I&M Canal Trail - Fox River Bridge

Located on the east side of Ottawa, this unusual deck girder bridge carries the former Illinois Traction System over the Fox River. Originally, the Chicago, Ottawa & Peoria Railway crossed the Fox River at a bridge immediately downstream of the Main Street Bridge. This bridge consisted of three 5-panel, pin-connected Pratt pony truss spans, set onto concrete piers. The spans of this bridge were likely purchased from a steam railroad, and appear to have dated to approximately 1880. In the early 1920s, the City of Ottawa began pressuring the railroad to find new accommodations for the Fox River bridge. The bowstring truss bridge carrying Main Street had become outdated, and a new roadway bridge was required. A new concrete arch bridge at main street was constructed in 1923, and the railroad bridge removed at that time. Throughout the 1920s, the railroad planned a new crossing of the Fox River.

The chosen solution was to construct a new alignment parallel to the Illinois & Michigan Canal, reusing a part of the aqueduct over the Fox River to carry a new bridge. This aqueduct had originally been constructed in 1841 by David Sanger & Sons, and consisted of wooden pony truss spans, set onto stone substructures. A wooden towpath was constructed on the south side of the bridge, and the City of Ottawa added a pony truss bridge at a later date. The towpath was removed in the 1870s, and the original wooden aqueduct replaced with a steel span fabricated by Milwaukee Bridge Company in 1921-22. By the late 1920s, the aqueduct was in poor condition, and the railroad reached a deal to construct a new plate girder span where the towpath once was. As part of the work, the south side of the piers would be altered, and the remaining stonework encased in gunite. In preparation, the deteriorated roadway bridge was removed.

Contracts were awarded to the Mississippi Valley Structural Steel Company for the superstructure, and to the Gunite Concrete Construction Company for the alterations and repairs to the substructures. Throughout 1930, work progressed on the new "belt line" and bridge across the Fox River. Work began by removing the tops of the piers, and adding concrete. The remaining brick and stone was then encased in gunite. New deck plate girder spans were then installed on the piers, giving the bridge its current configuration. The bridge consists of eight 58-foot deck plate girder spans, set on substructures constructed of stone, brick and concrete. Although the line served interurban traffic, the deck plate girder spans appear to use a standard design for steam railroads, consisting of a heavy design. In addition, the bridge utilizes a ballast deck.

Mississippi Valley Structural Steel Company constructed a number of bridges for the Illinois Traction, likely due to their presence in Decatur. Deck plate girder spans were commonly used by railroads throughout the United States, as they were durable and easy to construct. The bridge was only in service four years before it was abandoned. It has since been converted to trail use, and serves the I&M Canal Trail. Overall, the bridge appears to be in fair to poor condition. While the superstructure remains in good condition, the piers and parallel aqueduct are in poor condition. Numerous repairs have been made to the bridge, and further repairs will be required in the future. Piers of the aqueduct and the abutments appear to have been repaired at a later date. Stone piers remain on the south side of the bridge, from the old roadway bridge. The author has ranked this bridge as being moderately significant, due to the reuse of the piers and the relatively obscure builder.