UP Raccoon River Bridge (Hollingsworth Spur)

Located near Valley Junction in Des Moines, this deck plate girder and steel stringer bridge carries a former Minneapolis & St. Louis Railway spur across the Raccoon River. Little is known about the history of this bridge. It is believed that a previous bridge at this location was constructed in 1878 to serve a coal mine nearby. This bridge likely consisted of a timber pile trestle structure. It is believed that the bridge was renewed in-kind at least once. In 1918, the M&StL decided to rebuild the bridge with a large center span, likely to improve flooding and driftwood issues. Work on the project began in late 1918, and was completed in 1919. Initially, the bridge consisted of a 100-foot deck plate girder span, set onto concrete piers and approached by timber pile trestle spans on either end. Koss Construction Company was reportedly the contractor for constructing the concrete piers. Throughout the remainder of the 20th Century, the approaches of the bridge were renewed with in-kind materials. In approximately 2000, aerial photos show a series of steel stringer spans laid out near the south end of the bridge, which were to be installed to replace the original approaches. After a flood in the early 2000s, Union Pacific Railroad began the project of completely rehabilitating the bridge in 2004. As part of the work, the original concrete piers would be demolished, new piers constructed and the approaches rebuilt with a series of secondhand steel stringer spans, acquired from a variety of unknown locations. Currently, the bridge consists of a 100-foot deck plate girder span, approached by four steel stringer spans on the south end and three steel stringer spans on the north end. The entire bridge is set onto steel pile bents and piers.

The main span of the bridge follows a heavy design, consisting of two massive plate girders and an open deck. Except for the north span (span #8), the approach spans all generally use an arrangement of four beams, arranged into two sets of two. The north span (span #8) consists of six beams, arranged into two sets of three. All of the approach spans appear to have originally been constructed in approximately 1930, and were reused from as many as seven unknown locations. Because UP supplied the beams, it is also unclear if the spans were originally constructed for the UP; M&StL; the Chicago & North Western Railway (C&NW); the Chicago Great Western Railway (CGW); the Chicago, Rock Island & Pacific Railroad (Rock Island) or any other railroad that was eventually acquired by UP. It is also possible that these spans had been salvaged from an abandoned line, from a replaced bridge or from an unused second track. All substructures of the bridge are constructed from steel H-piles, and concrete backwalls are used at the abutments. Wisconsin Bridge & Iron Company fabricated the main span; while multiple unknown contractors fabricated the approach spans. It is believed that the steel substructures were constructed by railroad company forces. Missing plaques are present on span #2 and span #8. Deck plate girder and steel stringer spans were popular for railroad use, as they were durable and easy to construct. Railroads have been reusing steel and iron bridge spans since the 19th Century, as it provided a cost effective way to upgrade bridges without requiring large amounts of new material. Today, the bridge remains in use as a spur to serve a cement plant. Overall, the bridge appears to be in good condition, with no significant deterioration noted. The author has ranked this bridge as being locally significant, due to the unknown history and common design.