. 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 . int of the frog. Fig. 16. Solution. Let the arc FB be the inner rail of the second branch,FG = R — ^g its radius, and B the tangent point where the turnoutbecomes parallel to the main track. Now since the tangent FK is oneside of the frog produced, the angle HFK= F, and since the angleof interse
. 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 . int of the frog. Fig. 16. Solution. Let the arc FB be the inner rail of the second branch,FG = R — ^g its radius, and B the tangent point where the turnoutbecomes parallel to the main track. Now since the tangent FK is oneside of the frog produced, the angle HFK= F, and since the angleof intersection at iTis also equal io F, BFK= ^ F {(^2, II.): whence BFH=hF Then (^ es) F G = ^r^^^^ , or R - :^-^^ (Tab. X. 9), or i Bi^= ^-^ iBF But BF sin. iF- sin 6tituting this value of ^ B F, we have ^9 -Sub R ^ ^ F In measuring the distance 11B = b, it is to be observed, that tb«leidths of both rails must be included. 36 CIRCULAR CURVE3. Example. Given 6 = 6 2 and i^ = 8^, to find R. Here 16 = 1 F = 4^ sin. 1^^/.^= F= 4 sin. /? —i^r = •.R = B. Crossinrjs on Straight Lines. 55. When a turnout enters a parallel main track by a second switcnit becomes a crossing. As the switch angle is the same on both tracksa crossing on a straight line is a
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Keywords: ., bookcentury1800, bookdecade1870, booksubjectrailroadengineering
