UP Sheboygan River Bridge (West)

Located on the west side of Sheboygan, this through truss bridge carries a former Chicago & North Western Railway branch line over the Sheboygan River. It is believed that the first bridge at this location was a timber pile trestle, constructed when the line was first built. In the late 1880s and early 1890s, the C&NW invested significant capital into this line, replacing timber pile trestle bridges with stone, iron and heavier combination bridges. In 1890, the original bridge was replaced by a 155-foot combination Howe through truss bridge, set onto stone abutments. Combination spans were unique for using timber compression members and iron tension members. These spans were often designed with a lifespan of 10 years or less. By the turn of the 20th Century, the combination bridge had become too light for traffic, and would be replaced by the present steel through truss bridge, reusing the stone abutments. Currently, the bridge consists of a 155-foot, riveted quadrangular lattice through truss span, set onto stone abutments. The truss span uses a standard design for the era, with built-up members and a traditionally composed floor. The top chord and endpost both use a built-up design, consisting of V-lacing on the bottom and solid plates on the top. The bottom chord uses a similar design, and is composed of V-lacing on the bottom only. The diagonal members use a combination of tightly V-laced beams, solid bars connected by thin plates and solid bars which are not connected to each other. Similar to other spans from this era, the floor is composed of plate girder floorbeams, two plate girder stringers and solid bars for the lower lateral bracing. Also similar to spans from this era, the portal bracing uses an A-frame design and is composed exclusively of V-laced beams. The sway bracing also uses V-laced beams; while the upper lateral bracing is composed of steel bars. The abutments use a standard design, with stepped wing walls extending diagonally from the bridge. Stone for the abutments is composed of a white limestone, likely quarried at the C&NW quarry at Duck Creek, Wisconsin. An unknown contractor fabricated the superstructure, and an additional unknown contractor constructed the abutments.

This type of truss design is relatively uncommon throughout the United States. However, a few railroads preferred the design, such as the Chicago, Rock Island & Pacific Railway (Rock Island), the Chicago & North Western Railway (C&NW) and the Chicago, St. Paul, Minneapolis & Omaha Railway (Omaha Road). Spans constructed in the early 1880s for the C&NW featured an arched and pedimented lattice portal bracing, light sway bracing and laced members. The second generation was nearly exclusively constructed by Lassig Bridge & Iron Works between 1884 and 1900, and featured heavier members and a pedimented portal bracing. Later designs featured even heavier members and an A-frame portal bracing. While the design fell out of favor for the Rock Island and Omaha Road around the turn of the 20th Century, the design remained popular with the C&NW into the 1920s. This particular span uses a design typical for the third generation of quadrangular lattice through trusses. Since the initial construction, the bridge has seen no significant alterations, and remains in occasional use. 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.