Sunday, June 3, 2018

Aban/ICG/IC/OB&T Bridge over Missouri River at Omaha, NE

(Bridge Hunter, no Historic Bridges, 3D Satellite)
It was abandoned in 1980 [sign], which was before the ICG created the Chicago, Central & Pacific.
OB&T = Omaha Bridge & Terminal

Since the Iowa span is now always open, it is easy to determine that the view below is looking upstream. There are two swing spans because the Missouri River meandered.
Railroad Bridges, Related Photos and Video posted
Half of the old swing span is now over land because the 1957 Gavins Point Dam has reduced the flow of the river through this urban area. [Wikipedia]

Carmen Doughman, Aug 2017

safe_image for: There’s Something Incredibly Unique About This Abandoned Bridge in Nebraska[This article has lots of photos of the bridge.]

Brian Begley posted
Illinois Central swing bridge in Council bluffs Iowa. Looking towards omaha Nebraska across the Missouri River.

Brendan J Dock shared
Dennis DeBruler This bridge has two swing spans. The Iowa span is now always open.

One of 12 photos posted by Darcy Reimers

The Iowa side swing span was completed in 1893. This 520' wrought iron swing span was the longest of its time when built. It was designed for double-track and for roadways to be cantilevered outside the trusses. The roadways would accommodate electric cars, highway and pedestrian traffic. Since only a single track was laid and the roadways were never added, it had enough strength to carry more modern traffic loads. Only the swing span and its pier was permanent. The other piers were just pilings because they planned to add a more permanent bridge that would intersect the old bridge at the pivot pier. "Traffic was diverted from the old structure to the new simply by swinging the old draw span into line with the latter." [Railway Age, Volume 38, pp156-158]

The new bridge was built in 1903 using steel.
The original intention was to have a 560' fixed span, but this was abandoned in favor of the swing span for two reasons...:
(1.)  On account of the constantly changing channel of the river. It now must move soutside of the present banks to get from under one or the other of the draw spans.
(2.)  The cost of the additional draw and the substructure for the entire bridge on this bases was considerably less than for the structure with the fixed span. [Railway Age, Volume 38, pp156-158] [I do not understand why a movable span is cheaper than a fixed span.]
Since they planned to replace the old bridge from the beginning, I don't understand why they didn't use the sharper S-curve for the old alignment and then switch to more gradual curves with the new bridge.
[Railway Age, Volume 38, pp156-158]

[Railway Age, Volume 38, pp156-158]

[Railway Age, Volume 38, pp156-158]

[Railway Age, Volume 38, pp156-158]
The above was a view of the upstream side whereas below is the downstream side.
Council bluffs Public Library Flickr

Old and New IC Bridge - 1902.

Photograph of the old and new IC Bridge over the Missouri river. Council Bluffs, IA. Omaha, NE. 1902.

[Railway Age, Volume 38, p158

I knew the charter line of the Illinois Central went North from Cairo up the center of the state to Freeport and then turned west to Galena because Galena, with its river access and lead mines, had been an important town in Illinois for a while whereas Chicago was just beginning to grow thanks to the Illinois & Michigan Canal. And I knew that it crossed the Mississippi at East Dubuque after it went through a tunnel through the river bluff on the Illinois side. But I never paid attention to where it went in Iowa. IC owning a bridge near Omaha motivated me to find a map that included this western branch. We see the Iowa route went to Sioux City with some branches to other towns. Looking at a higher resolution map (after you find the map, click it, then click the box in the upper-right corner), the branch to Omaha left the mainline at Fort Dodge.
Dave Prasse posted

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