UP Illinois Road Bridge (Lake Forest)

In the early 1850s, several railroad companies began constructing railroad lines radiating from Chicago.  In 1855, the Chicago & Milwaukee Railroad (C&M) constructed a 45-mile railroad line, extending north from an existing railroad line at Ashland Avenue and Armitage Avenue in Chicago to the Wisconsin State Line near Kenosha.  At the same time, the Milwaukee & Chicago Railroad (M&C) constructed an additional 40 miles north to Milwaukee.  The two railroads would be consolidated into a new railroad known as the Chicago & Milwaukee Railroad (C&M) soon after completion, and would come under control of the Chicago & North Western Railway (C&NW) in 1866.  The C&M was leased to the Chicago, Milwaukee and North Western Railway (CM&NW) in 1883.  The C&NW acquired control of the CM&NW soon after.   The C&NW had constructed and acquired a large network of railroad lines through the Midwest.  This line formed a portion of the principal north mainline of the C&NW, eventually extending to northern Wisconsin and the Upper Peninsula of Michigan.  Due to increasing traffic along this line, a second track would be constructed between 1890 and 1892.

In the late 19th Century, railroad traffic had become a significant safety hazard for the City of Chicago.  A solution was devised to elevate the railroad tracks throughout the city, placing the railroads upon embankments and constructing subways at each street.  In 1898, the C&NW completed track elevation and a third track from Ashland Avenue to Balmoral Avenue; followed by Balmoral Avenue into Evanston between 1907 and 1910.  The C&NW would become a prominent railroad in the Midwest, eventually building a system over 11,000 miles long.  Throughout the 20th Century, this line would continue to be an integral part of the C&NW system.  The second track would be removed north of Kenosha after 1959.  In 1995, the C&NW would be purchased by the Union Pacific Railroad.  Union Pacific continues to operate the route as the Kenosha Subdivision.  Metra operates a commuter service, the Union Pacific-North Line over the Chicago to Kenosha section.