A manual of the principles and practice of road-making: comprising the location, construction, and improvement of roads, (common, macadam, paved, plank, etc.) and rail-roads. By W. M. Gillespie ...

260 IMPROVEMENT OF THE SURFACE.
re-enter it after passing. The outside timber of each
track should be smooth on its upper surface, and the
inner one have hollowed in it a furrow, about 3 inches
deep, 4 inches wide at bottom, and twice that at top.
The flat timber should be wide enough to allow for the
usual variation in the widths of vehicles. Tile rise of the
road between the two timbers should just equal the depth
of the furrow, so that the two wheels may be on the
same level. The distance between the centres of the
timbers should be about 5 feet; between the two tracks a
space of four feet should be left; and on the outside of
each, nine and a half feet for a summer road, making a
total width of 33 feet, or two rods.
The railroad from Clifton to the Adirondack mines,
New York, is made of wooden rails. They are of hard
maple, 6 by 4 inches, and 14 feet long. They are set on
edge into notches in the ties, and are fastened by wooden
wedges.
IRON TRACKWAYS.
The wooden tracks, adopted more than two centuries ago
in the coal-mines of England, were before long covered
with thin plates of iron to increase their durability and tc
lessen their friction, and subsequently replaced by tracks
entirely of iron. While a flange on Fig. 120
their sides was used to keep carriages upon them, they were " tramroads," but when the flange was
transferred from the road to the wheel,
the trackway became a RAILWAY.
The extent of this topic demands for
it a separate chapter.