BNSF Spoon River Bridge (Dahinda)

Located on the east side of Dahinda, this large through truss bridge carries the former Atchison, Topeka & Santa Fe Railway over the Spoon River. The first bridge at this location was likely a steel truss bridge, constructed when the line was built. In 1910, the Santa Fe continued to double track this line, and the present structure would be built. The bridge consists of a 220-foot, 9-panel, pin-connected Parker through truss span, approached by a 105-foot 6-inch "Class DD" through plate girder span on either side. The entire bridge is set onto concrete substructures, and utilizes a ballast deck. The main span of the bridge is exceptionally heavily constructed, using massive pinned connections and heavy built up members. The floor of this span is constructed of parallel floorbeams, and the ballast channel of the bridge is integral to the superstructure. Typical of 20th Century Santa Fe truss spans, the lower connections are parallel with the top of the ballast channel, instead of at the bottom of the floor. The through plate girder spans follow a standard Santa Fe design, with rounded edges and large plate girders. While most railroads stopped using pin connected spans by the turn of the 20th Century, the Santa Fe continued to rely on this design into the 1920s. 20th Century Santa Fe versions of pin connected trusses were extremely heavily constructed. Parker truss spans emerged in the late 1890s as a suitable alternative for medium to long length truss spans, as the design provided a simple, cost effective and durable structure. Overall, the bridge appears to be in fair to good condition, and continues to be heavily used. The author has ranked this bridge as being regionally significant, due to the design of truss. Relatively few Parker through truss spans remain in use in Illinois.