovias
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