Blue Line: O'Hare branch


Current Line w/Station


Accessible Station

Current Line in subway


Park'n'Ride lot

Demolished Line w/Former Station


Airport connection

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Service Notes:

  Hours of Operation: Service at all times
  Length of Route: 14.38 miles
    Milwaukee Elevated: 2.2 miles
    Milwaukee-Kimball Subway: 1.2 miles
    Kennedy-O'Hare Extension: 10.98 miles

Number of Stations: 13 stations

  Car Types Assigned: 2600-series, 3200-series, 5000-series*, 7000-series (see Car Assignment sheet for latest car assignments)
    * 5000-series cars assigned to 54th Yard, run lite to Blue Line for rush period trips


Brief Description:

The O'Hare branch of the Blue Line is made of three sections of three different vintages: the Milwaukee Elevated, Milwaukee-Kimball Subway and Kennedy Extension, and O'Hare Extension.


Milwaukee Elevated

What is now the Milwaukee Elevated -- the portion of the O'Hare branch of the Blue Line between Evergreen Portal south of Damen station and the Logan Square Portal north of California station -- actually represents a remnant of the Metropolitan Elevated's Northwest branch. The Metropolitan West Side Elevated Railroad Company -- more commonly referred to as 'the Met' -- built the Milwaukee Elevated in 1895 as part of its vast network of lines on the West and Northwest Sides. Northwest Side trains originally took a more circuitous route to and from downtown, predating the construction of the Milwaukee-Dearborn Subway. Heading outbound from the Loop, trains traversed the Met's four-track main line paralleling Van Buren Street to Marshfield Junction, where the four-track line split into three two-track branches. The Northwest branch headed due north parallel to Paulina Avenue to Milwaukee Avenue near around Evergreen Street, then turned northwest paralleling Milwaukee Avenue. The Northwest service continued northwest along Milwaukee to a terminal at Logan Square, near Kedzie and Logan Boulevard. Just beyond Robey (Damen) station, the branch split again, with Humboldt park service turning west along North Avenue to Lawndale. The portion of the Northwest branch along Milwaukee between Evergreen and Logan Square -- just over half of the original route's length -- is now what remains as the Milwaukee Elevated.


Kennedy Extension

The first postwar expansion of the "L" system (that was not a line started before the war, a replacement for an existing line, or the resumption of a previous service) came in the form of two lines built in the medians of expressways, a form first pioneered in Chicago on the Congress Line. The Kennedy project was an extension of the Milwaukee Line on the Northwest Side. This project, along the entirely new Dan Ryan Line on the city's South Side and a short 0.25 mile extension of the Englewood branch from Loomis to Ashland/63rd, were funded in part by a $195 million general public works bond issue passed by the general assembly in 1966. The cost of the Kennedy and Dan Ryan projects amounted to $113 million before their completion.

The Kennedy Line, constructed between 1967 and 1970, was the second of the two projects -- the Kennedy and Dan Ryan -- to open. The two lines were under design and construction together, and although the Kennedy's end-to-end length is shorter than that of the Dan Ryan, it included more complicated and time-consuming subway construction. The Kennedy Line extends 5.2 miles northwest of the Milwaukee Elevated's former terminal at Logan Square. The extension actually branches off the Milwaukee Elevated at Sacramento Avenue, south of the Logan Square terminal (which was abandoned as a result) and enters a new subway underneath Milwaukee Avenue. The subway turns north under Kimball Avenue (3400W) and crosses under the eastbound lanes of the John F. Kennedy Expressway at School Street (3300N). Here, the line ascends to the surface and continues northwest another four miles in the median of the Kennedy Expressway to the terminal at Jefferson Park (5400N).


O'Hare Extension

The success (in terms of increased ridership, at least) of the Kennedy Extension of the old Milwaukee "L" line to Jefferson Park convinced the CTA that it was worth going through with their plan to continue the line to O'Hare International Airport on the far Northwest Side of the city. The extension was undertaken in the early 1980s and opened as far as River Road (now Rosemont station) on February 27, 1983 and to its final terminus at O'Hare on September 3, 1984.

