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Lake Street Bridge

Through Truss Bascule Bridge over Chicago River
Chicago Loop, Chicago, Cook County, Illinois

Click the Photo Above to See All Photos of This Bridge!
Name Lake Street Bridge
Built By City of Chicago
Contractor Ketler-Elliot Company of Chicago, Illinois
Currently Owned By City of Chicago
Railroad Feature Carried CTA Green Line
Railroad Spans Length 455 Feet Total, 245 Foot Lift Span
Roadway Spans Length 333 Feet Total, 245 Foot Lift Span
Width 2 Tracks, 2 Traffic Lanes
Height Above Ground 16 Feet (Estimated)
Superstructure Type Warren Through Truss and Warren Pony Truss
Substructure Type Concrete
Date Built 1916
Date Rehabilitated 1995
Traffic Count 150 Trains/Day (Estimated)
Current Status In Use
Significance High Significance
Documentation Date June 2015
In 1895, the Northwestern Elevated Railroad (The Northwestern "L") began charting an electrified elevated line to connect Evanston to Chicago.

As with the other three elevated railroad companies in Chicago, the goal was to create a strong transportation system which connected the outlying neighborhoods together, reducing the need for horse drawn wagons (and later automobiles).
The construction of these elevated viaducts has much been accredited to the rapid growth of Chicago near the turn of the 20th century.
The new elevated line left the Union Loop at the intersection of Wells Street and Lake Street in downtown Chicago. The Union Loop was a 35 square block loop around central Chicago.
The Northwestern Elevated continued north from the Union Loop, across the Chicago River on a bridge shared with Wells Street.
Immediately after the line turned and followed Franklin Street, before turning parallel to Orleans Street. The line then turned due west, parallel to North Avenue, and back north along Sheffield Avenue.

The line opened to Wilson Station, just a day after the deadline. The city and railroad began a standoff over this, but ultimately the railroad convinced the city to extend the deadline.

The line would inevitably completed to Evanston and Wilmette along the Chicago, Milwaukee St. Paul & Pacific tracks.

By 1907, the railroad began a branch from N. Clark and W. Roscoe Streets into Ravenswood, and ended at Lawrence Avenue and Kimball Avenue.

In 1913, the other three companies (The South Side "L", The Lake Street "L" and The Metropolitan "L") came together to form the Chicago Elevated Railways Collateral Trust, forming complete crosstown service of Chicago for the first time.

By 1924, all companies completely merged to form the Chicago Rapid Transit Company (CRA).
Following WWII, the City of Chicago and Illinois Government favored consolidating the bus, streetcar and elevated/subway operators into one company. The Chicago Transit Authority was born in 1947.

The system continued to expand through the 1950s and 1960s, with construction taking place primarily along new Interstate Highways, including The Eisenhower (I-290) and the Dan Ryan (I-90/I-94)
A new color scheme was adopted to rename the lines in 1993. The colors include: Red, Green, Blue, Pink, Brown, Purple, Yellow and Orange.

This line was renamed the Brown Line between the Union Loop (later renamed "Loop") and Clark and Roscoe. From that point to Wilmette, it was known as Red.

The Ravenswood branch would also become known as part of the Brown Line.
07/17/21


The Lake Street Bridge is one of the most iconic bridges in Chicago, however it does not make the same appearances in films as the Wells Street Bridge.
The bridge is one of the most unique structures in Chicago, and one of only two that is a double deck structure.
The lower deck of the structure carries Lake Street, while the upper deck carries CTA "L" Trains.
This fixed trunnion bascule bridge is one of the finest in Chicago, joining the ranks of many other bridges, such as the Wells Street Bridge.
Chicago constructed many road bridges of this design, due to wide navigational channels.
The bridge is a double leaf style trunnion bascule bridge, with each leaf containing 6 riveted panels.
The bottom chords are curved on either end to allow the bridge to raise and lower, meaning the clear span of the river is only 164 feet, as the sides are much too low for navigation.
The substructures are made of concrete, which include an ornate abutments and operators tower. These substructures have been partially reinforced with steel sheathing.
In addition, the railroad deck contains an 12 panel, riveted Warren Pony Truss approach on the east side, which crosses Upper Wacker Drive. This pony truss connects directly to an 1890s elevated viaduct, part of the CTA.
Being located in downtown Chicago, with a large system of waterways; the bridge will raise and lower many times per day. Because of how massive the structure is, it is really unique to see how the bridge moves. The trunnion feature forces the bridge to pivot as it is being raised.
The previous bridges at this location also have a lot of history. The first bridge in Chicago was a ferry, built here in 1829. The first wooden floating bridge was built in 1849, and was destroyed by ice and replaced in 1859, again being replaced in 1885 by an iron swing bridge.
The current bridge was replaced without interrupting traffic, similar to the Wells Street Bridge. The design was originally supposed to be a vertical lift, although the bascule design was later favored.

When the new bridge was built, the leafs were assembled in upright position. The inner panels of the leafs were not completed with deck to allow traffic to pass through. When these leafs were completed, the swing bridge was opened, and the center cut out.
Next, the spans would be lowered, and the deck completed. The remaining portions of swing bridge would be cut out, and the new bridge completed.
Overall, the bridge appears to be in good condition, and is well maintained.
The author has ranked the bridge as being highly significant, due to the unique nature of the bridge.
The photo below is the construction of the new bridge. These photos were used with permission from Historicbridges.org.
The photo above is an overview. Unfortunately, the weather did not turn out how I would have liked, and thus this bridge is on my priority list for next time.

South Branch Chicago River Railroad Bridges
Upstream Confluence of N. Branch and Main Branch Chicago River
Downstream Congress Parkway Subway



Detail Photos

Citations

Source Type

Source

Build Date Dedication plaque
Contractor Dedication plaque
Railroad Line History Source ICC Valuation Information, Compiled by Richard S. Steele



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