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79 FIELIDV� <br /> - DIETZGEN'S RAILROAD CURVE <br /> AND <br /> _ _ REDUCTION TABLES <br /> Coyvrisht,4914,by Eugene DietsW Co..New York CjfW <br /> 7' P <br /> Q <br /> 44 <br /> R I <br /> CURVE FORMULAS <br /> Radius=R=emM i (1)Dego of Curve=D and min.s=7t(� <br /> Tangent=T=Rtany (3)Length of Curve=L=100$(4) <br /> --- Middle ordinate=M=R(1-cos. (5) =Rvers A(6) <br /> External=E=Tian=(7)=R=cos.#R.(8):Rexaee#(9) <br /> Long Chord=C=2 R sins(10)G=Central Angle <br /> EXPLANATION AND USE OF TABLES , <br /> Stations.-Given P. I.=Ata. 161+60.35 to find Sta. of.P. C. <br /> and P.T. &=620 10' D=8"201. From Table IV for 19 curve T. � <br /> 3454.1 and+8%=414.49 ft. From Table V oorrecMon=_s36 or T- <br /> .414.95 ft. P. C.--9t86 P.I.-T-157+45.50. Also from' (4) 1- <br /> 746.00 and P.T.-Sta.P.C.+Lm164+91.50. 1 <br /> Offsets,-Tangent offsets vary (s roximatelp) dirga#((yy with <br /> ____• D and with square of the distance. Thus tangent offset for Sts. <br /> 158 on above curve is 2.16 ft.found as follows. From Table iTlgept <br /> offset for 100 ft.=7.27 ft. Distance�158-Sta.P. C,=<•54 <br /> 3& 1 C/ °- y`9. �vU- <br /> 1-7e <br /> offset�.27 (54.50+100j�=2.16 ft. Also square of agir <br /> divided by twice the radius equals( proummstely)the� t�Ecun <br /> --' sp <br /> tangetut to curve. Thus (54.50 +(2x888.26)=2:18 ft. <br /> __ _ ____-_-. Daffeetlons.-Deflection ang1�3S D for 100 ft. �jj�Irbr 5p <br /> _ � etc. For.o ft�(in minutes).3 x C x T5°or®defl.fos''�ftif frame Tle <br /> Mc bow. c 2° 18.2',orm2.50xb4.5�i36.2'from Table III. FO!� dsflc. <br /> tionan 162'+8° <br /> e _ Externslq Nay be found in similar 1uWrAr to Thus' <br /> E for curve above is 91.37. For from 7"IV fo#'It` g <br /> -` for 8e 2(Y=• .6+83j--91.27 and from T" V 30 or <br /> 3, 92.ej E=91.37 ft. Or 2 1s2 Fsupprom Table ose &—W and E is tneamuned and"fecund to be <br /> 5e 30'. IV E 30,8 and+4A- b or Ds <br /> V • <br /> i <br /> d <br />