UP Red Cedar River Bridge

Located alongside Interstate 94 on the north side of Menomonie, this large deck truss bridge carries the former Chicago, St. Paul, Minneapolis & Omaha Railway mainline over the Red Cedar River. The first bridge at this location was set onto an alignment slightly north of the present structure, and consisted of two wooden Howe deck trusses, set onto stone piers and approached by timber pile trestle spans on either end. In 1879, the bridge would be reconstructed with a new iron bridge, set onto a new alignment slightly further south. This new alignment helped reduce the steep grades and sharp curves approaching the bridge. The iron bridge consisted of two 164-foot, 11-panel, pin-connected Whipple deck trusses, approached by a 40-foot lattice deck truss span on the east end and a 60-foot lattice deck truss span on the west end. The entire bridge was set onto stone piers, and built by unknown contractors. The trusses were heavily constructed for the era, with unusually large top chords and endposts. In 1897, the bridge was strengthened, and the approach spans replaced with new deck girder spans.

By the early 20th Century, traffic using this line had significantly increased, and it was desired to construct a second track. The present double track bridge was constructed on a new alignment in 1912. During the construction of the present bridge, the stone substructures from the first bridge were removed, and the second bridge was removed shortly after completion. The bridge consists of two large 160-foot, 6-panel, pin-connected Pratt deck truss spans, approached by an 80-foot deck plate girder span on either end. The entire bridge is set onto stone substructures, which are constructed of limestone quarried at Mankato, Minnesota. American Bridge Company fabricated the superstructure, while the Bates & Rogers Construction Company constructed the substructures. While simply designed, the truss spans are heavily constructed, intended to carry heavy mainline traffic. The bottom chord is constructed using traditionally composed eyebars, with two sets for each truss line at the end panels and three sets at the inside panels. The vertical members, top chords and endposts are all constructed using heavily laced members, which are composed of an X-lacing instead of a more traditional V-lacing. The lower lateral bracing is constructed using two parallel beams with V-lacing, and the interior bracing of the truss is simply constructed with slender members connecting opposite lower and upper connections to form an "X". The floorbeams of the bridge are particularly large, using large steel plates. Each track uses two large girders for stringers, arranged into two sets of two. The deck girder spans are traditionally composed, using heavy girders and an open deck.

Through much of the late 19th Century, the Omaha Road used lattice truss spans instead of more traditionally constructed single intersection designs. While stronger than traditional designs, lattice trusses were statically indeterminate, and required significantly more material. Pin connected truss spans had fallen out of popularity in the first years of the 20th Century. While pin-connected Pratt trusses dominated railroad truss bridge design at the end of the 19th Century, this design was superseded by riveted Warren spans, which provided greater rigidity and strength. The use of pin-connected Pratt trusses is unusual for this era, particularly on a heavily constructed mainline bridge. It is possible this design was chosen due to the simplicity or proven strength for double track spans. Because the pin-connected Pratt design had fallen out of favor, the truss spans on this bridge are among the latest known single intersection pin-connected truss spans constructed for railroad use in the Midwest. The bridge has seen few alterations since it was first completed, although only the south track is in use. Overall, the bridge appears to be in fair to good condition, and appears to be well maintained with minimal deterioration. The bridge is highly visible to vehicles traveling on Interstate 94, and the stone substructures from the previous bridge are also visible. The author has ranked this bridge as being regionally significant, due to the truss design, age and late use of a standard 19th Century design.