WSOR Rock River Bridge (Mayville)

In 1865, the Iron Ridge and Mayville Railroad (IR&M) began grading a new railroad line, extending from the existing La Crosse & Milwaukee Railroad (LC&M) line at Iron Ridge to Mayville, approximately 7 miles north.  In 1874, the Fond du Lac, Amboy & Peoria Railway (FdLA&P) was charted to construct a 3-foot narrow gauge line between Fond du Lac, Wisconsin and Amboy, Illinois.  Construction on the railroad began in 1875, and in 1876, the railroad reached the existing LC&M line at Iron Ridge, Wisconsin using the roadbed graded by the IR&M.  It was decided to cease construction at this location, giving the FdLA&P 29 total miles constructed.  The property of the IR&M was formally purchased by the FdLA&P in 1878.  The FdLA&P was acquired by the Chicago, Milwaukee & St. Paul Railway (Milwaukee Road) in 1883, and was converted to a standard gauge line soon after.  The line became a branch line for the Milwaukee Road, primarily serving industries in Fond du Lac.  In 1890, the Wisconsin Midland Railroad constructed 2 miles of track in Fond du Lac to serve various industries east of the Fond du Lac River.  This railroad was purchased by the Milwaukee Road in 1897.

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. Throughout the 20th Century, financial conditions for the Milwaukee Road continued to deteriorate.  This line began to fall into disrepair, and traffic over the line began to lighten.  The railroad again entered bankruptcy in 1977, and was forced to liquidate unprofitable lines.  The line from Iron Ridge to Mayville was sold to the State of Wisconsin in 1980, which leased it to the Wisconsin & Southern Railroad (WSOR) the same year.  In the early 1980s, the segment between Mayville, Wisconsin and Fond du Lac would be abandoned, with the exception of some short spurs within Fond du Lac.  A portion of the line in Fond du Lac was sold to the Wisconsin Central, Ltd (WC) in 1987.  The WC was purchased by Canadian National Railway in 2001, which continues to operate a short segment in Fond du Lac.  The WSOR continues to operate the segment between Iron Ridge and the south side of Mayville as the Mayville Spur, which primarily serves a handful of industries.