NS Branch Mosquito Creek Bridge (Blue Mound)

Located along Illinois Route 48 northeast of Blue Mound, this small deck plate girder bridge carries the former Wabash Railroad across an unnamed branch of Mosquito Creek. The first bridge at this location was a timber trestle bridge, constructed when the line was initially built. During the early 20th Century, the Wabash made significant upgrades to this line, including double tracking the entirety of the line and replacing outdated bridges with steel and concrete structure. The segment between Decatur and Taylorville was double tracked in 1906, and an unknown bridge was constructed at this location. In 1915, the bridge would be replaced by the current through girder bridge. The bridge consists of a double track 30-foot deck plate girder span, set onto concrete substructures. The superstructure was originally installed at Bridge #89 on the Decatur Division near Milmine, Illinois; and was originally fabricated in 1905. After only ten years of use, Bridge #89 was filled and replaced by a culvert. This span uses an unusual design, consisting of two lighter outer girders and a heavy center girder. The girders are set below the track, but function similar to a through girder. In addition, these girders have square ends and a ballast deck, typical of Wabash bridges. It is currently unknown what contractor fabricated the superstructure, or what contractor constructed the abutments of the bridge. Railroads often reused steel spans, as it provided a cost effective way to replace bridges without requiring large amounts of new material. Girder spans were commonly used by railroads throughout the United States, as they were durable and easy to construct. Overall, the bridge appears to be in good condition, and appears well maintained. Little deterioration was noted throughout the bridge, and the superstructure of the bridge has a mainly intact coat of paint. Today, only the western track of the bridge remains in use. The author has ranked the bridge as being locally significant, due to the common design.