Shoshone journal. [volume] (Shoshone, Idaho) 1884-1931, 1917-01-12
Noteworthy Engineering Feat Achiev-
ed BY Union Pacific at
Omaha.

The engineering fraternity In par
ticuIar and the public in general will
be interested in reading Of the plac-
Omaha Of the new Union Pacific
bridge Older residents Of the state
need no reminder Of the place Omaha
held in their interest in early days.
The early day Ctahn was almost as
much al home on the streets Of the
Nebraska city as he was on East
Temple street. or Main street as it is
more popularity known The old
bridge across the lazy stream was a
familiar sight TO them.
Last Wednesday-the operation re-
quiring only about an hour. note
worthy engineering accomplishment
the newest bridge spanning the river
was moved into place and the old
bridge moved out Of the way While
the new bridge was being assembled,
the old structure remained in serv-
ice. At its side, however. there was
built a remarkable piece Of false
work The new bridge itself was
built on false work Between the two
were the permanent piers for the
new bridge, the same that were orig /
inally built under the old bridge
When the time came, section by sec
ton the old bridge was moved off the ,
piers onto the false work at its side 4
and in its place sections Of the new
bridge were moved The old bridge
viii remain on the false work until
it is taken to pieces and moved away
The first single rack bridge over
the Missouri river was completed in
1872. at an approximate cost Of l.
$50. Oe0. This bridge consisted Of II
spans OF trusses known as the Pot
type. each ESQ feet in length. the ap-
proach on the east side being solid
embanlment. and on the west side
trestle. which trestle was
later filled
In 1877, the two easteriy spans were
wrecked by a cyclone. and never re-
built. being replaced with timber tres
tie The sub-structure consisted of
II iron cylinder piers. and one stone
pier. at the extreme west end. all Of
which were founded on bed rock
Each iron pier consisted of two cylin-
ders 8 1-2 feet in diameter. placed
is 1-2 feet centers.
The bridge was commenced in 1855.
and completed for operation later in
the fall of 1887. 1t was double tracs
structure. consisting of four through
Whipple trusses. each 246 feet long,
with three deck spans at each end
The total length was about 1.750 feet
AT the time the bridge was erected
an extension was arranged for on
either side OF the main spans for one
roadway. and one sidewalk
The work of reconstrueting and re-
placing the old bridge was commenced
in May. 1916. and it was placed in ser
rice Immediately after being rolled ]
nto position Wednesday afternoon
December 20. The estimated cost is {
T. 900. 600. The bridge consists OF
through Pratt pin curved top chord
ipans 24s feet long. one through Pratt I
-iveted span $50 feet long. and two I
through Pratt riveted spans 12O feet q
ong. four deck plate girders ST feet
ong and two deck plate girders so I
eet long. for two tracks. The total ;
ength OF bridge is 1.723 feet. which q
loes not include approaches Thei 4
otal weight of the new bridge is about 5
leven and quarter million pounds. o
s. against five and half million q
ounds in the old bridge replaced. c
he height Of track above normal wa l,
sr In the Missouri river is about &c
set. q
The work undertaken consisted OF b
eplacing the entire super r-structure o.
nth new and heavier steel. the piers T
the four main river spans ii
smaining in place. The approach a
pans are supported with new con- cl
rete sub-structure. a
The four river spans were erected Il
n temporary pile pier extensions to "