CN Bridge #458.8

Located alongside US Highway 30 and the former Chicago & North Western Railway mainline southwest of Dow City, this deck plate girder and concrete slab bridge carries a former Illinois Central Railroad mainline over an unnamed creek. The first bridge at this location consisted of a timber pile trestle bridge, constructed when the line was first built. In the mid to late-1910s, the IC invested significant capital into this line, rebuilding many timber bridges with concrete and steel bridges. The present bridge was constructed in 1919, using a span fabricated in approximately 1895 for use at an unknown location. It is possible that this span was reused from the Hyde Park (Chicago) grade separations, which had identical spans that were reused throughout the system. These bridges were fabricated in 1892 by Detroit Bridge & Iron Works in advance of the 1893 Chicago Worlds Fair. As the IC expanded operations in Chicago, the grade separations were replaced with modern structures in the late 1910s and early 1920s. Many of the spans from these bridges were placed between 1915 and 1921, and several were used throughout the IC system. Currently, the bridge consists of a 52-foot deck plate girder span, approached by a 14-foot concrete slab span on either end. The entire bridge is set onto concrete pile substructures. The main span follows a light version of a standard design, with two plate girders, an open deck and less bracing than 20th Century deck plate girder spans. The approach spans use heavy concrete slabs, which have no decorative features. The substructures are constructed using octagonal piles with concrete caps. An unknown contractor fabricated the main span, while the remainder of the bridge was constructed by railroad company forces. Railroads often reused steel and iron spans, as it provided a cost effective way to upgrade bridges without requiring large amounts of new material. Deck plate girder spans were popular for railroad use, as they were durable and easy to construct. Concrete slab spans became popular in the early 20th Century, as they were durable, easy to construct and economical. Since the initial construction, the bridge has seen no significant alterations, and remains in regular use. Overall, the bridge appears to be in fair to good condition, with no significant deterioration noted. The author has ranked the bridge as being locally significant, due to the common design and unclear history.