The Northwestern Elevated Railroad Company was granted a 50-year franchise by the City of Chicago in 1894. Construction began in early 1896, but ceased in 1897. A train was ran December 31st, 1899 to meet franchise requirements, but was declared unsafe.
After a new franchise was granted, a 6.41 mile segment of railroad opened in early 1900 between Wilson Avenue and the Loop.
In 1904, the Northwestern Elevated came to an agreement with the Milwaukee Road to use tracks between Wilson Avenue and Evanston.
In 1907, the plan was officially approved. The railroad began construction of elevation through Evanston in 1908, which was completed in 1910. The elevation between Lawrence Avenue and Howard Street began in 1914 and was complete by 1922.
In early 1919, a series of agreements allowed the Chicago, North Shore & Milwaukee to use the tracks.
By 1924, the Northwestern Elevated Railroad became part of the Chicago Rapid Transit Company. An elevation of the remaining segment north of University Place in Evanston was completed in 1931.
In 1947, the CRT became part of the Chicago Transit Authority. After the CNSM folded in 1963, the CTA purchased the entire line north of Wilson Avenue.
Currently, the line between Howard Street and Wilmette is the CTA Purple Line and the line south of Howard Street is the CTA Red Line.
06/26/21
Located in Evanston, this concrete slab bridge carries the CTA Purple Line over Colfax Street.
Built during 1930-1931, this bridge features dual single track bridges, each with four spans of concrete slab set onto concrete substructures.
Concrete structures like this are very common for track elevations after 1915. While the dual tracks are different superstructures, they share the same abutments. These abutments are capable of expanding to four tracks.
Overall, the bridge appears to be in good condition. Little serious deterioration was noted on the bridge.
The author has ranked the bridge as being minimally significant, due to the common design.
The photo above is an overview.