Lost Bridge Trail Bridge

Located along Illinois Route 29 west of Rochester, this through truss bridge carries the former Baltimore & Ohio Railroad across the South Fork Sangamon River. Little is known about the history of this bridge. It is likely that the first structure at this location was a timber pile trestle or timber truss bridge, constructed when the line was first built. In approximately 1890, the bridge would be replaced the present steel bridge set onto new stone substructures. Currently, the bridge consists of a 140-foot, 6-panel, pin-connected Pratt through truss span, set onto a stone abutment and pier. The truss span is approached by a timber pile trestle on the east end. Based on a missing plaque, the truss span was fabricated by the Union Bridge Company at the Athens, Pennsylvania plant. The truss uses a standard Union Bridge Company design, including built-up vertical members, a traditionally composed floor, a lattice portal and rounded heel bracings. In addition, the lower connections consist of a combination of pin-connected and riveted connections. A number of similar spans were constructed for different railroads in the early 1890s. It is believed that the stonework was constructed by an unknown contractor. Pratt trusses were the standard railroad truss design in the late 19th Century, as they were durable, economical, simple and easy to construct. This design was eventually superseded by riveted Warren spans in the 20th Century. Since the initial construction, the bridge has seen few changes other than the occasional upgrade of the timber approach trestle. Overall, the bridge appears to be in fair to good condition, with no significant deterioration noted. The bridge now serves as the highlight of the Lost Bridge Trail, and has been retrofitted with a wooden deck and handrails. The author has ranked the bridge as being regionally significant, due to the age and design.