Railroad engineers' field-book and explorers' guide; Especially adapted to the use of railroad engineers on location and construction, and to the needs of the explorer in making exploratory surveys

by H.C. Godwin

This historic book may have numerous typos and missing text. Purchasers can download a free scanned copy of the original book (without typos) from the publisher. Not indexed. Not illustrated. 1894 ...We thus have the point N. The curve NB is then located by using the same value of T, and the same offsets as before, only of course in reverse order. By obtaining n from the formula 71 d which gives its limiting value, we have a simple reverse curve without the intervening tangent but this is had practice when it can he avoided. Should the radius of JYB he required different from that of AM, the tangential distance for NB must then he calculated afresh. The advantages of this method are, that any length of intervening tangent can be used,--provided that the curves are carried up to the frogs,--so that the engineer can select any value of n for himself; and with simply a tape, he can locate the crossing in a manner a good deal simpler than the ways ordinarily in use. 120. As an example, let d = 40 feet and let No. 8 frogs he used; and suppose we select 1.3 as a value for n. Then from t he table, AF == 75.33, R = 603.02, mid D = 9 31',--the gauge being 4' 8-". Then from the above form nice we have nD = l.$ X 9 31' = 12D 22', t = 602.6 x vers 12' 22' = 14 feet, T= 602.6 X sin 12" 23 = 129 feet, ce = 12 X cot 12 22' = 54.7 feet, and 2/= 1.2 feet. The notes for the setting out of the crossing may then be arranged as P 23 3 £ Fig. 64. When the distance between the two tracks is great, the crossing should be run in with a transit, 121. If the turnout or crossing falls on a curve, it is best to locate it with a transit according to one of the two following 1. If the curvature of the main track is tolerably sharp and the distance d between the centres of the two parallel tracks comparatively small, we can avoid the insertion of a reversa curve without materially lengthening the crossing as In Fig. 65 let D = the degree o...

86 pages, Paperback

First published August 4, 2014