Cheese Country Trail - Pecatonica River Bridge #8

Located west of Browntown, this unique through truss bridge carries the former Chicago, Milwaukee, St. Paul & Pacific Railroad (Milwaukee Road) Mineral Point Division across the Pecatonica River along Wisconsin Highway 11. The first bridge at this location was constructed in 1880, and consisted of a pair of wooden Howe through truss spans, set onto stone substructures and approached by timber pile trestle spans on the east end. Timber truss spans were commonly used by railroads when initially constructing lines, as they were cost effective and could quickly be built. By 1888, the timber truss spans were no longer suitable, and would be replaced by iron truss spans, reusing the stone substructures. In 1931, two additional secondhand iron truss spans were installed on the east end of this bridge to replace a large portion of the timber pile trestle approach, giving the structure its present configuration. Currently, the bridge consists of a short pile trestle approach on the east end, a 121-foot, 7-panel, pin-connected Pratt through truss span with a skewed east end, a 104-foot, 6-panel, pin-connected Pratt through truss span and two 103-foot, 5-panel, pin-connected Pratt through truss spans. The eastern two piers and abutment are constructed of timber piles, while the western two piers and abutment are constructed of stone. O'Hara Brothers originally constructed the stone substructures using stone quarried from an unknown location. A concrete jacket has been added to the westernmost pier, likely to protect the structure from scour. While the trusses use similar designs, the eastern two and western two trusses have a number of differences.

The eastern two truss spans were originally fabricated in 1886 by an unknown contractor, and were installed here in 1931. The eastern span (span #1) is confirmed to have been reused from Bridge #B-256 across the Wisconsin River at Spring Green, Wisconsin, and it is believed that span #2 was also reused from this location. Only one 121-foot skewed span is known to have been constructed using this design. These trusses use a light design, with light built-up members and decorative portal bracing. The top chord and endposts both use built-up beams, with solid plate on the exterior and V-lacing on the interior. The bottom chord is constructed out of a combination of eyebars at the middle panels and built-up V-laced beams at the end two panels on each end. The vertical members are constructed using built-up beams, with solid plates connecting the channels on the interior of the beam and V-lacing on the exterior of the beam. The diagonal members are constructed of iron eyebars, with crash bars constructed out of V-laced beams. The floor uses a typical design, with four plate girder stringers and plate girder floorbeams at the panel points. Both eastern spans use a decorative portal bracing, which was replicated for the iron trusses at the Wisconsin River crossings at Spring Green (Bridge #B-256), Lone Rock (B-260) and Woodman (B-310 and B-314). These portal bracings are comprised of a lattice beam, with decorative iron rosettes at the intersections. In addition, the portal bracing is connected to the endpost by diagonal bars forming the heel bracing. The sway bracing uses a V-laced design, which also is connected to the vertical members by a similar heel bracing. The upper lateral bracing is composed of iron rods, which are looped on the end and pinned to the sway and portal bracing. The lower lateral bracing is constructed of iron bars, which are looped and pinned into the floorbeams.

The western two trusses use a similar but heavier design to the east spans, and were fabricated in 1888 by an unknown contractor. These trusses use a light design, with light built-up members and lattice portal bracing. The top chord and endposts both use built-up beams, with solid plate on the exterior and V-lacing on the interior. The bottom chord is constructed out of built-up V-laced beams. The vertical members are constructed using built-up beams, with V-lacing connecting both sides of the channels. The diagonal members are constructed of iron eyebars. Similar to the east spans, the west spans use crash bars which are constructed of two channels connecting by V-lacing. These crash bars are slightly heavier construction than the east spans. The floor uses a typical design, with four plate girder stringers and plate girder floorbeams at the panel points. The outer two stringers are considerably lighter than the inner stringers. Unique to these spans, there are no true end floorbeams. The center stringers are connected by an X-bracing, and a V-laced beam connects the trusses and supports the center stringer. The portals are constructed of a lattice beam, which is supported by rounded heel bracing. The sway bracing uses a V-laced design, which also is connected to the vertical members by a angled bars forming heel bracing. The upper lateral bracing is composed of square iron bars, which are looped on the end and pinned to the top chord. The lower lateral bracing is constructed of square iron bars, which are also looped and pinned into the bottom chord.

Railroads often reused steel and iron spans, as it provided a cost effective way to upgrade bridges on branch lines without requiring large amounts of new material. During the 1930s, the Milwaukee Road upgraded bridges on numerous main and secondary lines, freeing up secondhand spans for reuse. The Milwaukee Road preferred to reuse spans wherever possible, and continued the practice into the late 20th Century. While it is likely that the trusses were constructed by a bridge company, it is possible that they were fabricated from raw plates by the Milwaukee Road Bridge Shop. There is some evidence that the Milwaukee Road was fabricating their own iron bridge spans in the 1880s and 1890s. Pratt trusses were the most popular truss bridge design in the second half of the 19th Century, as the pattern provided a simple, cost effective and strong design. This design was primarily used for short to medium sized truss spans, and was superseded by riveted Warren trusses in the early 20th Century. Because this design was commonly used, a number of different ways of constructing this design was used, as evidenced by the differences between the two sets of spans. Since the 1931 construction, the bridge has seen no major alterations. Since abandonment, a concrete deck has been added and steel plate railings installed. The bridge now serves the Cheese Country Trail, a popular ATV/UTV/snowmobile trail. Overall, the bridge appears to be in fair to good condition, with no significant deterioration noted. While the iron superstructure and the stone substructures appear to be in very good condition, the timber approaches appear to be showing some deterioration. While the issues with the timber do not appear to be critical, it is hoped that the timber will eventually be upgraded with new steel piles, retaining the configuration of the bridge and preserving it for years to come. The author has ranked this bridge as being regionally significant, due to the age, truss design and unknown builders.