BOOK 072 - Laserfiche WebLink

Home Browse Search

l f TZ 7EN S .RAILROAD CURVE, � i3z! � AND z REDUCTION TABLES f--- ODWA&t,1914,by Eugene Dietsgon Co.,New York OW I PMI-7 e '70z I iso ',' s p 4, CURVE FORMULAS Y1 Radius=R=__50 (1)Degree of Curve=D and sin.a=a(2)n. +{ ` 4 Tangent= (3)Length of Curve=L=100,(4) U Middle ordinate=M=R(1—cos. (5) =Rvers A(6) 3 Y - -- External=E=Ttan--(7)=R+eos.4-R(8)=Rexsse4(9) 17 j � " ! Long Chord=C=2 R sin.A(10)O=Central Angle EXPLANATION AND USE OF TABLE.9 Stations.-Given I P. Lits. 161+60.35 to find Sta. of P. C. 1? and P.T. A=:b2° 101 D=8'20'. From Table IV for 1° curve T= 3454.1 and+83%414 49 ft. From Table V correction=36 or T� L i 414.85 ft. P. C.�t3ta P.L—T=157+45.50. Also from (4) L— ?(1 s PON" ! �'r 746.00 and P.T.—ata.P.C.+L=164+91.50. Offsets.—Tangent offsets vary (aThus y mately) directly with D and with square of the distance. us tangent offset for Sta. '158 on above curve is 2.16 ft.found as follows. From Table III tangent offset-for 100 ft.7.27 ft. Distance=15"ta.P. C.==54.50 hence / 5 offset=7.27 (54-50+100-2.16 ft. Also square of any distance divided by twice the radius equals(approximately)the distance from h _ tangent to curve. Thus (54-50)2+(2x:688.26)--2-16 ft. Deflections.—Deflection an e= D for 100 ft. \� angle--%% , Y4 D for 50 ft., G> t etc. For a ft.=(in minutes).3 x C x D°or�efl.for 1 ft.from Table III x C. For Sta. 158 of above curve=.3 x 54.5 x 8"-136.2' or 2° 16.2',or=%2.50 x 54.5=136.2'from Table III. For Ste. 159 deflec- - - - tion an 16.2'+8°20'+2=6°26.21,etc. BK* May be found in similar manner to tangents. Thus for curve above is 91.37. For from Table IV for 1'curve F=960.6 j f0r 8' 20'-460,6+834==91.27 and from Table V correction=.10 or - - - D-OL37 ft. Or suppose &---W and E is measured and found to be 4�ft:- What.is D? From Table IV F: =0.9 and+42=5.5 or D— s� J s,- i - ,