The Indianapolis journal. [volume] (Indianapolis [Ind.]) 1867-1904, 1883-12-06

Ing on either bank, between the two railroad
bridges which now span the gorge of the
Niagara above the rapids, less than two miles
below the cataract of Niagara. and in plain
sight of it, as he looks from one to the other,
is at once impressed by their dissmilaritv
They are not two minutes walk apart.
One is a suspension, the other a can
tilever bridge. These words to the general
public, who have never viewed either of
them, mean very little. To the engineer and
the mechanic they mean everything. The
suspension railway bridge is massive and
lmposing-a solid structure depending from
ten heavy wire cables, suspended from towers
of stone masonry SO high and SO solid as to
make them landmarks. The cantilever
bridge on the contrary, is light, airy and
graceful. Instead of being supported by ca
bles anchored to towers, its ends rest on
towers built up from the very verge of the
rapids, but so light that the spectator finds
it hard to realize that the latter graceful
structure is strong enough to support the
weight of heavy railroad train. Yet it is
beyond doubt that it will do so, and its COM
pleton adds new and wonderful scientific
achievement to the modern triumphs of ell
cheering
Honor to whom honor is due" No man
has been so well known to the army of work
men on the cantilever bridge, as we'll as to
the thousands of spectators who have lined
the banks and curiously inquired into the
tendent Ryland He has been the main
working spirit of the enterprise, and the fact
that the wonderful travellers" by which the
construction of the bridge has been so much
facilitated are his invention, shows his
efficiency. More remote from the public,
and from the actual conduct of the building
OF the bridge, is Gen. George S. Field, who
first conceived the idea of spanning the Nj
agara with a cantilevsr bridge. He drew the
first plans and had them accepted, and his
skill, energy and push have been very large
factors in the means which have produced
success. The bridge rests upon solid abut-
ments built up at the water-line. The top
of the stone foundations are fifty feet above
the water level, and from these the steel
towers supporting the cantilevers rise 100
feet. From the tower foundations up the
whole bri dge is of steel, every inch of which
has been subjected to the most rigid tests
from the time it left the ore to the time it
entered the structure. Between the towers
is clear span of 400 feet over the river--the
longest double-track span in the world.
The shore arm of each cantilever having
been built and anchored, the others to span
the river were constructed in sections of
twenty five feet, the whole being made self
sustaining as each section was added. The
ends of the cantilevers reach only $40 feet
beyond the towers, which left a gap of 100
feet to be filled. This vacuum has been sup
piled by an ordinary truss bridge, which
has been swung into place, and rests on the
ends of the cantilevers Here provision
is made for expansion and contraction
by allowing play between the ends of the
truss bridge and the cantilevers. At the
same time the bridge is thoroughly braced to
prevent danger from the lateral pressure of
the wind A local example of this dangeris
furnished in the fate Of the Lewiston sus-
pension bridge, five miles below, which, after
a successful operation as a footway OF four
teen years, was swept away by a terrific gale
that rushed down the gorge OF the Niagara
on a night in February, 1864. 1t is conf
IDENTIFY asserted that the "wave motion" pc
culiar to a suspension bridge-and anybody
who has ever been on such bridge during
wind need not be told what that is-will not
be felt at all on the cantilever bridge. The
total length of the structure is 995 feet, 1t
will have a double track, and will be strong
enough to bear two OF the heaviest freight
trains extending its entire length, and under
a side pressure of wind seventy. five miles
per hour, and even then it will be strained to
only one-ffth of its whole strength,