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. Railroad construction, theory and practice; a text-book for the use of students in colleges and technical schools, and a hand-book for the use of engineers in field and office . Fig. 149. Two other cases are possible, (a) r may increase until itbecomes infinite (see Fig. 149), then F = \f/, In such a casewe may write, by substituting in Eq. 86, 2R-d-K sin F = 4:n^{d-g-K sin F). (89). Fig. 150. This equation shows the value of R which renders this case pos-sible. (6) \J/ may be greater than F. As before (see Fig. 150). {2R-d-K sin F) : {d-g-K sin F) ::cot ^t^ : tan ^F; 2n(d-g-K sin F) tan ^xp
. Railroad construction, theory and practice; a text-book for the use of students in colleges and technical schools, and a hand-book for the use of engineers in field and office . Fig. 149. Two other cases are possible, (a) r may increase until itbecomes infinite (see Fig. 149), then F = \f/, In such a casewe may write, by substituting in Eq. 86, 2R-d-K sin F = 4:n^{d-g-K sin F). (89). Fig. 150. This equation shows the value of R which renders this case pos-sible. (6) \J/ may be greater than F. As before (see Fig. 150). {2R-d-K sin F) : {d-g-K sin F) ::cot ^t^ : tan ^F; 2n(d-g-K sin F) tan ^xp =the same as Eq. 86, but 2R-d-KBmF ir-\-hg = {R-^g-K sin f)- sin \p sin {yp-F) (90) §311. SWITCHES AND CROSSINGS. 353 Problem. To find the dimensions of a connecting curve run-ning to the INSIDE of a curved main track; number 9 frog, 4° 30curve, d = 13, sr = 48r. Solution.[Eq. 86] d = K=-100KamF =^= i2 = 2fl =((f+Z sin F) = 2B-d-K sin F = = = Since F>\p, we must use Eq. 87, rather than Eq. 90» iff = i2-fff-ii: sin if = = (i^-,/) =1855; log = sum = log 2n = log = co-log = log tan iiA = i^=2 55*20^=5*50 40F = 6°2135 = F-^=0° 30 55 log = sin ^= co-log = r =
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Keywords: ., bookauthorwebbwalt, bookcentury1900, bookdecade1920, bookyear1922