The most noticeable change between the Kennedy Extension and the O'Hare Extension are in the design of the station facilities. Whereas all three median stations on the Kennedy project were designed by Skidmore Owings & Merrill, were of the same basic design, and were rather basic and spartan (though considered very "modern" at the time), the four O'Hare Extension stations -- Harlem, Cumberland, River Road, and O'Hare -- were designed by a different architectural firm with an eye toward originality and spaciousness. The four stations are also spaced farther apart -- about two miles -- and all were equipped with elevators and escalators. Adjacent to the River Road station a new yard and shop were built for the line to replace the facility north of Jefferson Park, which had to be demolished so the line could be extended. The 12-car Rosemont inspection shop and 260-car yard were built in a previously unused area between the ramps of the I-90/I-294/I-190 interchange. West of Rosemont Yard, the route continues in the median of the Kennedy Expressway (now Interstate 190 to O'Hare) to a short subway, which leads into the O'Hare terminal station, a three-track (the center track is for holding a reserve train) two-platform column-free facility built beneath a parking garage.

The O'Hare Line was the CTA first extension into completely new territory in more than half a century. Results were encouraging, as new office parks and retail outlets sprung up along the new rapid transit line in the Interstate 90 corridor. And those who thought only airport workers would ride the "L" to O'Hare were quickly proved wrong. Airline passengers took to the convenience, speed, and dependability of direct rapid transit service. So did workers in the corridor. In the next decade, the wisdom of this extension would be repeated at Chicago's other airport, Midway.


Your New Blue: O'Hare Branch Track, Station and Other Improvements

On December 5, 2013, Mayor Rahm Emanuel and Governor Pat Quinn announced a comprehensive improvement plan for the Blue Line O'Hare Branch (including the northern portion of the Dearborn Subway), an overhaul that would provide faster travel times and updated stations while creating more than 1,300 jobs.

The $492 million plan, called Your New Blue, includes several track and station improvement projects along a 12.5-mile stretch of the Blue Line between the Grand and Cumberland stations, as well as upgrades to the signal system between the Jefferson Park and O'Hare stations.

The project, beginning construction in 2014 and originally planned to last four years, was a package of several discrete projects ranging from station improvements to track renewal, signal replacement, traction power upgrades, and subway tunnel water mitigation efforts. Individual projects included:

The track renewal built upon the work done in the Dearborn Subway in 2007-08 and on the O'Hare Branch between Addison and O'Hare in 2008. With the track work planned under the Your New Blue project, all of the track between O'Hare and Downtown, though the Halsted Portal, will have been renewed.

These improvements were intended to provide faster, more comfortable and more reliable commutes for the more than 80,000 customers who each weekday used stations along the branch, which had 25 million rides in 2012. Ridership on the O'Hare Branch was growing rapidly, with more than 25 million station entries in 2012. Weekday ridership grew 25 percent over the previous five years since 2013, and 33 percent over the previous 10 years, outpacing the growth of the rail system as a whole. The stations receiving the most significant upgrades had experienced some of the biggest ridership jumps on the O'Hare branch.

Funding for Your New Blue was expected to come from local, state and federal sources. Approximately $136 million of the $492 million Blue Line rehabilitation project's price tag was paid for by the federal government, with $160 million coming from the state and $196 million from the city.

On February 5, 2015, Mayor Emanuel and U.S. Department of Transportation Secretary Anthony Foxx announced an additional $120 million of federal funding toward the Your New Blue program. Mayor Emanuel and Secretary Foxx were joined by CTA Chairman Terry Peterson, CTA President Forrest Claypool and area labor leaders at the Cumberland Blue Line station, one of 13 stations receiving improvements as part of Your New Blue. The efforts and advocacy for this project by Senator Dick Durbin were instrumental in getting the $120 million in funding through the Transportation Infrastructure Finance and Innovation Act (TIFIA). TIFIA provides credit assistance for qualified infrastructure projects, and is designed to fill market gaps and leverage other investment by providing capital. According to CTA, the TIFIA loan was cheaper than issuing bonds and was expected to save the CTA $41 million in financing during the life of the loan. A similar loan was used to pay for the $240 million renovation and expansion of the 95th Red Line station, which began in 2014. In addition to $120 million from the Transportation Infrastructure Finance and Innovation Act, the project will get a $16 million Transportation Investment Generating Economic Recovery grant, Foxx said.


