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| Name | Great River State Trail - Black River Bridge Chicago & North Western Railway Bridge #673 |
| Built By | Chicago & North Western Railway |
| Currently Owned By | Wisconsin Department of Natural Resources |
| Superstructure Contractor | American Bridge Company of New York |
| Substructure Contractors | Unknown |
| Length | 1220 Feet Total, 140 Foot Main Spans |
| Width | 1 Track |
| Height Above Ground | 20 Feet (Estimated) |
| Superstructure Design | Warren Through Truss, Deck Plate Girder and Timber Pile Trestle |
| Substructure Design | Stone Masonry, Concrete and Timber Pile |
| Date Built | 1913 (Deck Girders) 1927 (Truss Spans) |
| Traffic Count | 0 Trains/Day (Bridge is Open to Pedestrian Traffic) |
| Current Status | Open to Pedestrian Traffic |
| Chicago & North Western Railway Bridge Number | 673 |
| Significance | Moderate Significance |
| Documentation Date | 11/23/2013 |
In 1860, the Beloit and Madison Railroad (B&M) constructed 17 miles of railroad, extending from Beloit, Wisconsin to Magnolia, Wisconsin. In 1864, the B&M constructed an additional 32 miles of railroad, extending from Magnolia to Madison, Wisconsin. In 1864, the Madison, Lodi and Baraboo Railroad (ML&B) began grading for a new railroad line, extending from Baraboo, Wisconsin to Merrimac, Wisconsin. The ML&B was acquired by the Baraboo Air Line Railroad (BAL) in 1870, and began construction on a line extending from Reedsburg, Wisconsin to Madison. In 1870, the La Crosse, Trempealeau and Prescott Railroad (LCT&P) constructed an additional 29 miles of railroad, extending from the Winona & St. Peter Railroad (W&StP) at Winona, Minnesota to the north side of La Crosse, Wisconsin; constructing a large bridge across the Mississippi River. The BA&L and the B&M were acquired by the Chicago & North Western Railway (C&NW) in 1871. The C&NW continued construction, eventually opening a 129 mile line between Madison and present-day Medary on the north side of La Crosse in 1873. This line was difficult to construct, as it crossed through areas of rugged terrain, requiring three tunnels and numerous wooden trestles. The LCT&P was purchased by the C&NW in 1876.
Soon after completion, this line became an important route for the C&NW. The line connected an existing mainline to Chicago with the existing W&StP mainline across southern Minnesota. In addition, the Chicago, St. Paul, Minneapolis & Omaha Railway (Omaha Road, a C&NW subsidiary) mainline ended at this line in Elroy, Wisconsin, providing the C&NW with a connection to the Twin Cities. Numerous improvements were made in the late 1870s and throughout the 1880s, including filling wooden trestles and replacing wooden bridges with iron and stone. The C&NW constructed a short 4-mile branch line from Medary to La Crosse in 1886. By the late 19th Century, traffic over this route had grown to the point that a second track was necessary. Between 1896 and 1899, the C&NW completed a second track between Evansville, Wisconsin and Elroy. By the early 20th Century, the C&NW was operating an expansive railroad network throughout the Midwest, radiating north and west from Chicago. This line initially served as one of the principal mainlines of the railroad, connecting Chicago to the Twin Cities and the mainline to South Dakota.
Between 1910 and 1912, the C&NW undertook a large construction program to construct shorter routes and streamline operations. A cutoff between Milwaukee and Sparta opened in 1911, reducing the importance of this line. Between 1953 and 1956, much of the double track would be removed. A portion of the line was abandoned between Elroy and Sparta in 1964, and became one of the United States first rail-trail projects. In 1978, the Sparta to Medary and Winona to Trempeleau, Wisconsin segments would be abandoned, followed by the Beloit to Evansville segment in 1979 and the Medary to Trempeleau and La Crosse segments in 1981. The Reedsburg to Elroy segment was abandoned in 1987. All of the line west of Reedsburg would be acquired by the Wisconsin Department of Natural Resources for trail use.
