This uniquely reused girder bridge crosses the former Milwaukee Road mainline near the town of Dedham.
Built in 1913, the bridge features a single through girder span. This span was originally fabricated in 1898 as part of a deck girder viaduct over Clear Creek near Rhodes, Iowa. However, a large number of these types of spans were reused by reconstructing the floor of a girder or pony truss span with new material, such as timber. This particular span was replaced by the present bridge in 1913.
Unlike other known Milwaukee Road overpasses, this girder features a triangular shape, as it was likely a main span of the Rhodes viaduct. However, it would not be unusual for a deck girder to be turned to a through girder, such as a the similar McKnight Road Overpass in Minnesota.
This practice was widely practiced among American railroads, particularly during times of high material cost. Oftentimes, these spans featured approaches of trestle, although this one features a concrete stringer span. However, most overpasses consisted of entirely wooden substructures. This bridge consists of concrete piers supporting the center span, an indication of the quality in construction of the new alignment in 1913.
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 to poor condition, with one large portion of severe deterioration on the south approach pier. However, this bridge was ranked as being "poor" by the National Bridge Inventory in 2009, but has since been deleted from the NBI. With an average daily traffic of 70, rehabilitation work was estimated at approximately $300,000 in 2009.
The author has ranked the bridge as being moderately significant, due to the old age and unique design.
The photo above is an overview.