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IANR Rock Creek Bridge

Deck Plate Girder Bridge over Rock Creek
La Porte City, Black Hawk County, Iowa

Click the Photo Above to See All Photos of This Bridge!
Name IANR Rock Creek Bridge
Built By Chicago, Rock Island & Pacific Railroad
Contractor (Center Spans) Lassig Bridge & Iron Works of Chicago
Contractor (Outer Spans) American Bridge Company of New York
Currently Owned By Iowa Northern Railway
Length 140 Feet Total, 35 Foot Spans
Width 1 Track
Height Above Ground 15 Feet (Estimated)
Superstructure Type Deck Plate Girder and I-Beam
Substructure Type Stone Masonry and Concrete
Date Fabricated 1894, 1908 and 1939
Traffic Count 4 Trains/Day (Estimated)
Current Status In Use
IANR Bridge Number 133.1
Significance Local Significance
Documentation Date May 2018


Located south of La Porte City, this bridge features four random deck girder spans.
Much is unknown about this bridge. Iowa Northern Railway gave the dates of 1894 for two spans, 1904 for one span and 1933 for another span. However, inspections give dates of 1908 and 1939 for two spans, while the center two spans cannot be determined.
The center two spans appear to date to 1894. However, these spans are "twinned" deck girders, meaning each span has for individual girders. It is unknown if these were built this way originally, or if it was strengthened and/or moved here. In addition, the northern span has a 1908 plaque, and it is also unknown if it was moved here. The southern span is an I-Beam span and has a 1939 plaque, which may have been moved here after the Rock Island bankruptcy. The entire bridge rests on stone and concrete substructures.
Reusing spans was a common way for railroads to save money. Oftentimes, these spans would be strengthened upon relocation. Unfortunately, little information can be found on the bridge.
Overall, the bridge appears to be in good condition. The bridge was rebuilt in 2011 to replace failing components.

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

Citations

Source Type

Source

Build Date Iowa Northern Railway bridge records
Contractors Missing and intact plaques
Railroad Line History Source ICC Valuation Information, Compiled by Richard S. Steele