In 1995, the C&NW would be purchased by Union Pacific Railroad (UP). In 1996, UP leased the Fitchburg to Reedsburg segment to the Wisconsin & Southern Railroad (WSOR). In addition, UP attempted to abandon the Evansville to Fitchburg segment the same year. In response to possibly losing railroad service, the communities of Fitchburg and Oregon purchased the line, although it was out of service. In 2014, the State of Wisconsin acquired the Fitchburg to Reedsburg line, and contionued to lease it to WSOR. The same year, WSOR began operations over the Oregon to Fitchburg line, while the Evansville to Oregon segment remains out of service. Today, WSOR operates the Reedsburg Subdivision between Madison and Reedsburg. The 400 State Trail uses the former railroad between Reedsburg and Elroy; the Elroy-Sparta State Trail uses the former railroad between Elroy and Sparta; the La Crosse River State Trail uses the former railroad between Sparta and La Crosse; and the Great River State Trail uses the former line between Medary and Marshland.
Located near the former railroad station of Lytles, this large through truss bridge carries the former Chicago & North Western Railway over the Black River alongside the former Chicago, Burlington & Quincy Railroad bridge. The first bridge at this location was likely a timber truss bridge with lengthy timber pile trestle approaches, constructed when the line was first built. During the 1880s, the C&NW invested significant capital into upgrading this line, replacing wooden bridges with stone and iron structures. In 1886, the original bridge would be replaced with a pair of 140-foot riveted quadrangular lattice through truss spans, set onto timber pile piers. This design of span was standard for the C&NW, and was likely fabricated by the Lassig Bridge & Iron Works. Permanent stone piers and a south abutment were constructed under the truss spans in 1892. Further work included the addition of three deck girder spans to the north approach in 1913. After the southernmost pier was damaged in 1919, the pier was replaced by a concrete structure in early 1920. By the late 1920s, many of these early iron truss spans had become too light for traffic, and required replacement. The main truss spans were replaced by heavier steel spans in 1927, giving the bridge its present configuration. It is unknown if the old truss spans were reused elsewhere after replacement.
Currently, the bridge consists of a pair of 140-foot, 6-panel, riveted Warren through truss spans, approached by a lengthy timber pile trestle approach. This approach is broken up with three 30-foot deck plate girder spans set over a swampy area. The bridge is set onto a combination of stone, concrete and timber pile substructures. The truss spans use a typical design for the era, with heavily constructed members and a standard floor system. The top chords and endposts are constructed of built-up members, which are made of channels connected by an X-lacing and covered on top with a steel plate. The bottom chord is comprised of two parallel channels, connected by narrow plates. The vertical members and some diagonals use solid rolled beams, while other diagonal members use a built-up design consisting of heavy V-laced channels. The portal and sway bracing both use an A-frame design, with the struts at the top of the sway bracing using a lattice beam. Typical of spans from this era, the floorbeams and stringers are both composed of heavy plate girders. Typical of shallow deck girder spans, each of the deck girder spans uses four girder lines and minimal external stiffeners. American Bridge Company fabricated both the truss and girder spans. Unusual to the girders, a rectangular builders plaque was used. This type of plaque was discontinued around 1910. Railroad records indicate that the deck girder spans were constructed at the Detroit plant of the American Bridge Company, which may have used this plaque design after 1910.
When the present bridge was constructed, the south abutment and north pier were reconstructed by adding concrete caps, likely to raise the elevation of the bridge. Stone for the original piers was quarried at an unknown location, and uses a brownish color, typical of stone seen on the Madison Division of the C&NW. An unknown contractor constructed the original stone substructures, while additional unknown contractors constructed the concrete south pier and concrete additions to the stone north pier and abutment. Warren trusses became popular in the 20th Century, as they were durable, simple and economical. This design was also among the first to use riveted connections extensively, which railroads preferred by the 20th Century. Deck girder spans were also popular for railroad use, as they were durable and easy to construct. Currently, the bridge serves the Great River State Trail; and a wooden deck and railings have been added to the bridge. 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.
Citations
| Build dates | Chicago & North Western Valuation Notes at the Chicago & North Western Historical Society Archives |
| Builder (superstructure) | Missing American Bridge Company plaque |
| Railroad History Citation | ICC Valuation Information, Compiled by Richard S. Steele |