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IT <br /> DIETZGEN'S RAILROAD CURVE <br /> 7_�3� � AND � <br /> . v <br /> 'T 0 i REDUCTION TABLES. <br /> 71 n CbWrillht,1914,by Eume Dietwm Co..New York City <br /> -3 �f c q p <br /> a l <br /> 1_ a p 14-, k 7 _Z �/ �� 2 / Z ' �/ c j 4 <br /> � a <br /> 13 . S 7 s3 .7 � `� ; I 6a � Y y <br /> 33 <br /> Me /8 . <br /> CURVE FORMULAS <br /> : I <br /> ,����(1)Degree of Curve=D and sin.P=0 <br /> Radius—li= 2—g <br /> Tangent=T=Rtan (3)Length of Curve=L=1008(4) <br /> Middle ordinate=M=R(1—oos. (5) =Rvers (6) <br /> y76,4s External=E=Ttain4-(7)=R+ca.4 R(8)Rexae49) <br /> 7 <br /> I�� 3 •Ij Long Chord=C=2 R sin.z(10)A=Central Angle <br /> EXPLANATION AND USE OF TABLES <br /> Mations.--Given P. I.=Sta. 161+60.35.to find Sta. of P. C. <br /> • _. and P.T. 0=62° 10' D-._8°20'. From Table IV for 10 curve T_ <br /> 3 ! <br /> 3454.1 and i 8 X-414.49 ft. From Table V correction=.36 or T= <br /> 411.85 ft. P. C.=Sta. P.L—T=157-1-45.50. Also f cm (4) L— <br /> i F 746.00 and P.T.=Sta.P.C.+Ij—_164+91.50. <br /> Offsets.—Tangent offsets vary (a proximately) with <br /> D and with square of the distance. Thus tangent off9et r'Sts. <br /> b 9 1 8 t A_ ✓ 158 on above curve is 2.16 ft.found as follows. From Table III tangent <br /> II ! offset for 100 ft.-7.27 ft. Distance=158--Sta.P. C.==54.54hence <br /> Ll 47-0 offffset=7.27 (54.50+100)2=2.16 ft. Also square of any distahoe <br /> divided by twice the radius equals(approximately)the distance from <br /> U I 3 tangent to curve. Thus (54.50)2:(2 x 688.262.16 ft. <br /> Deflections.—Deflection angle-34 D for 100 ft., 1/D for 50 ft., <br /> 3 $ etc. For c ft-=0n minutes).3 x C x'D or=defl.for 1 `t.from Table <br /> III a C. For Sta. 158 of above curve=.3 x 54.5 x 8X=136.2! or <br /> 2° 16.2,or--2.50 x 54.5=136.2'from Table M. For Sta. 159 de9eo- <br /> "' ; I tion angle==r 16.21+80 201+2==60 26.21,etc. <br /> 4 ' 0 1 3 '� . 2 I Externals.--May be found in similar manner to tangents. Thus <br /> _ i f E for curve above is 91.37. For from Table IV for 1"curve E=960.8 <br /> for 8° 20'—MQ$+8h==:91.27 and from Table V correction=:10 or <br /> ¢ ff F1.37 . A sum <br /> 1 ) I F;ft. f6Pp � �and E is measured and found to be <br /> I <br /> W!y}t•ia-DY From Table IV E=230.9 and+42=5.5 or D= <br /> IEL Y Bt`s K <br />