BNSF I&M Canal Bridge (Joliet)

Located on the north side of Joliet, this massive through truss bridge carries the former Atchison, Topeka & Santa Fe Railway over the Illinois & Michigan Canal along the Des Plaines River. At this location, the canal empties into the Des Plaines River, where it follows the river through Joliet. The first bridge at this location was a 150-foot single track Pratt through truss span, constructed when the line was built in 1888. In 1906, the bridge would be shifted, and a second bridge of similar design added to the structure. By the 1930s, this configuration had become unfeasible, and the Santa Fe would begin planning to realign the tracks and construct a new bridge. In addition, during the early 1930s, the Illinois Waterway was being improved, with new movable bridges constructed over the Des Plaines and Illinois Rivers, completely rendering the canal obsolete. In 1935, the original crossing would be replaced by a larger double track through truss span. It is unknown if the old spans were reused, as the Santa Fe was often reusing 1880s spans for roadway overpasses at this time.

Currently, the bridge consists of a 200-foot, 10-panel, riveted Baltimore through truss span, set onto concrete abutments. Due to the curvature of the railroad, the span is heavily skewed, and is slightly wider than required for a double track bridge. The superstructure is heavily constructed, with massive built up members, heavy riveted connections, a heavy portal bracing and a ballast deck. Typical of Santa Fe structures, the ballast deck is constructed using parallel I-beams, placed between the truss lines. American Bridge Company fabricated the superstructure, and it is unknown if the substructure was constructed by railroad forces or by an unknown contractor. Baltimore trusses became popular in the 20th Century, as they provided an exceptionally strong design without sacrificing economy. These spans were also extremely versatile, and could be used in many situations. Since the initial construction, the bridge appears to be largely unchanged. Overall, the bridge appears to be in fair to good condition, with no significant deterioration noted. The author has ranked this bridge as being moderately significant, due to the truss design and newer age.