Milwaukee Elevated Track Renewal

Efforts to secure funding for the track renewal work on the Milwaukee Elevated portion of the O'Hare branch began as early as late 2011, when an application was filed for funds from the Obama administration's TIGER III stimulus program, aimed at nationally significant projects with long-term benefits. The application included $39.6 million of the proposed $49.6-million federal grant to upgrade a 3.6-mile section of the Blue Line's O'Hare branch, between Damen and Belmont stations, and to rehab Damen and California stations. It also included a request for funding for what would become the City's Divvy bike-sharing program. 1

On August 14, 2013, the Chicago Transit Board approved the hire of a general contractor to perform track and structural work on the Blue Line O'Hare branch between the Damen and Logan Square stations. Following a competitive bid process, a contract valued at $20.4 million was awarded to Kiewit Infrastructure Co. for the Milwaukee Blue Line Track Renewal project.2

The track renewal project addressed slow zones not repaired during previous construction projects, and improved travel times, eliminated all slow zones and helped to slow the development of future slow zones, reducing future maintenance and repair costs. In addition to replacing deteriorated wooden rail ties along the elevated structure, project work also entailed the replacement of tie plates, fasteners and footwalks. Before the work, Blue Line trains operating on the Milwaukee Elevated incurred speed restrictions ranging from 35 mph to 15 mph -- rather than the full 55mph they would be able to travel on most portions if track conditions permitted it -- as a precautionary measure following track inspections that found that the wooden rail ties were in poor condition and in need of replacement.3

The Milwaukee Elevated track work required 10 temporary, weekend-only closures of small sections of the Blue Line, scheduled between March and August 2014. There were three types of "linecut" closures:

During these temporary closures, CTA provided free shuttle buses for Blue Line riders, as well as free transfers back into 'L' stations. The shuttles operated continuously, 24-hours per day during these partial closures. During the Western-Logan Square closures, shuttle buses operated between those two stations, making an intermediate stop at Milwaukee/California to service customers of the California station in between. Because Damen station is not ADA-accessible, during the Damen-Western and Damen-Logan Square closures the shuttle buses operated between Western or Logan Square, respectively, and Clark/Lake, making intermediate stops near each Blue Line station.

Funding for this project was a combination of sources, but is primarily funded with grants from the Illinois Department of Transportation and the TIGER III program (Transportation Investment Generating Economic Recovery), which was a federal grant program designed to improve transportation infrastructure.5


Damen, Western and California Station Renewal

The Chicago Transit Board approved the award of a $25.6 million design/build contract on February 5, 2014, for the rehabilitation of the Damen, Western and California stations as part of the Your New Blue program. F. H. Paschen, S.N. Nielsen and Associates, LLC was awarded the station rehabilitation contract following a competitive procurement process.

Work at Damen and California included renovation of the station houses, with restoration of the historic elements of the buildings, tuck-pointing, and replacement of windows and doors, rehabilitation of the platforms including the historic canopies and railing sections, and other improvements such as painting, sidewalk repairs, new lighting, signage and platform furniture, security cameras, PA systems and digital signs. In this project, neither California nor Damen got elevators to make them accessible for riders with disabilities. The CTA said its broader, long-range goal is to have all stations accessible with elevators, but the aim of the specific California and Damen station projects in the Your New Blue program was to extend the life of the stations. The scope of work at Damen and California required temporary closure of each station, with California closed September 4 to October 16, 2014, and Damen closed between October 20 and December 22, 2014.

At Western, which was renovated more recently (2000-01), work was more modest -- upgrade of the existing station house entrance plaza, installation of secure bike storage, upgrade of the existing station house entrance with the installation of new canopy over the sidewalk incorporating LED lighting to highlight the historic station facade, and replacement of existing metal roofing, handrails and guardrails on the north and south stairs. Work at Western did not require closure of the station.


Addison, Irving Park, Montrose, Harlem and Cumberland Station Renewal

On March 11, 2015, the Chicago Transit Board approved the award of a $25.6 million contract to F.H. Paschen and S.N. Nielsen for the renovation of five O'Hare branch stations as part of the Your New Blue modernization project. The contract is part of a $43 million station improvement program. The CTA began the rehabilitation of the Addison, Irving Park, Montrose, Harlem and Cumberland stations in fall 2015. The scope of these improvements included repairs to damaged concrete on the station platforms, replacement of existing deteriorated canopy skylights along the platforms, and modest renewal of the station house and platform areas including lighting, painting, and refurbishment of the platform furniture such as windbreaks, benches, and trash cans. Harlem and Cumberland received repairs to station house curtain walls, which had deteriorated in some areas. Addison received a new elevator to make the station ADA-accessible. Addison station was chosen to receive the accessibility improvements predominantly because of input from the accessibility community.6

Design work began in spring 2015, with construction work anticipated to begin at Addison by fall 2015. All station project work will be substantially completed by fall 2016.

