| Name | WSOR Milwaukee River Bridge (Saukville) Chicago, Milwaukee & St. Paul Railway Bridge #U-52 |
| Built By | Chicago, Milwaukee & St. Paul Railway |
| Currently Owned By | State of Wisconsin (Operated by Wisconsin & Southern Railroad) |
| Superstructure Contractor | American Bridge Company of New York |
| Length | 234 Feet Total, 117 Foot Spans |
| Width | 1 Track |
| Height Above Ground | 15 Feet (Estimated) |
| Superstructure Design | Pratt Pony Truss |
| Substructure Design | Concrete |
| Date Built | 1902 |
| Traffic Count | 1 Train/Day (Estimated) |
| Current Status | In Use |
| Chicago, Milwaukee & St. Paul Railway Bridge Number | U-52 |
| Wisconsin & Southern Railroad Bridge Number | U-52 |
| Significance | Moderate Significance |
| Documentation Date | 8/6/2016 |
In 1870, the Milwaukee & Northern Railway (M&N) was charted to construct a railroad line between Milwaukee, Wisconsin and the Upper Peninsula of Michigan. Construction began the same year, and by the end of 1870, 13 miles had been constructed to Cedarburg, Wisconsin. In 1872, the railroad extended an additional 73 miles to Hilbert Junction, Wisconsin, and also constructed a branch line to Meshasha, Wisconsin. In 1873, an additional 27 miles would be completed to Green Bay. In 1874, the M&N completed a bridge across the Fox River, reaching Fort Howard, Wisconsin. In 1880, the M&N acquired the Ontonagon & Brule River Railroad (O&BR), which was planning a line through the Upper Peninsula of Michigan. In 1881, the O&BR constructed 20 miles between Rockland, Michigan and Ontonagon, Michigan. An additional 24 miles of track would be constructed by the M&N the same year, reaching a point near Stiles, Wisconsin. The following year, an additional 15 miles would be constructed to near Coleman, Wisconsin; followed by 22 more miles to Wausaukee, Wisconsin in 1883. In 1884, 10 more miles of track were completed to Amberg, Wisconsin, followed by an additional 20 miles to the Menominee River in 1886. In 1887, the M&N extended an additional 58 miles to Champion, Michigan. Between 1888 and 1889, the M&N extended to Sidnaw, Michigan; and in 1889, the O&BR extended an additional 26 miles from Rockland to Sidnaw to complete the line. The following year, the O&BR was fully absorbed by the M&N. In 1893, the M&N was acquired by the Chicago, Milwaukee & St. Paul Railway (Milwaukee Road).
This line quickly became a mainline for the Milwaukee Road, connecting Lake Superior to Milwaukee, and serving valuable metal deposits in the Upper Peninsula of Michigan. Throughout the late 19th and early 20th Century, the Milwaukee Road greatly expanded throughout the Midwest, acquiring and constructing numerous lines. By the early 20th Century, the Milwaukee Road was among the largest railroads in the United States, operating a network of railroad lines over 10,000 miles in length. The Milwaukee Road was often in financial trouble, especially after the costly Pacific Extension was completed in 1909. In 1925, the company declared bankruptcy, and reorganized as the Chicago, Milwaukee, St. Paul and Pacific Railroad in 1928. The railroad remained afloat through much of the 20th Century, although it remained in financial trouble. The railroad again entered bankruptcy in 1977 and was forced to liquidate unprofitable lines. In 1980, the Escanaba & Lake Superior Railroad (E&LS) purchased the line between Iron Mountain, Michigan; followed by the E&LS acquiring the Iron Mountain to Green Bay segment as part of a lease-to-own agreement in 1982. The State of Michigan and the State of Wisconsin both invested significant capital into upgrading the route, including replacing rail and ties.
By 1985, a suitor for the Milwaukee Road was being sought, and the Soo Line Railroad, controlled by Canadian Pacific Railway (CP) purchased the Milwaukee Road in 1986. A connection between the Chicago & North Western Railway (C&NW) and the E&LS was created at Howard, Wisconsin the same year, allowing the E&LS to discontinue use of the line between Howard and Green Bay. In 1987, the Milwaukee to Green Bay segment was sold to the Wisconsin Central, Ltd. (WC). The WC was formed to purchase a number of secondary routes in eastern Wisconsin from the Soo Line, which included Soo Line and former Milwaukee Road trackage. A portion of the route between Greenleaf and Green Bay was abandoned in approximately 2000, followed by the segment between Hilbert and Greenleaf in 2001. In 2001, the WC was purchased by Canadian National Railway. The E&LS abandoned a segment between Rockland and Ontonagon in 2009. In approximately 2004, the State of Wisconsin acquired a segment of line between Saukville, Wisconsin and Kiel, Wisconsin; and leased it to the Wisconsin & Southern Railroad (WSOR). The line between North Milwaukee and Saukville was purchased by the WSOR in 2015. Today, WSOR operates the North Milwaukee to Kiel segment as the Plymouth Subdivision; and CN operates the Hilbert to Kiel segment. A portion of the line from Hilbert to Green Bay is part of the Fox River Trail; and a segment from Rockland to Ontonagon is also used as a trail.
Located north of Saukville, this pony truss bridge carries the former Chicago, Milwaukee, St. Paul & Pacific Railroad (Milwaukee Road) mainline across the Milwaukee River. The first bridge at this location was likely a timber pile trestle bridge, constructed when the line was first built. In 1891, the bridge was rebuilt with two 111-foot wooden Howe through truss spans, approached by timber pile trestle spans. By the turn of the 20th Century, wooden truss bridges had largely become obsolete for railroad use. In 1902, the timber bridge was replaced by the present pony truss bridge. Currently, the bridge consists of two 117-foot, 6-panel, pin-connected Pratt pony truss spans, set onto concrete substructures. The superstructure uses a standard Milwaukee Road pony truss design, which was replicated at numerous points throughout the system. Typical of this design, the spans are heavily constructed, using large built-up members. The top chord and endposts are constructed of built-up beams, with X-lacing on the bottom and a solid plate on the top. Similarly, the bottom chord is constructed of built-up beams with X-lacing on both sides. The vertical members are composed of large rolled beams, which are connected to the floorbeams with large triangular plates. The diagonal members are composed of steel bars, with the members in the center panels using turnbuckles. The floor was specially constructed for this bridge to allow for heavy ore-car loading. The floor is constructed of two heavy plate girder stringers and plate girder floorbeams placed at the panel points.
The Milwaukee Road was somewhat unique, as most spans were designed in-house. By using standard spans, steel spans could easily be repaired or reused. These spans were ordered in June 1901 as part of a large order of 117-foot pony truss spans. Based on plaques identified on other bridges from the same order, it is believed that this bridge was fabricated by American Bridge Company. The concrete substructures were constructed by labor employed by the Milwaukee Road Bridge & Building Department. Pratt trusses were arguably the most popular truss bridge design in the second half of the 19th Century, as they were simple, durable and strong. This particular pony truss design was used extensively by the Milwaukee Road between approximately 1895 and 1905. Several different standard sizes were used, mainly ranging between 95 feet and 120 feet. By the early 20th Century, many railroads were moving away from using pin connected spans. The Milwaukee Road switched to using riveted Warren pony truss spans in approximately 1905. Since the initial construction, the bridge has seen no significant alterations, and remains in regular 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.
Citations
| Build date | Milwaukee Road Drawing Collection, located at the Milwaukee Road Archives at the Milwaukee Public Library |
| Builder | Based on identical spans ordered on the same date |
| Railroad History Citation | ICC Valuation Information, Compiled by Richard S. Steele |