. Elements of railroad track and construction . , compute 0,the lead, and the radius of the turnout curve, (b) Samefrom the convex side. Problem 12.—(a) In a No. 12 turnout from the concaveside of a 4-degree main-track curve (R = ), compute ,the lead, and the radius of the turnout curve. (6) Same fromthe convex side. Problem 13.—(a) In a No. 8 turnout from the concave sideof a 6-degree main-track curve (R =), compute , the 120 RAILROAD TRACK AND CONSTRUCTION. lead, and the radius of the turnout curve, (b) Same from theconvex side. Problem 14.—(a) In a No. 6 turnout from the concav
. Elements of railroad track and construction . , compute 0,the lead, and the radius of the turnout curve, (b) Samefrom the convex side. Problem 12.—(a) In a No. 12 turnout from the concaveside of a 4-degree main-track curve (R = ), compute ,the lead, and the radius of the turnout curve. (6) Same fromthe convex side. Problem 13.—(a) In a No. 8 turnout from the concave sideof a 6-degree main-track curve (R =), compute , the 120 RAILROAD TRACK AND CONSTRUCTION. lead, and the radius of the turnout curve, (b) Same from theconvex side. Problem 14.—(a) In a No. 6 turnout from the concaveside of an 8-degree main-track curve (R =), compute ,the lead, and the radius of the turnout curve, (b) Same fromthe convex side. Article X. CIRCULAR THREE-THROW TURNOUTS FROMSTRAIGHT TRACK. 119. Turnout from Both Sides, Main Frogs Equal. —Required the frog-angle, F^, of the crotch-frog. In Fig. 71, the radii are equaland the frog-huimbers at B and Bare the same, and all are the triangle E 0 D. cos EOD OEOD or R and since R = 2 G N2 4N2 Fig. 71. cos I Fc 4N2 + 1 (31). 120. In the above three-throw switch, required thecrotch-lead and the number of the the triangle EOD, Fig. 71, ED = OE tan EOD, CIRCULAR TURNOUTS. 121 and since from (6) by analogy, cot § F^ = 2 N^, andfrom (9) R = 2 G N^, lc = Rtan|Fc = 2^ = ^ (32): Also ED =Vod2-OE2, orIc = V (R + A G)2 - R2 = VrG + i G2 = G V2 N2 + i (33) placing (32) equal to (33) and solving gives Nc = , (34). V2N2 + i If the i in (33) and (34) be neglected as small com-pared to 2 N2, making a difference of less than for No. 24 frogs, we have Ic =V2GN|(35),and Nc = -^ (36).V2 The distance between the main frogs and the crotch-frog measured along the main rail is 1 - Ic = 2 GN - G V 2N2 + i (37), or approximately 1 - Ic = (2 - V2)GN (38). 121. In the above three-throw switch, required theradius of turnout and the crotch-lead in terms of thecrotch-frog number. Referring to Fig. 71 and (36), we
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