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IAIS Walnut Creek Bridge (South)

Pratt Pony Truss Bridge over Walnut Creek
West Des Moines, Polk County, Iowa

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Name IAIS Walnut Creek Bridge (South)
Built By Chicago, Milwaukee & St. Paul Railway
Contractor Wisconsin Bridge & Iron Company of Milwaukee
Currently Owned By Iowa Interstate Railroad
Length 142 Feet Total, 105 Foot Main Span
Width 1 Track
Height Above Ground 10 Feet (Estimated)
Superstructure Type Pratt Pony Truss and Trestle
Substructure Type Timber Pile
Date Fabricated 1896
Date Erected 1917
Original Location Bridge #R-18; Marquette, Iowa
Traffic Count 1 Train/Day (Estimated)
Current Status In Use
MILW Bridge Number Y-8
Significance Moderate Significance
Documentation Date September 2017


This Pratt Pony Truss bridge crosses Walnut Creek near the intersection of Grand Avenue and 63rd Street.
The main span of the bridge was fabricated in 1896 to cross Bloody Run Creek at Bridge #R-18 near Marquette, Iowa. In 1917, that bridge was replaced by a larger span, likely for flood control reasons and the span was moved to the current location.
The 6 Panel, Pin connected Pratt Pony Truss sits on wooden substructures and is approached by trestle approaches on either end. This type of truss is common on the Milwaukee Road, and it was a standard design from approximately 1895 to 1905.
Fortunately, the bridge continues to retain good historical integrity with little modification to the structure.

The author has ranked the structure as moderately significant, due to the truss design and age of the structure.
The photo above is an overview.

Citations

Source Type

Source

Build Date Milwaukee Road Archives at the Milwaukee Central Library
Contractor Missing Wisconsin Bridge & Iron Works plaque
Railroad Line History Source ICC Valuation Information, Compiled by Richard S. Steele