...Railway artillery - Personal Page of GENE SLOVER

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to study a line answering all the technical conditions imposed, which
will be discussed in detail later. This line, drawn in a heavy or red
line on the map, permits the plotting of the longitudinal profile, in
which the distances between different points of the terrain appear as
abseissre and their elevation as ordinates, figure 2, plate 457. On this
longitudinal profile one may draw the red line or profile of the track
by ... series of grades joining the track of departure with the objective
without ever exceeding the maximum grade.
508. When the red line passes underneath the black line representing
the terrain the track is in cut; when the red line is above
the black line the track is on fill, figure 3, plate 457. The difference
in elevation between each point of these two lines of the profile
gives the height of the road bed above or its depth below tlie natural
surface. .
509; In taking account of the width of the road bed and its emplacement
one may, in utilizing only the longitudinal profile, compute
the volume of cut and fill necessary, and accordingly determine
the number of days' work. When the project is approved the line
is located on the ground; that is, it is staked out.
510. STAKING.-The numbered stakes of the preliminary survey
are useful in laying out on the ground the line adopted, the distances
from ihe line to these stakes being scaled from the map.
511. CENTER STAKEs.-The stakes are placed at the points of
tangency of the curve with the tangents. In the French Railway
Artillery Engineers' Service, these stakes are painted white and
carry the letter /I T" with a number in order; intermediate red
stakes, of which the numbers are of the same series as the preceding
ones, are placed every 50 meters, on tangents, and every 25 meters
on curves. A tack is driven in the stake at the center of the track.
512. ELEVATION STAKEs.-These stakes are set in such a manner
that the head has the elevation of the top of rail. They are placed
at the side of the track, about 21 meters from the rail. Breaks in
grade are painted in yellow and marked /I C. P.," with a serial number
on stakes. Intermediate stakes of the same color every 50
meters are numbered in a series distinct from that of the line stakes.
513. SPECIFICATIONS OF STANDARD TRACK.-Minimum radius of
curves, 150 meters; tangents to be inserted between reverse curves,
25 meters; maximum grade on tangents and on curves above 150
meters radius, 20 millimeters per meter, or 2 per cent. Reverse
grades should be joined by a vertical curve of 1,000 meters radius.
Gauge, distance between the inside of the heads of the rails. The
gauge used for artillery is slightly wider than for standard track
work, e. g., tangents and curves over 150 meters radius (4 feet, 8.875
inches), 1.445 meters; curves of less than 150 meters radius (4 feet,
9.312 inches), 1.445 meters. Spacing, C to C, of ties, 0.80 meters;
Digitized by Coogle