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BD <br /> ! <br /> I !RETURN TO <br /> COUNTY SURVEYOR'S OFFICE ! i DIETZGEN'S RAILR01D CURVE <br /> ! i 105 S. SUTTER SIYREET <br /> STOCKTON — CPJ�FORNIA i AND <br /> ' REDUCTION TABLES <br /> f <br /> J I (Wright.1914,by Eugene Dietsaen Co.,New York City <br /> ! <br /> PC T <br /> P <br /> i <br /> w + <br /> I c <br /> Q <br /> CURVE FORMULAS <br /> I Radius=R=0 n—m(1)Degree of Curve=D and sin. (2) <br /> 2 a <br /> Tangent=T=RtanA (3)Length of Curve=L=1008(4) <br /> Middle ordinate=M=R(1—cos. 3)(5) =Rvera (6) <br /> j, Eatelual=E=Ttan4-(7)=R=cos. It(8)=Rexsec (9) <br /> Long Chord=C=2 R sin.y(10)G=Central Angle <br /> EXPLANATION AND USE OF TABLES <br /> Stations.—Given P. I.aSta. 161+60.35 to find Ste. of P. C. <br /> T. &-620 10' Da8e 20'. From Table IV for 19 curve T= <br /> and+83%414.49 ft. From Table V oorreetion.�.86 or T= <br /> 414.85 ft. P. C.m Sta. P.L—T-157+45.50. Also from (4) '1:,= <br /> i 746.00 and P.T.—Sta.P.C.+1.i164+91.50. <br /> 1 Offaetse—Tangent offsets vary (apprmcmately) dirty with - <br /> J D and with square of the distance. Thus tangent offset'for Sts. <br /> &a on above curve is 2.16 ft.found as follows. From Table III tangent " <br /> �306et for! eet�+7.270(54.50+100)' t..`Also square of any d o <br /> vided by twice the radius equals(approximately)the distaste fripm <br /> Ungent to curve. Thus (54.50)2+(2 x 688.26)-2.16 ft. <br /> 1 <br /> Deflections.—Deflection angle,,!! D for 100 ft.,.4 D for 50 ft;_,+1 <br /> rete. Fore ft.—(in minutes).3x C x D*or—defl.for t ft.from Taklle <br /> III x C. For Sts. 158of above curve--.3 x 54.5 x 8X=13$.2' o <br /> 21 16.21,or-2.50 x b4.5-136.2'from Table III. For Sta. 159 def)�W„ <br /> tion angle=2e 16.2'+80 20'+2—ee 26.2',eta <br /> f Externals.—May be found jip similar manner to tangents. <br /> E for curve above is 91.37. For from Table IN for P curve <br /> I for 8e 20'--960.6+8%=-Ql.27 and from Table V correati�.l ,y <br /> f E==01.37 ft. Or suppose o=32e and E is measured and found to „.. <br /> 4o ft. What is DY From Table IV E=230.9 anti+42=5.5 or <br /> ! <br /> 50301. v <br /> i. Ps*C <br /> . o <br /> s <br /> v <br />