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IAIS 420th Street Bridge

Deck Plate Girder Bridge over 420th Street
Hancock, Pottawattamie County, Iowa

Click the Photo Above to See All Photos of This Bridge!
Name IAIS 420th Street Bridge
Built By Chicago, Rock Island & Pacific Railroad
Contractor (Main Span) American Bridge Company of New York
Contractor (Approach Spans) Lassig Bridge & Iron Works of Chicago
Currently Owned By Iowa Interstate Railroad
Length 153 Feet Total, 65 Foot Main Span
Width 1 Track
Height Above Ground 15 Feet (Estimated)
Superstructure Type Deck Plate Girder
Substructure Type Concrete
Date Fabricated (Approach Girders) 1899
Date Erected 1952
Traffic Count 2 Trains/Day (Estimated)
Current Status In Use
IAIS Bridge Number 460.3
Significance Local Significance
Documentation Date October 2018
In 1867, the Chicago, Rock Island & Pacific Railroad continued building west from Newton, Iowa to Des Moines.

By 1869, construction would restart on the next 142 miles of track in Iowa, connecting Des Moines to the Missouri River. This trackage would be required to transverse some tougher landscapes, including large rolling hills and summits.

The railroad would be completed later that year, creating a continuous network for the Rock Island between Chicago and Council Bluffs.
In addition, trackage rights across the Missouri River Bridge at Omaha allowed for trains to access Nebraska and head to other points west.

In 1880, the railroad became the Chicago, Rock Island & Pacific Railway.

The railroad continued to see a growth in traffic, so it expanded the line. Significant portions were rebuilt west of Des Moines, including reduced curves and not as steep hills.

However, the biggest improvements took place in 1953. The Atlantic Cutoff was completed by September of that year.
The Atlantic Cutoff was an important improvement, reducing grades and creating a fast network. The Council Bluffs-Atlantic route shaved 10 miles off the old trip.

Because of this, the old line between Atlantic and Council Bluffs, including sections through Shelby and Avoca were abandoned.
In the end, the cutoff did almost nothing for the Rock Island. Interstate 80 opened only a decade later, closely paralleling the route.

By 1980, the Rock Island completely went bankrupt. The system was abandoned and chopped up.
However, in 1982, Iowa Interstate Railroad stepped in and purchased the Rock Island mainline between Chicago and Omaha.
Today, Iowa Interstate continues to operate the Newton to Council Bluff segment as the 4th Subdivision.
01/14/22


View an article regarding the construction of this route.

Located west of Hancock, this large girder bridge crosses 420th Street.
Built in 1952, the bridge consists of three deck girder spans. The center span was fabricated in 1952 and is original to this location. The approach spans were built in 1899, and came from an unknown location.
In addition, the approach girders are "twinned", creating a four girder span. It is unknown where these girders came from, or if they were all built in 1899. The bridge rests on concrete substructures.
The reuse of old parts in a new cutoff is a surprising find. This shows the desperation of the Rock Island to thrive.
Overall, the bridge appears to be in good condition.

The author has ranked this bridge as locally significant, due to the common design.
The photo above is an overview.

Citations

Source Type

Source

Build Date Rebuilding of Line
Contractors Plaques on bridge
Railroad Line History Source ICC Valuation Information, Compiled by Richard S. Steele



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