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I— z •�� Zs Cx 3.Ja I <br /> - <br /> z Z DILTZGENS RAILROAD CURS i <br /> AND <br /> REDUCTION TABLES <br /> CWrdZbt.1914,by EDietpra Cb.,Now York Cite, <br /> - _ - PG T <br /> 32od r' <br /> k-� 2y7.ss <br /> CURVE FORMULAS <br /> 7a? Radius=R= (1)Degree of Curve=D and sin.P=O(An.0/22 <br /> Tangent=T=Rtan� (3)Length of Curve=L=100$(4) <br /> Middis ordinate=M=R(1-cos. T)(5) -Rvers"(6) <br /> -- - - <br /> Exterml=E=Ttan`-(7)=R+cos. R(8)=Rexsec#(9) <br /> *G� S� fi,[ O — Long Chord=C.-2 R sin.'$-(10)o=Central Angle <br /> i - j i` --- - ---- EXPLANATION AND USE. OF TABLES <br /> 8tatioas.•-Given�P. 1.=Sta. 161+60.315 to find Sts. of P. C. <br /> and P.T. 10! D=S° 20'. From Fable IV for r durve T. <br /> 8454.1 and+SjJ--:14.49 ft. From Table V oorrection».36 or T= <br /> 414:85 it. P. C.—Sts. P.I.—T-157+45.50. Also from (4) L= <br /> 746.00 and P.T.=6ta.P.C.+D-164+91.50. <br /> Offsets✓--!Tangent offsets vary (approximately) directly with <br /> i, D aasd 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 /> offal%for 100 ft.-7.27 ft. Distanoe-158--8ta.P. C.=-54:504 hom <br /> offset-4.27 (54.30+100?-2.16 ft. Also square of any distance <br /> divided by I *a radiusequals(approxcimately)the distance from <br /> tangent to curve. Thus (54. 0"P+(2x 688.26)=2.16 ft. <br /> DdlecdonL--Deflection ft.--on <br /> D for 100 ft., 1/D for 50 ft., <br /> etc. For a ft. n igiautds).3 x C z °or—defl.for 1 it.from Tawe <br /> Wz C. For Sts. ,155 of above ourvem—A x 54.5 x 8 136.2' or <br /> _- r 18.2' ormd.5tft xi 54.5136.2'from Table M. For Eta. 159 dedse- <br /> _ boas Zj;;; '16.2'-W 2(Y+2-6°10.2,etc. <br /> j Xxonsala. -flay be,found is lar manner to tonus. 'Thus <br /> i9or curie above is 1.87. For from Table IV for 10+curve F3—M6 <br /> for;5° 2(Y-9Qi 6+891.27 aad from Table V correc tion- 10-or <br /> F,*91.87 ft. Or suppose and F is asessured and found to be <br /> --- 42 ft. What is D? From Table N.E—".9 and+42-5.6 or Dom <br /> - — 50 30'. <br /> a <br /> V <br />