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`I+ <br /> ��EL so K ag 7 <br /> -� DIETZGEN'Sr RAILROAD CURVE <br /> AND <br /> REDUCTION TABLES <br /> CoWrisht,1914,by Eugene Dietmen Co.,14ew York Qb. <br /> PC T <br /> _ , Ct�`54•at�ra '�` � <br /> �.� ,ps4�� e4 aio or <br /> P7 <br /> CURVE FORMULAS <br /> Radius= Dsin. s z= (2)S sin 579 <br /> Tangent=T=Rtan6 (3)Length of Curve=L=1008(4) <br /> 'o7 A:5 ` a � <br /> Middle ordinate=M=R(1—cos. (5) =Rvers A(6) <br /> 4 "{ { { External=E=Ttan*-(7)=R=cos4—R(8)=Rexsec#(9) <br /> BM.Aldi I+rptl ay a s 3 ` (,._ Long Chord=C=2 R sin.s(10)A=Central Angle <br /> W¢sf Sid e <br /> EXPLANATION AND USE'OF TABLES <br /> tGt!<2 ! Stations.--Given P. I.=Sta. 161+60-35 to find Sta. of P. C. <br /> and P.T. p==62° 10' D---W 20'. From Table IV for 1° curve T= <br /> 3454.1 and+8h==114.49 ft. From Table V oorrection=.36 or T=; <br /> 4.5 0 � 8 � 414.85 ft. P. C.—Sta. P.L—T=157+45.50. Also from (4) L= <br /> uY v o• ¢.:. ,,i 746.00 and P.T.=Sta.P.C.+L=164+91.50. <br /> l , Offsets.Tangent offsets vary (appro�timately) directly with <br /> � � .� 3 3 to Thh ib <br /> D and with square of the distance. us tangent offset r Sta. <br /> 5Z4 ` .6 �� 158 on above curve is 2.16 ft.found as follows. From Table III angent <br /> offset for 100 ft.7.27 ft. Distance=158—Sta.P. C.==54.5%hence <br /> offset--7.27 (54.50+100)9=2.16 ft. Also square of any distance <br /> s <br /> an a U ;, r divided by twice the radius equals(a proximately)the distance from <br /> tangent to curve. Thus (54.50)9+(2x688.26)==2.16 ft. <br /> DeSections.—Deflection angle= D for 100 ft., Y4 D for 50 ft., <br /> , 2 etc. For a ft.---(in minutes).3 x C x or=defl.for 1 ft.from Table <br /> III x C. For Ata. 158 of above curve=.3 x 54.5 x 83•x=136.2' or <br /> 2° 16.21,or=-2.50 x 54.5=136.2'from Table TIL For Sta. 159 defleo. <br /> tion angie"2°16.2'+8°20'+2=6'26.2',etc. <br /> P • 'f J Externals.—May be found in similar manner to tangents., Thus <br /> E for curve above i6 91.87. For from Table IV for 1"curve Fp==960.6 <br /> for 8° 20' +$%=91.27 and from Table V cerrection=.10 or <br /> �o I�__' 0 { E�91.S7 fi. p=QW and E is measured and found to be <br /> 42 ft. 'I bAjs Rli'aern Table IV E-0.9 and+42=5.5 or D= <br />