Omaha daily bee., 1883-05-25
A Gigantic Single Span Bridge.

The Buffalo Courier published q cut
representing a double track railroad
bridge now being built for the Canada
Southern railway across the chasm be-.
low the Niagara Falls and 300 feet
above the old suspension bridge. 1t
Is to be built on a novel plan called
the Csntilever. The total length will
be S95 feet; length of single span
across the gulf, SEQ feet; height of
stone abutmsnts on the edge of the
river, below the banks, on which steel
towers will rest, 80 feet; height of the
steel towers above the abutments, 100
feet; height of span above the river,
245 feet; weight Of bridge resting
on the towers, LOGO tons. The ques.
tion now Is how will they manage to
throw that immense span of 500
feet ACROSS the chasm2 1t Is impossi.
BILE to build s~caffoldings across that
almost fathomless torrent. We will
endeavor to describe how that span Is
to be thrown across. The center of
the top of the steel towers will be re.
spectively 1871 and 1879 feet from
the top of the banks, the towers rising
from close to the edge of the water on
the shores. On the top of each tower
will be built q cantilever, the center
of which will rest on the tower, some-
what like the swing bridge of our
viaduct, the center of which rests on
q stone tower, only the cantilever is
stationary. The length of the can't.
lever on the Caaa6a side will be 375
feet, and that on the American side
will be 295 feet. One.half Of q can't.
lever will be built from the top of the
bank to the top of the tower on each
side of the river. In order to do
this immense scs a 1ldings will
be erected, requiring 600 900 feet
of lumber. When these halves
are built they will simply be bridges
from the top of the banks to the top
Of the towers. They are made of the
best of steel, lsttice style, SO thor.
oughly stiffened that there will be no
spring or depression. The shore end
of each will be anchored In the rock
SO aa to require power equivalent to
400 tons to pull 1t out. Now the work
will commences of building across the
chssm, 500 feet, and 245 feet above
the water, without acatfoldlng to sup.
port 1t. A movable derrick Is slid on
top of the half cantilever, or bridge, to
the edge Of the tower on the river
side. A lattice section of the bridge to
span the chsam Is swung by the derrick
over the end of the bridge and secure.
ly fastened by a system of dovetailing
and boiling. Then the derrick Is sid
forward on to this projecting part and
another section Is hoisted over and
fastened In like manner, thus making
the bridge project fifty feet beyond
the top of the tower. The derrick
is slid forward again, and go on till
the river end of the cantilever Is fin
ished, projecting as 1t will on the
American side 1871 feet from the cen
ter of its tower and hanging that dis
lance over the gulf. II will be no
tioed that this cantilever rises on it,
center on the tower and the shore
end being anchored, the river end Il
capable Of sustaining four hundred
tons weight without any diree. sup
port underneath. After both These
cantilevers are finished, there still re,
mains . space of l25 feet TO bs
bridgsd. These two ends of the
cantilevers are united by q bridge O.
that length strung across by means Of
the derricks on the ends Of the two
cantilevers. Only two bridges of thil
style have ever been made, one In
Scotland and one on o railroad In
Pennsylvania. When this stee'
bridge at Niagara Falls IL finished, Il
will become Que Of the wonders Of
the world, and It will rank with the
highest of engineering works.