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 98
the difference of level required.Thus, to find the difference of level between A and D (fig. 43), thelevel is first set between A and .B, and sights are taken on A and B;the level is then set between B and C, and sights are taken on B and * The level should be placed midway between the two points,… … usually divided into regularthe datum plane is required between C and D, and sights are takenon 6and D. Then the ditlcrence oflevel between ^1 and D \s E D ={BP+ KC-\- OD) — [AF-VBJ-\-NC). For E D == no - LC ^tlM-\-MC—L C. llutllM = h G= BF- AF, MC =^KC - DI,and L C =^ N C — 0 D. Sal)stitutingthese…
Railroad engineering · Ferrovias
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