Donovan Railroad Crossing

Located south of Donovan, this unusual viaduct carries the former Chicago, Milwaukee, St. Paul & Pacific Railroad over the former New York Central Railroad and US Route 52. The first bridge at this location was likely a timber pile structure, constructed when the line was built with the intention of being temporary. In 1911, the bridge would be reconstructed with a pony truss and through plate girder spans, set onto concrete substructures. The bridge would retain timber lengthy timber pile trestle approaches. In 1923, the bridge was widened with an identical but inverse set of spans, placed onto the east side of the structure. The bridge was again modified in 1934, when two deck plate girder spans were added to the north end of the bridge to cross US Route 52, and new concrete substructures constructed. In the 1940s or early 1950s, the western track of the bridge would be removed, giving the structure its current configuration.

The southern spans of the bridge consist of a 118-foot, 8-panel riveted Warren pony truss span, approached by two 46-foot through plate girder spans on the east face. The spans are set onto concrete piers and columns, and approached by timber pile trestle spans on the south. These spans utilize an unusual construction, where half of the bridge utilizes a truss, while the other half utilizes a plate girder. The western face of the remaining structure utilizes a configuration of one plate girder on each end of the truss. When initially constructed for two tracks, it appears that the western track was an inverse of the eastern track, with two through girders on the south end of the west face. A middle section of the bridge consists of eight timber pile trestle spans, and the northern section of the bridge consists of two 80-foot deck plate girder spans. The northern substructures utilize concrete piers and abutments, and a transverse girder runs between two concrete columns to form the northernmost pier. All steel spans of the structure were fabricated by American Bridge Company. The substructures of the northern spans were constructed by Thomas McQueen Company, and the southern substructures were constructed by an unknown firm.

The structure utilizes a number of unusual features. The truss span consists of solid I-beam members, which utilize heavy riveted connections and a traditionally composed floor. The through girder spans utilize the same design of floor, but use a shallow design. However, the use of a pony truss and through girder spans to form a continuous structure is unusual, and likely was only done to accommodate the heavy skew of the railroad below. The substructures on the southern portion of the bridge utilize an offset design, which allows for the piers to be placed perpendicular to the bridge span. Pier #5 of the structure utilizes concrete columns, which are spaced on either side of the tracks below. It appears that the piers were constructed in 1911, with the exception of the eastern concrete column, which was constructed in 1923. The northern pier of the bridge also utilizes two concrete columns, which are connected by a steel plate girder, set across the road and perpendicular to the bridge spans. The girder is heavily constructed, with extensive riveting for only two girders. It is possible that the cross girder was constructed of scrap material, supplied by the Milwaukee Road. Piers such as this were used sparingly by railroads, but later became popular in urban areas for roadway use. Overall, the bridge appears to be in fair condition, with significant spalling noted on the concrete substructure. The author has ranked this bridge as being regionally significant, due to the unusual design.