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/ ! I <br /> r _ <br /> DIETZGEN'S RAILROAD. CURVE <br /> AND <br /> T / e�.., F .. REDUCTION TABLES <br /> 4� �n �� %� r� 6 <br /> �eDY+li>zt.1614,fry Eugene McUgm Co.,New York Cky <br /> S <br /> k Q <br /> + -� <br /> L P, L?_7 ° <br /> je <br /> CURVE FORMULAS <br /> 9 Radiu1p=ft= 5 (1)Degree of Curv.=I)and sin.D_ao <br /> w` Tangent=T-Rtan'i (3)Length of Curve--L=1004(4) <br /> Middle ordinate=M=R(1-cos. (5) =Rvers A(6) <br /> s `� S External=E=Ttan;-(7)=R=cos.1j-R(8)=Rexsec#(9) <br /> f - v Long!Chord=C=2 R sin.42 (10)O=Central Angle <br /> EXPLANATION AND USE OF,TABLES <br /> Stations.-Given P. I.=StL 161+60-35 to find Sta. of P. C. <br /> ?x i and P.T, n==620 10' Die 20'. From Table IV for 1° curve T= <br /> ' 8454.1 and+8 §=+414.49 ft. From Table V correction=-,36 or T <br /> 746.00 and 14.95 ft.P T.=-Sts.P.CP.I+I�164+157 91.50 Also from (4) L= <br /> OStlets.--Tangent offsets vary (approximately) directly* with <br /> D and with.square of the distance. Thus tangent offset for 8ta. <br /> 158 on above curve is 2.16 ft.found ae follows. From Table III tangent' <br /> offset for 100 ft.-7.27 ft. Distanoe=15"ta.P. C.=54.50;hence <br /> /01` . ofreet-7.27 k54.50+100)2--2.16 ft. Also square of any distance <br /> divided by twice the radius uals(approximately)the distance from <br /> tangent to curve. Thus (54p-�(2 x ss8.2s}�2.16 ft. <br /> Deflections.-Deflection angle}. D for 100 ft., 3/D for 50 ft., <br /> etc. ' For o ft.-(in minutes).3 a C x D*or�defl.for hit.from Table <br /> IIl x a 16r Sia. 158 of above curve,".3 x 54.5 x 8q-136.2' or <br /> s ��d,2',aL '4.50 x BLL)=136.2'from Table III. For. Sta. 159 de8ec- <br /> owr.XW+802W+2=40 26.2',etc. <br /> NXISeaabar-+May.ba found in Apilar manner to.tangents. Thus <br /> E for our"above*91.37. For from Tzble IV for 1°curve E-W.6 <br /> for,8° 2(Y-4W 6+8%- 1.27 and from Table V correction-.10 or <br /> t X591.37 fL Or.suppose 4=82°and E is measured and found to be <br /> 42 ft. _What is DT. From Table IV E=230.9 and+42=5.5-or-per <br /> 5"30'. <br /> s - <br /> 10 <br />