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I i <br /> ' wrz 185 <br /> I . <br /> H aDIETZGEN'S RAILROAD CURVE <br /> YMnarl P hl� -• �.°IQ 1� .E Z o �2 , �1. , <br /> NOW Ca�a:a ��t �r�aks AND <br /> 6, I REDUCTION TABLES <br /> � ..p 1 3,� 8' � '-12 , � . <br /> l So 2L�-1 Coyyright,1914.by Eugene Dietmen Co.,Now York City <br /> O "s.3 0 .17 vc 12 <br /> 7' P <br /> 7 9fb-o tia�/��.dal _ � c� 5 � 1 •`l `6 3 _o� �- � S �5 <br /> k <br /> 12.'1''37 f3 <br /> +lr1 N cc o r• <br /> T r D__� ��( 4_„� :___� S• 4� _� _ _ (� ,,_.`� `� � CURVE FORMULAS <br /> •t CoTrco n c i,.,,, I ,_. <br /> of �3 ". <br /> Radius=R=sem(1) Degree of Curve=D and sin.z=s(2) <br /> 2.y7 Tangent=T=Rtan g (3)Length of Curve=L=100$(4) <br /> l « <br /> Middle ordinate=M=R(1-cos. j)(5) =Rvere o$(6) <br /> o <br /> External=E=Ttan 4-(7)=R 4cos. -R(S)=Rexaec J(9) <br /> Long Chord=C=2 R sin.s( 10)o=Central Angle <br /> (o ,1_1 g.. EXPLANATION AND USE OF TABLES <br /> 7_ J _ Stations.-Given P. I.=Sta. 161+60.35 to find Sta. of P. C. <br /> and P.T. A==62° 10' D-r 20'. From Table IV for 1° curve T- <br /> 3 y V. 3454.1 and+S%-414.49 ft. From Table V correction-_36 or T= ` <br /> �� 414.85 ft. P. C-Sta. P.L-T-157+45.50. Also from (4) L. <br /> 7 ,j,-(a 2 (,Q.q 746.00 and P.T.�ta.P.C.+1-164+91.50. <br /> j7A d1 - Offsets.-Tangent offsets vary (a roximately) directly 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 III tangent <br /> offset for 100 ft.=7.27 ft. Distance--158--Sta.P. C._54.50 hence <br /> 3 �- - _ offset--7.27 (54.50+100)2=2.16 ft. Also square of any distance <br /> divided by twice the radius equals(approximately)the distance from <br /> 3 V ✓� 1 '( `. tangent to curve. Thus (54.50)2+(2 x 688.26)==2.16 ft. <br /> Deflections.-Deflection angle-M D for 100 ft., 1/q D for 50 ft., <br /> 1'f-9-#-�_SL �!-I S to Z- . 3 8 _ etc. Fore ft.=(in minutes).3 x C x D°or�efl.for 1 ft.from Table <br /> III x C. 'For Sta. 158 of above curve=.3 x 54.5 x 8M 136.2' or <br /> i 1-�&_��1_•j 2e 16.2,or-2.50 x 54.5=136.2'from Table III. For Sta. 159 defleo- <br /> tion angle-cr 16.2'+8°20'+2=0 26.21,etc. <br /> EstarwhL-May be found in similar manner to tangents. Thus <br /> l« E for curve above is 91.37. For froth Table IV for r curve Fo=OWA <br /> $ N,Y�cerc_- o ktis3 40 0 i <br /> 57b Q �(o,� ,. for 8e 20' 80.6+8% 1.27 and from Table V correction=:10 or <br /> E=-91.37 ft. Or suppose &-W and E is measured and found to be <br /> J-14 c d m�a oadSr - 4 �. What is DY From Table IV E-30.9 and+42-5 5 or D� <br /> `� .. <br /> i <br /> v <br />