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_T_ 7F <br />I <br />r <br />II <br />j <br />I <br />E <br />si, <br />--- - i <br />DIETZGEN'S RAILROADS CURVE <br />AND <br />REDUCTION TABU <br />Cppyrigbt, 1914. by Eugene Dletzgen Co., New Yerk CHY <br />C[iRVE FORMULAS <br />60 1) Degree of Curve�.D and sin. <br />Radius--aR--in�l�( 1DU° (4) <br />Tangent=T=Rtau A (3) Length of Curve=L= Q n <br />0 �Rve_r — (6) a <br />1Wliddle ordinate=M=R(1�Os' �) (5) <br />External=E=Ttan (7') R cos.2 Rf8)— a <br />Long Chord=C-2 L=Central Angle <br />EXPLANATION AND USE OF TABLES <br />Stations.—Given P. I = 20'. 1From6 Table35 o11 for find S1° curve Tc• <br />or T— <br />and P. T. n=62° 10' D— 8°_ <br />3454.1 and-8�-414.49 ft. From Table Also from6(4) L= <br />414.85 ft. P. C"-sta. P.L= T —157 +45.6o. <br />�Sta P. 0-+L=lfi4 i 91rox directly with <br />746.00 $❑d P. T— <br />ent offset for Sts. <br />Offsets `Tangent offsets vary (antlroximately <br />D. and with Square of the distance. hus tangent III <br />tangent hence <br />158 on above curve is <br />2.16 ft. found us follow'- Table III sdistance <br />offset for 100 ft.: j( ft�Dilst6a ft "o square Of a <br />the distance from <br />-offset-7.27 (54.50 =100) — rwdrnatelY) <br />divided by twice the radius ecluals2{x 888.26) =2.16 ft. <br />tangent to curve. Thus (54.0) le � D for. 100 ft., D for 50 ft., <br />Deflections.— Deflection <br />angle , or—�defl. for 1 t. from Talo <br />etc. For c ft.=(in minutes) .3 x C x D <br />III x C. For 50 x 54 �59 of &1' from Table III.e curve For Sta 159 deflec- <br />t* 16.2', or= tangents. Thus <br />tion angle=2° 16.2' -i-8° 20 2 _6' 2$.2', etc. <br />Externals _.-May be found is similar manner to tang <br />E or <br />for curve above is i 15.37. 115.27 and frombTablele IV f'V correor I ction oncurve E= o b <br />for S° 20'-9611.6-8�a p2° and E is measured' �� 5 ortD= <br />und <br />E-115.37 ft. Or suppo 234.8 and <br />42 ft. What is D? kion' Table Iv E= <br />5° 30'. <br />