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D BOOK Z04 <br /> FIE - DIETZGEN'S RAILROAD CURVE <br /> AND <br /> 4 REDUCTION TABLES <br /> Copsslsh�,2014,by Eur IHetspn Co.,New York ter <br /> PY T /. <br /> ` <br /> _ <br /> qt n <br /> 1 <br /> IV z <br /> , <br /> I CURVE FORMULAS <br /> Radius=R=a' 3(1)Degree of Curve=D and sin.z=s(2) S <br /> Tangent=T=Rtan'(3)Length of Curve=L=100$(4) <br /> Middle ordinate=M=R(1—cos l)(5) =Rvere$(6) <br /> F4dernal=E=TtanA-(7)=R+cos.#—R(8)—Rexsec#(9) <br /> Long Chord=C=2 R ein.z(10J A=Central Angle <br /> EXPLANATION AND USE OF TABLES <br /> Stations.--given P. I.--ata. 161+60.85 to find Sta. of P. C. <br /> { and P.T, &=-62° 10' D==8'20'. From Table IV for 1° curve T= <br /> 3454.1 and+83j- 414.49 ft. From Table V oorreWon�.36 or T= <br /> 414.g5 ft. P. C.�St 6 P.I.—T-157+45.50. Also from (4) L <br /> 746.00 and P.T.—Sta.P.C.+Lp-164+91.50. <br /> OQseEs.—Taageat offsets vary (approximately) direotl_y with <br /> D and with square of the distance. Thus tangent offset for Ata. <br /> } 158 on above ourve is 2.1$ft.found as follows. From Table III tangent,. <br /> offset for 100 ft.-7.27 ft, Distince�15"ta.P. C.—.54.50;hence <br /> offset-7.27 (64.50+100.16 ft. Also square of any' d*tance <br /> i divided by twice the rsdlgs eqqua� ls(approximately)the distsnee from <br /> tangent.to Curve. Thus (64.bO)1+(2 x 688.26)2.16 ft. <br /> Ds84etions.---Deflection angle—%D for 100 ft., 1/D for 50 ft., <br /> etc. For o ft mon minutes).3 x C x D°or—deft.for 1 ft.froom Table <br /> III x C. For Stn. 158'cif f# above 0urve—.3 x 54.5 x 8)j--436.2' or <br /> 7 16.21,or-2.50 x 54.5-136.2'f rom Table III. For BUL 159 defleo. <br /> tion angle=2'16Y+8°20'+2==6°26.2',etc. <br /> Rs —MPy be foundiagn/iml�ar manuer to tangents. Thus <br /> for curve above in 91.874 Far it om Table IV for 1°curve EP=960.6 <br /> pr 8* =wM6+834 .27 send from Table V correction�.10 Qr <br /> suppose A—Sr and E is measured and found to be <br /> 42 ft. What is DY Prom Table IV F-00.9 NW+42-5.5 or Da <br /> r <br /> s <br /> i <br /> r <br />