The workingman's advocate. [volume] (Chicago [Ill.]) 1864-1877, 1877-04-21
THE SUSPENSION BRIEaE.


TORONTO, Canada, March 14.-The In
spection Of the suspension bridge at Mag.
ara is virtually finished, and the official re-
port will be published y. a few days. Ev-
ery link, spike, chain, bolt, anchorage,
and cable in the vast structure has been
carefully examined, and, as | am told by
one of the engineers, found TO be as good
as new, sound and reliable beyond ques-
tion. Whatever misgivings with respect
to this bridge may have been created by
the dissster at Ashtabula, the inspection
shows that they had no foundation.
Should the mighty arch 60 down into the
Niagara river to morrow, no coroner Jury
could ever find that the Great Western
railway had not done all that human fore
sight and engineering skill could suggest
to render such calamity impossible.
This bridge was built by Mr.. Roebling
in 1883 "a. Its four towers are each 80
feet in height and constructed of cuts stone
blocks 10 inches thick. The base of each
tower Is l6 feet square. Each tower Is
surmounted with an iron saddle with roll
ers upon which rest the cables, firmly hold
ing the saddle in position. The rollers al
low the cables to move easily, SO that IN
contraction and expansion there Is no ad
ditional strain upon thsm or the towers.
At all other POM Of bearing are cut-stone
caps securing everything from the action
of the elements. massive arch connects
the towers some I. } feet from the base
above, which is the railway track, and be.
low, the carriage way. The anchor pit,
cut in the solid rock, is 24x20 feet, and "a
feet deep, with drifts for anchor plates,
-. l.. II.
attached chains with links 200 pounds each,
which reach up through gains" cut in the
rock, where they connect with massive
wrought-iron shafts, over the ends Of
which is looped the wire that forms the
cables The wires, brought to . tension
of l, 2O0 pounds, are loOped upon the shafts
at the anchorage, which is filed with ma
sonry and concrete, rendering it almost
solid rock. The wire for the cables was
put through q process Of boiling in oil.
with q glutinous mixture, being kept in
the cauldrons thirty minutes, and then
dried i'll the sun. 1t passed through tins
process three times, the wire being thor
ouphly anne;Iled and rendered impervious
to water 1t was then sp el. Each cable
is composed Of {, 900 strands, which is 50
spliced as to be in fact one continuous
wire, 1, $50 miles In length. Each strand
was laid with tension Of 1900 pounds
As each cable contains ], $50 miles Of wire.
the four contain 5000 miles. The whole
weight Of wire is over 500 tons, giving .
safe working capacity Of 1900 tons II
is estimated, however, that the cables
would easily bear q strain Of 18, 900 tons.
Connecting these cables with the bridge
are go suspenders, each OF 80 tons capaci-
ty, with 90 guys fastening the bridge to
the river banks, extending from the center
to the rocks in su n manner A to prevent
lateral or lifting movement by the winds.
A single train extending from one end of
the bridge to the other with an engine and
tender weighing 90 tons, would weigh S26
tons, 30 that at their mean bearing capAci-
ty of IL, 900 tons it would take forIy trains
one piled on top Of the other to snap the
cables.
The engineers will report that there has
been no granulIzation, no corrosion, and
no settling. save the slight natural spring
! Of the cables. Cars have been passing over
the structure day and night these twenty
/ two years past, and frequently one thou
sand cara have crossed 1t in al, g'e day,
yet IL 10 absolutely ~ sound to lay - il
was when the frst train sailed over il IN
/ 1854.