Barker-Stewart Island Railroad Bridge (North)

Located at the northwest corner of Barker-Stewart Island in Wausau, this unusual through truss bridge carries a former Chicago & North Western Railway spur over the west channel of the Wisconsin River. In the 19th Century, Barker-Stewart Island served as an important industrial hub for the City of Wausau, and was one of the main places where pulpwood floating down the Wisconsin River was intercepted and loaded onto railroad cars. A spur of the Milwaukee, Lake Shore & Western Railway was originally built between present-day Washington Street and the center of the island in 1881. The following year, the line was extended north and west, and a new wooden bridge constructed across the west channel of the Wisconsin River. This first bridge likely consisted of a wooden truss bridge, set onto steel cylinder substructures. In 1911, it was decided to rebuild the bridge with secondhand iron truss spans. On July 23, 1912; a destructive flood struck Wausau, and many of the bridges in the area were destroyed. The bridge at this location was completely collapsed, with the outer spans shoved downstream and the center span completely sunk to the bottom of the river. Clean up from the flood began in the fall, and a contract was awarded to the Adolph Green Construction Company in November 1912 to salvage the bridge and construct new concrete substructures. Large pile drivers, derricks and engines were used to lift the two outer spans out of the river, while a massive plate girder span was ordered to replace the center span. Construction of new substructures continued into 1913; and the present bridge was completed in September 1913. It is reported that the wreckage of the original center span continues to sit at the bottom of the Wisconsin River today.

Currently, the bridge consists of a 160-foot riveted quadrangular lattice through truss east span, a 110-foot through plate girder center span and a 110-foot riveted quadrangular lattice through truss west span, set onto concrete substructures and constructed with a heavy curve at the west end. The east span originally was fabricated in 1888 by the Lassig Bridge & Iron Works, and was used at an unknown location before being relocated here in 1911. The center span was fabricated in 1913 by the American Bridge Company, and was ordered specifically for this structure. The west span originally was fabricated in c. 1882 by an unknown company, and was originally used at an unknown location before being moved here in 1911. The original center span used a design identical to the west span. The present center span uses a standard design, with heavy girders, a traditionally composed floor and square girder ends. While the east and west spans both use a similar design, they are rather different, and represent developments to the quadrangular lattice design through the 1880s.

The east span uses a typical design for this type of truss typically seen in the mid to late 1880s. Features of this span include heavy members, a traditionally composed floor and a flat-top lattice portal bracing with a solid plate in the middle and decorative heel bracings. The top chord of the span uses a heavy channel design, while the bottom chord uses a lighter design consisting of two parallel T-shaped beams. The endposts are constructed of two channels, connected by a solid plate on the outside and an X-lattice on the back side. Diagonal members of the truss are composed of solid rolled beams, lighter channels and built-up beams with tight V-lacing. The upper lateral bracing and lower bracing are composed of narrow iron beams, which are slotted to allow the "X" shape to fit into itself. The portal bracing uses a typical design seen between 1885 and 1890, with a flat lattice portal, which is divided by a plate. The heel bracing consists of an angular plate, with three decorative circular cutouts. The floor is likely composed of a typical design, with two plate girder stringers and floorbeams placed at the panel points. The use of wrought iron, a lengthy span and heavy members likely indicates this span was originally constructed for mainline use. During this era, significant improvements were made to the Galena Division and the Iowa Division, which may shed clues on where this span came from.

The west span uses a somewhat unusual variation of this design, which appears to have been constructed in the early 1880s. Features of this span include lighter members, a traditionally composed floor and an early variation of the pedimented portal bracing that became the standard for the Lassig Bridge & Iron Works later in the 1880s. In addition, the truss webs of this span are considerably shorter than the east span webs, giving the bridge an unusual appearance. The top chord of the span uses a light channel design, while the bottom chord uses a similar design consisting of two parallel T-shaped beams. The endposts are constructed of two channels, connected by a well spaced plates. Diagonal members of the truss are composed light channels and built-up beams with a tight X-lacing. The upper lateral bracing and lower bracing are composed of narrow iron beams, which are offset to allow the "X" shape to fit over itself. The portal bracing uses an early variation of a pedeimented design, with a thin lattice beam, divided by a wide plate in the center. Heel bracing consists of a solid bar, riveted to the endposts and to the portal bracing. The floor is composed of a typical design, with two stringers and floorbeams placed at the panel points. It is unknown if this span has been modified since it was initially fabricated. Modifications could include the replacement of the original floor or revisions to the portal bracing. The span is also considerably wider than the east span, possibly indicating it was initially a double track span, or modified to serve the curve the bridge is located on. While a builder is unknown, these spans were built almost exclusively by the Leighton Bridge & Iron Works between the late 1870s and 1881; followed by the Alden and Lassig Bridge & Iron Works between 1881 and 1886. The use of a wrought iron span in the early 1880s likely indicates that this bridge was originally constructed for mainline use, although there is no clear location where it may have come from. One possible location is the Ford River Bridge west of Escanaba, Michigan; which was originally constructed of two 110-foot lattice truss spans and replaced in 1910.

Lattice truss designs are 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). This design was initially perfected in the late 1870s, and the first generation of spans were mostly produced by the Leighton Bridge & Iron Works. The first generation of spans constructed for the C&NW featured an arched and pedimented lattice portal bracing, light sway bracing and laced members. After the Leighton Bridge & Iron Works closed, the shops were sold to the Alden and Lassig Bridge & Iron Works, which continued producing a variant of the first generation of spans with a slightly different portal. The second generation was nearly exclusively constructed by Lassig Bridge & Iron Works between 1884 and 1900, and featured heavier members and a heavier portal bracing. Early spans from this generation included a flat lattice portal and decorative cutouts, while later spans had a pedimented lattice portal with similar cutouts. 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. 19th Century versions of this design were primarily constructed out of iron, while 20th Century versions of this design used much heavier members and were constructed of steel. The C&NW preferred this design, as it was both strong and demonstrated great resilience in case of a derailment. The eastern 160-foot span and the center 110-foot span both represent bridge spans pushed to the limits of their design during the era they were constructed. Currently, the bridge is out of service, with no customers remaining on the spur. While its future is uncertain, it is hoped that the bridge can possibly be reused as a trail bridge in the future, preserving the history for generations to come. Overall, the bridge appears to be in fair to good condition, with no significant deterioration noted. The author has ranked this bridge as being highly significant, due to the unique variety of span designs, ages and lengths.