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EEL- <br /> WZ <br /> I><� i '�" - � DIETZGEN'S RAILROAD CURVE <br /> AND <br /> - i REDUCTION TABLES. <br /> - OoWrikht,1914,by Eveem Dish on Co. New York Cho <br /> PC T <br /> 4 <br /> - i <br /> CURVE FORMULAS <br /> Radius=R-53(1)Degree of Curve=D and sin.s=O C2) <br /> Q• O Taugent=T=RtanA (3)Length of Curve=L=100a(4) <br /> Middle ordinate=M=R(1—cos. b oo =Rvers (6) <br /> Eaternal=E=Ttan--(7)=R+cos.#R(8).=Rexasc4(9) <br /> Long Chord=C=2 R sin,4(10)A=Central Angle <br /> EXPLANATION AND USE OF TABLES <br /> 1- Stations.—Given P. I.=Sta. 161+60.38 to find Sta. of P. C. <br /> -- and P.T. A=452* 101.D=8°201. From Table IV for 10 curve T� ' <br /> L9 -f z`�S 2 Q 3 MKI and+8h=-414.49 ft. From Table V oorrection—.36 or T. <br /> 414.85 ft. P. C.—Sts. E.L—T�157+45.80. Aliso'from (4) h <br /> 746.00 and P.M—Sta.P.C.+LP-164+91.50. <br /> Offsets.Tangent offsets vary (a ro�amately) nth <br /> D and with square of the distsnrs. Thus tangent offr eta. <br /> 158 on above curve is 2.16 ft.found ae follows. From Tab1e:III tanSent <br /> offset for 100 ft.-7-27 ft. Distanoe�158-1NPi CJ-".50,hence <br /> _-- O� 1 okeet=7.27 (54.50+100)2=2.16 ft. Also square ofany distance <br /> divided by twice the radius eqquals(approximately)the diatsnce from <br /> Z 4- 2-0 �'/ /p tangent to curve. Thus (54.50p+(2x688.26')=2.16 ft. <br /> 4TA4 f v. X0j.0 Deflacbtoas.--Deflection <br /> angle-- D for 100 ft., D,for 50 ft., <br /> 73 Z 2 3 / 7 g etc. For o ft.=(in minutes).3 x.0 x- or=defl.for l t.from Table <br /> '� 3 Z. 1 � III x C. For Sta. 158 of above curve,—A x 54.5 x 8 =136.2' or <br /> ► r 16.21,orw4.50 x 54.5=136.2'from Table III. !For S� 159 de�- <br /> _ �� tion angle=-2"16.2'+8°20'+2=-&26.21,etc. <br /> �S'G t S6 7 <br /> Externals,—May be found id'similar manner to t angent�. Thus' <br /> — r ',E�60.6 <br /> ne / ? 0. fDr 8* 7 ft. Or supposee is 91.37. 7 and from Table IV for 1•carve =.IO or <br /> / -� 5 for 120' 960.6+ 1Q� and E 1s measured andounf d to be <br /> -- " 3 4 What is D? From Table IV E--W0.9 and+42=6.5 or Ds <br />