CN Otter Creek Bridge (Mona)

Concrete Slab Bridge over Otter Creek
Mona, Mitchell County, Iowa

Click the Photo Above to See All Photos of This Bridge!
Name CN Otter Creek Bridge (Mona)
Built By Illinois Central Railroad
Contractor Unknown
Currently Owned By Canadian National Railway
Length 220 Feet Total, 20 Foot Spans
Width 1 Track
Height Above Ground 15 Feet (Estimated)
Superstructure Type Concrete Slab
Substructure Type Concrete
Date Built 1914
Traffic Count 2 Trains/Day (Estimated)
Current Status (As of April 2021) In Use
IC Bridge Number 73.9
Significance Local Significance
Documentation Date April 2021
In 1858, the Cedar Falls & Minnesota Railroad constructed a line from Cedar Falls, Iowa to Lyle, Minnesota. The 77 mile line closely paralleled the Cedar River.

In 1896, the railroad became incorperated into the Dubuque & Sioux City Railroad. This railroad was a fully owned and operated subdivision of the Illinois Central Railroad.

In 1900, the Albert Lea and Southern Railroad extended the line to Glenville, Minnesota. This location was on the Burlington, Cedar Rapids & Northern (Rock Island) just south of Albert Lea.

The line immediately became part of the Dubuque & Sioux City Railroad.
The Dubuque & Sioux City ceased to exist, and became a full part of the Illinois Central in 1947.

The Illinois Central spun the line off to the Chicago Central Railway, a short line in 1985. The CC came back into Illinois Central in 1996.

In 1998, the Canadian National Railway gained control of the Illinois Central. Today, this line continues to be operated as the Osage Subdivision, with the portion south of Lyle, Minnesota (on the IA/MN Border) seeing steady traffic.

Located south of the small town of Mona, this concrete slab bridge crosses Otter Creek.
Built in 1914, the bridge features 11 concrete slab spans, set onto concrete substructures. This type of bridge was commonly used to replace pile trestles, as it was cheap to build, and oftentimes they were fabricated offsite.
Like many of these bridges, the slabs feature slightly decorative rectangles imprinted in the concrete.
Overall, the bridge appears to be in fair to poor condition, with significant spalling throughout the structure. A trestle just south of this bridge was found to be recently replaced when the author visited, and an access road was graded to this bridge. As a result, there is significant reason to think this bridge may be/have been replaced in the spring of 2021. When more information is available, the author will update this page.

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


Source Type


Build Date 1973 IC Track Chart
Railroad Line History Source ICC Valuation Information, Compiled by Richard S. Steele

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