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80 - _ I <br /> Ltd S O K 21 g DIETZ.GEN'S•-'RAIL=ROAD -CURVE- <br /> Ft AND <br /> REDUCTION TABLES <br /> r <br />& G <br /> j R 1t6 <br /> / 3 of . 76 <br /> CURVE, FORMULAS <br /> Radius=R= na'33(1)Degree of Curve=D and sin.R �M <br /> Tangent=T=Rtsn"' (3)Length of Curve=L=100$(4) <br /> Middle ordinate=M=R(1-=cop. to) =$vera (8) <br /> External=E=TtaA'-(7)=R-cos. R(8)-Rexsee (9) <br /> Long Chord=C=2 Ti sin.s(10)&=Central Angle <br /> i o EXPLANATION AND USE OF TABLES <br /> k Stations.---Given P.•z.==8ta- 161+60.35 to 8nd 86& of P C. <br /> c r " a P. T. &=62° 10' D=8° 20'. From Table IV for'1° curve T= <br /> 8454.1 and+83 =414.49 ft. From Table V cornectionp—,36 or.T <br /> 414.85 ft. P. C.—Sta. P.I.—T�157+45.50. Also from (!) L® <br /> 746.0o and P.T.—Sta.P.C.+L.=164.+91.50. <br /> Offsets.—Tangent offsets vara (approximates directly <br /> D and with square of the distanee. T4us tange tj offror`SCa. <br /> 158 on above curve is 2.16 ft.found as follows. From Table III tangent r <br /> 1 offset for 100 f4.=7.27 it. Distance-15"ta.P. C.=54.50t hepo'c:e <br /> offaeta7.27 (54.50+100,}��L.16 ft. Asso square of any drataiaee <br /> � divided by twice the rediae oats(approximately)the distance from <br /> tangent ta curve. Thus (54 -t-(2x688.26) 2.16 ft. <br /> DeSectians.--Deflection angtr� D for 100 ft:, D for 50 ft., <br /> • etc. .For a ft.�(in minutes).3 X C 3D°.or�de8.for 1 Ott.fson► agile <br /> III x C For Sta. 158 of above ourve�.3 x 54.5 X$x)28 ':or <br /> 2° 18.2j,or-+x.50 x b4.5=136.2'from Tale III. F�it�ta. 1�..da>1eo- <br /> tion anglea2°16.2'+8°20 +2--$°262',etc: <br /> - xxteraals.--May be found in simiI'sr manner to t!!Wnts. us <br /> ar �bone i 891.37. Forfrom Table W for 1°curve F.�e <br />: Er 80 2(ft. 0. + ys�'1.27 sad from Table V correotion�.10.Or <br /> suppose &=.39{°1 and.E is measured and found$be <br /> 42 ft. What-is DY. Front Table.IV F,-=".8.and+42=44or'Dwa <br /> 5°30'. <br /> r <br /> t <br /> 1 , <br /> V <br />