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390th Street Overpass

Recycled Through Girder Overpass over BNSF Railway
Aspinwall, Crawford County, Iowa

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Name 390th Street Overpass
Built By Chicago, Milwaukee & St. Paul Railway
Contractor Unknown
Currently Owned By BNSF Railway
Length 157 Feet Total, 41 Foot 3 Inch Main Span
Width 1 Traffic Lane
Height Above Ground 20 Feet (Estimated)
Superstructure Type Through Plate Girder and Trestle
Substructure Type Concrete and Timber Pile
Fabrication Date 1898
Erection Date 1913
Original Location Bridge #B-378; Prairie du Chien, Wisconsin
Average Daily Traffic 100 Cars/Day (Estimated)
Current Status In Use
BNSF Bridge Number 415.02
MILW Bridge Number Z-1333 1/2
Significance Local Significance
Documentation Date October 2018


This uniquely reused girder bridge crosses the former Milwaukee Road mainline near the town of Aspinwall.
Built in 1913, the bridge features a single through girder span. This span was originally constructed for railroad use as an approach span to the pontoon bridge at Prairie du Chien, Wisconsin in 1898. A large number of girder spans were reused by reconstructing the floor of a girder or pony truss span with new material, such as timber.
Nearly identical to the McKnight Road Overpass in Minnesota, this bridge features concrete piers and wooden trestle approaches. The girder features a hinged end, which functioned as a way to connect this span to the pontoon span.
This practice was widely practiced among American railroads, particularly during times of high material cost.
While many dozens of these such structures were built by the Milwaukee Road, only a few remain today. Most have been replaced due to low sufficiency ratings, as many of these bridges are substandard by modern standards. In addition, most of these bridges have received low sufficiency ratings due to deck issues, as well as inability to adequately inspect, due to a lack of structural plans which would contain details about the quality and size of materials used.
Overall, the bridge appears to be in fair condition, with some loss of the bases of the concrete piers.

The author has ranked the bridge as being moderately significant, due to the old age and unique design.
The photo above is an overview.

Citations

Source Type

Source

Fabrication Date Milwaukee Road Archives at the Milwaukee Central Library
Erection Date Date stamp
Railroad Line History Source ICC Valuation Information, Compiled by Richard S. Steele