All stations will remain open during the construction period, except for a small number of weekend-only closures at Addison and Montrose.


O'Hare Extension Signal Upgrade

The single largest project under the $492 million Your New Blue program is the $207 million track signal improvement project on the O'Hare Extension. The project, the first major signal upgrade since the Blue Line was extended by eight miles from Jefferson Park to O'Hare in the early 1980s, will help improve service, increase reliability and add more trains to the line during the busiest parts of the day.

The work will replace signal relay houses and the equipment inside them, cabling and switch machines between Jefferson Park and O'Hare. Specific benefits include:

Contractors work to trench for new signal cables at Foster Middle Track as part of signal upgrade construction, on May 4, 2019. For a larger view, click here. (Photo by Tony Coppoletta)

Some track replacement work will also occur in conjunction with the signal upgrade project in the O'Hare subway/tunnel approach.8

This will be the last section of the Blue Line to receive upgraded signals and interlocking systems, complementing a signal upgrade project completed on the rest of the Blue Line between Jefferson Park and Forest Park in 2005-2010. When completed, the upgraded signal systems will assure consistent, safe and reliable train operations on the entire Blue Line for many years to come. The new equipment will provide bi-directional traffic protection and be able to maintain headways at 90 seconds at 35mph. The Project will be designed with infrastructure provisions for a future Communication Based Train Control (CBTC) system, such as ducts for serial fiber/cables, ample spare room for hardware in each relay/ audio house and ideal locations for transponders, radio transmitters/antennae and wayside zone controllers.9

In addition to more common overnight and off-peak work requiring trains to share the same track in both directions, several temporary closures of portions of the Blue Line--typically between two stations and over a single weekend at a time--will need to occur to allow construction to be undertaken. There will be nine such weekend "linecuts", as well as two 9-day linecuts between O'Hare and Rosemont.

On April 18, 2018, the Chicago Transit Board awarded a $152.9 million contract to Kiewit-Aldridge AJV through a competitive bidding process for the Jefferson Park to O'Hare Signals Project. Notice to Proceed was given to the contractor on May 21, 2018.10

The first weekend linecut, between Jefferson Park and Harlem, occurred on May 3-6, 2019; additional linecuts covering the same zone took place on June 7-10, July 19-22, and August 9-12. A single linecut between Montrose and Jefferson Park occurred on July 26-29. For a nine-day period, between 10pm, Friday, September 27 and 4am, Monday, October 7, Blue Line service was suspended between Rosemont and O'Hare. To accommodate riders, CTA operated a robust free bus shuttle between the Rosemont and the O’Hare International Airport Bus/Shuttle Center, located above the O’Hare "L" station. The extended linecut was needed to allow crews to safely and more efficiently perform critical and complex track and signal work. There were also two linecuts between Harlem and Rosemont. A second O'Hare-Rosemont linecut will occur in 2020.

Construction is expected to be completed in 2021.11


Important Dates:



This Chicago-L.org article is a stub. It will be expanded in the future as resources allow.



1. Merrion, Paul. "Chicago seeks federal grant for Blue Line rehab, expanded bike-share program." Crain's Chicago Business, November 14, 2011.
2. "CTA Hires Contractor for Blue Line O'Hare Branch Track Project." CTA press release. August 14, 2013.
3. Ibid.
4. "Your New Blue: Service Changes & Alternatives." CTA website. Accessed April 12, 2014.
5. CTA (Aug 14, 2013), ibid.
6. Hilkevitch, Jon. "Blue Line renovations on 5 Northwest Side stations to start this fall." Chicago Tribune, March 11, 2015.7
7. "Your New Blue: Station, Track & Infrastructure Improvements." CTA website. Accessed May 13, 2019.
8. Ibid.
9. "Construction Project Briefing, April 10, 2019." Report to the CTA Board. April 10, 2019, accessed May 13, 2019.
10. "Your New Blue Modernization Program to Improve CTA Blue Line Service Moves Forward." CTA press release, April 18, 2018.
11. "Your New Blue: Station, Track & Infrastructure Improvements," ibid.