UP Rock River Bridge (Jefferson)

In 1854, the Rock River Valley Union Railroad Company (RRVU) constructed 18 miles of new railroad, extending from Chester, Wisconsin to Fond du Lac, Wisconsin.  In 1855, the railroad began construction on an additional 11 miles, prior to being consolidated into the Chicago, St. Paul and Fond du Lac Railroad (CStP&FdL) early that year.  The CStP&FdL completed the 11 miles south to Minnesota Junction, Wisconsin (present-day Clyman Junction) in 1855.  The CStP&FdL was sold to the Chicago & North Western Railway (C&NW) in 1859.  The C&NW constructed an additional 57 miles of railroad between Janesville, Wisconsin and Minnesota Junction in 1859.  The same year, the C&NW completed 17 additional miles between Fond du Lac and Oshkosh, Wisconsin; followed by 20 miles between Oshkosh and Appleton, Wisconsin in 1861 and an additional 28 miles between Appleton and Green Bay, Wisconsin in 1862.  The C&NW was reorganized in 1864, and the line would be extended north into Michigan in the 1860s and early 1870s.

During the second half of the 20th Century, the C&NW had constructed and acquired a large amount of trackage throughout the Midwest.  By the 20th Century, the C&NW was operating an extensive railroad network, which radiated north and west from Chicago.  This line served as a mainline, connecting the mainline at Janesville to industrial areas along Lake Winnebago and to Lake Michigan at Green Bay.  While the line served as a mainline, it was one of two parallel routes between southern Wisconsin and Green Bay, with the other line following the shore of Lake Michigan north from Milwaukee.  By the late 20th Century, the C&NW had begun to consolidate operations and abandon excess lines to remain a profitable railroad.  The line between Clyman Junction and Fond du Lac would be abandoned in 1985, and purchased for trail use.  

In 1988, the C&NW sold the Fond du Lac to Green Bay segment of this line to the Fox River Valley Railroad, which became the Fox Valley and Western Ltd. (FV&W) in 1993.  The FV&W was a subsidiary of the successful Wisconsin Central Ltd. (WC), which had acquired a large amount of former Milwaukee Road and Soo Line trackage in Wisconsin.  The C&NW was purchased by Union Pacific Railroad (UP) in 1995.  The segment between Janesville and Fort Atkinson, Wisconsin would be abandoned in 1998, and portions acquired for trail use.  Portions of the line between Oshkosh and Neenah were also abandoned in the late 1990s.  In 2001, WC was purchased by Canadian National Railway (CN), and became the American subsidiary of the railroad.  After CN acquired the line, portions of the line in Fond du Lac were abandoned in 2003, and the Fond du Lac to Oshkosh segment would be heavily rebuilt.  Today, the Fond du Lac to Clyman Junction segment is used as part of the Wild Goose State Trail, and portions near Fort Atkinson and Neenah are also used by trails.  UP operates the Clyman Junction to Fort Atkinson segment as the Clyman Industrial Lead, and CN operates the North Fond du Lac to Green Bay segment as the Fox River Subdivision.