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f <br /> DIETZGEN'S RAILROAD CURVE. <br /> i. <br /> AND <br /> rr3RECTION TABIrES <br /> k CoNri&t.1914,by Eugene Dietzgen Co..New York CHAV <br /> 7,1G <br /> f } <br /> 3� TU y <br /> A T�Sa�>,�'� -'.� -° .:�r vL%F,S�.�/C-/i✓ U�; .S�`�'F'/ i �z .7 6 -� <br /> I CURVE FORMULAS <br /> .5 /��<✓ C/.�'� Q�s,_�tel/ 1-4A41J !D6>}n//AJ /1 i go D so <br /> i <br /> Radius=R=e1n (1)Degree of Curve=D and sin.2=R(2) <br /> z/;' A-),? L/S � j Tangent=T=loan (3)Length of Curve=L=1QOD(4) <br /> Middle ordinate=M=R(1-cos. l)(5) =Rvers 2( 6) <br /> Extemal=E=Ttan s-(7)=R-cos.A-R(8)=Rexsec 4(9) <br /> Long Chord=C=2 R sin.a(10).A=Central Angle <br /> f { i <br /> EXPLANAT�* AND VSE.OF•TARL.ES <br /> Stations.-Given P. 1: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 /> j 3454.1 and=8�J=414.49 ft. From Table V correction-.36 or T= <br /> j 414.85 ft. P. C.=Sta. P.I.-T-157+45.50. Also from (4) L= <br /> f 746.00 and P.T.-Sta.P.C.+L-164+91.50. <br /> f i Offsets.Tangent offsets vary (approximately) directly with <br /> D and with square of the distance. Thus tangent offset for Sta. <br /> 158 on above curve is 2.16 ft.found as follows. From Table III tangent <br /> I offset for 100 ft.-7.27 ft. Distance=158--Sta.P. C.=54.50,hence <br /> { 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 /> tangent to curve. Thus (54.50)2=(2 x 688.26)-2.16 ft. <br /> Deflections.-Deflection angle=% D for 100 ft., Y4 D for 50 ft., <br /> etc. Fore ft.=(m minutes).3 x C s D°or==lefl.for 1 ft.from Table <br /> i III x C. For Sta. 158 of above curve=.3 x 54.5 x 8 i.6=136.2' or <br /> 2° 16.2',or=2.50 x 54.5=136.2'from Table.III. For Eta. 159 deflec- <br /> tion angle=2°16:2'-f8°20'+2==G*26.2',etc. <br /> Externals.-May be found in similar manner to tangents. Thus <br /> E for curve abovg4s 91.37. For from Table IV for 1°curve E=960.6 <br /> for 8° 20'=-960.6-t83jffi91.27 and from Table V correction=.10 or <br /> E-91.37 ft. Or suppose A==32°and E is measured and found to be <br /> i ! <br /> 42 ft. What is D7_ From Table IV E=230.9 and_42=5.5 or D-- <br /> 50 <br /> =5°30'. <br /> 4 <br /> i <br /> 1 <br />