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DIETZGEN'S RAILROAD CURVE <br /> AND <br /> REDUCTION TABLES <br /> t CbWsisht,1914,by Eugene Dl."gen Co.,New Yeek COO <br /> A <br /> 01 <br /> F1 LD r- <br /> CURVE FORMULAS <br /> I <br /> Radius=Yt—50 (1)Degree of Curve=D and sin.D=se(2) <br /> Tangent=T=RtanA(3)Length of Curve=L=100,(4) <br /> Middle ordinate=M=R(1—cos. 3)(5) =Rvers (6) <br /> i External=E=TtanA-(7)=R-cos.g—R(8)=Rexsec$(8) <br /> I Long Chord=C=2 R sin.s( 10)o=Central Angle <br /> j EXPLANATION AND USE OF TABLES <br /> Stations.—Given P. I.=9ta. 161+60.35 to find Sts. of P. C. <br /> I and P.T. 0=62° 10' D=8° 20'. From Table IV for 1° curve T= <br /> - E 3454.1 and+8%=-414.49 it. From Table V oorreetion==�36 or T= <br /> - 414.85 ft. P. C.=Sta. P.I.—T=157+45.50. Also from (4) 1. <br /> 746.00 and P.T.=Sta.P.C.+L=164+91.50. <br /> Offsets.Tangent offsets vary (approximately) directlywith <br /> D and with square of the distance. Thus tangent offset fr Sta. <br /> 158 on above curve is 2.16 ft.found as follows. From Table III tangent <br /> offset for 100 ft.=7.27 ft. Distance=158- Sta.P. C.=54.50,hence <br /> offset-=7.27 (54.50+100)2=2.16 ft. Also square of any distance <br /> IF divided by twice the radius equals(approximately)the distance from <br /> I s _ tangent to curve. Thus (54.50)2+(2 x 688.262.16 ft. <br /> Deflections,—Deflection angle--% D for 100 ft., 1/D for 50 ft., <br /> i etc. For a ft.=(in minutes).3 x C x D°or <br />