BNSF E. Branch DuPage River Bridge

<P>During the 1850s, the Chicago, Burlington & Quincy Railroad (CB&Q) was beginning to construct a railroad network throughout northern Illinois.  Lines extending west from Aurora utilized a short branch to West Chicago to reach the Galena & Chicago Union Railroad, where the railroad had trackage rights into Chicago.  This operation was unsatisfactory to the CB&Q, which desired a direct route into Chicago, which was quickly becoming the major railroad hub in the central United States.  Construction began in 1862, progressing westwards from the Chicago River, where it connected to the St. Charles Airline to reach Union Station.  The railroad reached a point west of Harlem, and would discontinue construction.  Work resumed in 1872, with the route between Chicago and Aurora completed that year.  This route provided a significant link for the CB&Q, and significantly improved operations.  The line quickly became the principal mainline of the CB&Q, becoming known as the "racetrack" due to the volume of trains running between Chicago and Aurora.  Because of the importance of this line, the route was initially constructed with two tracks.  A third track would be constructed from Chicago to Belmont in 1887, with a fourth track constructed within Chicago in 1893.  Like nearly all railroads within Chicago, the route was elevated and placed on retaining walls between the late 1890s and early 1900s.  Additional tracks were added during this time.  Further improvements were made in 1914, when a third track was added from Belmont to Eola.  In 1922, a new elevated cutoff was constructed from Eola to the west side of Aurora, which provided three tracks.  Throughout the 20th Century, the line continued to serve as the principal mainline of the CB&Q.  In 1970, the CB&Q was merged with the Northern Pacific Railway and the Great Northern Railway to form Burlington Northern Railroad (BN).  The Regional Transportation Authority (RTA) began subsidizing commuter operations within Chicago and the suburbs in 1974, eventually taking control of operations as Metra in 1985.  In 1996, BN merged with Atchison, Topeka & Santa Fe Railway to form BNSF Railway.  BNSF currently operates the line as the Chicago Subdivision, and it remains among the busiest lines within the Chicago area.  Metra continues to operate over this route between the Chicago Union Station and Aurora as the BNSF Line.