. Railroad construction, theory and practice; a text-book for the use of students in colleges and technical schools . ve, as shown in the accompanyingfigure. According to this system the length of run-off varies 86 RAILROAD CONSTRUCTION. §74. from 120 feet, for a superelevation of one inch, to 450 feet,for a superelevation of ten inches. Such a superelevationas ten inches is very unusual practice, but is successfullyoperated on that road. The curve is concave upward for two-thirds of its length and then reverses so that it is convex upward. TABLE FOR RUN-OFF OF ELEVATION OF OUTER RAIL OF CURVE
. Railroad construction, theory and practice; a text-book for the use of students in colleges and technical schools . ve, as shown in the accompanyingfigure. According to this system the length of run-off varies 86 RAILROAD CONSTRUCTION. §74. from 120 feet, for a superelevation of one inch, to 450 feet,for a superelevation of ten inches. Such a superelevationas ten inches is very unusual practice, but is successfullyoperated on that road. The curve is concave upward for two-thirds of its length and then reverses so that it is convex upward. TABLE FOR RUN-OFF OF ELEVATION OF OUTER RAIL OF in inches for each 30-foot rail commencing at theoretical point of curve. £.2 V i ¥ ¥ ¥ ¥ i 1 IV ir IF V ¥ r ¥ ¥ ¥ ¥ 1il ¥ N 5o W^ H 1 30 30 30 30 120 r 30 30 30 30 30 150 w 30 30 30 30 30 30 180 A 30 30 30 . 30 30 30 30 30 240 W 30 30 30 ... 30 30 30 30 30 30 ?70 6 30 30 30 30 30 30 30 30 30 30 300 7 30 30 30 30 30 30 30 30 30 30 30 330 W 30 30 30 30 30 30 30 30 30 30 30 30 360 9 30 30 30 30 30 30 30 30 30 30 30 30 _ 30 30 420 10 30 ■ ■ 30 30 30 30 30 30 30 30 30 30 30 30 •• 30 30 450. The figure (and also the lower line of the tabulated form)shows the drop for each thirty-foot rail length. For shorterlengths of run-off, the drop for each 30 feet is shown by the cor-responding lines in the tabular form. Note in each horizontalline that the sum of the drops, under which 30 is found, equalsthe total superelevation as found in the first column. Forexample, for 4 inches superelevation, length of curve 240 feet,the successive drops are i, i, Y, i] f, J, \, and \whose sum is 4 inches. Possibly the more convenient formwould be to indicate for each 30-foot point the actual super-elevation of the outer rail, which would be for the above case(running from the tangent to the curve) J, f, J, IJ, 2|,3i, 3r, 4. 74. Fundamental principle of transition curves. If a curve il § 75. ALINEMENT. 87 has variable curvature, beginning at the tangent with a curveof infinite
Size: 2775px × 901px
Photo credit: © Reading Room 2020 / Alamy / Afripics
License: Licensed
Model Released: No
Keywords: ., bookcentury1900, bookdecade1910, bookidrailr, bookpublisheretcetc
