The Ketchum keystone. [volume] (Ketchum, Idaho) 1885-1899, 1889-10-12
A GREAT BaloeE.
The Largest Swing Span Draw-bridgt
in the World.

in the World.
The largest swing span draw
bridge in the world, that on the New
York, Providence and Boston Rail-
road, over the Thames river, was
swung into place at 5: 80 on the af-
ternoon of September 9Th. It's g.
100000 pounds of solid steel shot
into the mortices of the bridge
proper, and the double-rail tracks
locked together as naturally as
though they had been doing that
sort of a thing for the past twenty
years. The feat was performed in
the presence of crowds of interested
people, and it is regarded as an
other of the many triumphs OF engi-
neering which have been scored in
the erection of the great bridge.
Passengers over the shore line ferry
for months past have noticed that
the work on the swing span was rap
idly progressing. 1t was built along
the fender pier, up and down the
stream, and consequently offered no
obstruction to navigation, but grew
in size daily. An army of steel
workers and riveters have been en-
gagged upon it. Engineers speak of
structure of this kind as swung
when it is lifted clear of its false
works and its weight is carried by
the pivot pier. The trial was made,
as indicated, on Saturday afternoon,
and the engineers of the bridge we're
in great suspense until it was satis-
factorily completed, for it has re-
quired no end of skillful figuring
and engineering to accomplish this
feat with a double-tracked draw to
the unprecedented length of SOP
feet. It must be adjusted so nicely
as to admit of its turning in either
direction over the 225 feet Of clear
water on either side of the pivot
pier, and also to make complete
revolution. This was done on Sat
urday. Then the fine calculations
Of the engineers were apparent, for
with the thousands Of tons of con-
struction in the pivot pier and the
steel superstructure, when the great
draw swung into place, the eleva-
tions of the ends and the length
were as near the thousandths of an
inch as the most exacting of the
engineers desired. The draw will
sustain live weight of 5000 pounds
per foot of track. Trains will soon
begin running over the great bridge,
and from twenty to forty-fve min
utes Of vexatious delay by the sys-
tenn of ferry transfer between Bos-
ton and New York at New London,
will be gone forever. The matter
Of building the bridge, which is the
largest draw-bridge in the world,
has been discussed for over thirty
years. A. P. Bollar of New York
was finally engaged to make the
necessary surveys, and his plans
were approved by commission Of
engineers in 1883. Work was not
begun on the structure by the New
York, Providence and Boston Rail-
road, its owner, until early in 1888.
1t runs across the river from the
terminus of the Yale Harvard re-
gatta course at Winthrop and is
1922 feet long. The draw is flanked
on either side by spans of 80 feet,
and there are two other spans at
either side of the river of $50 feet
each. The unusual length of draw
was required by the United States
Government so that there should be
no obstruction to the passage of the
naval fleet to the Thames naval sta
ton farther up the river. The piers
of the bridge are still more unique
and expensive than the superstruc-
ture. There were great depths of
mud and water to be contended
with. In some places fifty-seven
feet of water and eighty feet of mud
were found where the piers must be
set. At these places the way to
build foundations was to construct
immense timber curbs, which were
then driven full of piles, which were
cut off at level midway in the
curbs. The spaces about the heads
of the piles were afterward filled
with concrete, which bound the
whole together and made a substan-
tial basin upon which to erect the
The center pier is an inn
mense structure, seventy-one feet
London (Ct.) Corr.
Boston Herald.