Editing Blue Line (CTA)

{{Short description|Rapid transit line in Chicago}}
{{Use American English|date=May 2025}}
{{more citations needed|date=November 2024}}
{{Infobox rail line
| color                           = {{rcr|CTA|Blue}}
| name                            = Blue Line
| image                           = File:I-290 and UIC-Halsted station.jpg
| image_width                     = frameless{{!}}upright=1.35
| caption                         = A Blue Line train of [[7000-series (CTA)|7000-series]] cars leaving [[UIC&ndash;Halsted station]] on the Congress branch
| type                            = [[Rapid transit]]
| system                          = [[Chicago "L"]]
| status                          = Operating
| locale                          = [[Chicago]], [[Oak Park, Illinois|Oak Park]], [[Forest Park, Illinois|Forest Park]], and [[Rosemont, Illinois|Rosemont]], [[Illinois]]
| start                           = [[O'Hare (CTA station)|O'Hare]]
| end                             = [[Forest Park (CTA station)|Forest Park]]
| stations                        = 33
| routes                          = O'Hare–Forest Park
| daily_ridership                 = 72,475 (avg. weekday 2023)
| open                            = Oldest segment: {{Start date and age|1895|05|06}}<br>Current operation: {{Start date and age|1958|06|22}}
| close                           = 
| owner                           = Chicago Transit Authority
| operator                        = [[Chicago Transit Authority]]
| character                       = Expressway median, subway and [[Elevated railway|elevated]]
| stock                           = Mixed [[2600-series (CTA)|2600-]] and [[3200-series (CTA)|3200-series]], [[5000-series (CTA)|5000-series]] only on rush hour, [[7000-series (CTA)|7000-series]]<br />8-car trains (typical, maximum)
| linelength                      = {{convert|26.93|mi|km|1|abbr=on}}
| tracklength                     = 
| depot                           = [[Desplaines Yard]], [[Rosemont Yard]]
| tracks                          = 
| gauge                           = {{track gauge|ussg|allk=on}}
| electrification                 = {{600 V DC|conductor=third rail}}
| minradius                       = 
| speed                           = 
| elevation                       = 
| map                             = {{switcher
|{{maplink-road|from=Blue Line (CTA).map}}
|Show interactive map
|{{Blue Line (CTA)}}
|Show route diagram map
}}
| map_state                       = 
}}

The '''Blue Line''' is a {{convert|26.93|mi|km |adj=mid|-long}} [[Chicago "L"]] line which runs from [[O'Hare International Airport]] at the far northwest end of the city, through downtown via the [[Milwaukee–Dearborn subway]] and across the [[West Side, Chicago|West Side]] to its southwest end in [[Forest Park, Illinois|Forest Park]], with a total of 33 stations (11 on the Forest Park branch, 9 in the Milwaukee–Dearborn subway and 13 on the O'Hare branch). At about 27 miles, it is the longest line on the Chicago "L" system and second busiest, and one of the longest local subway/elevated lines in the world. It has an average of 72,475 passengers boarding each weekday in 2023.<ref name="cta-report">{{cite web | title=Annual Ridership Report - Calednar Year 2023 | publisher= [[Chicago Transit Authority]]|url=https://www.transitchicago.com/assets/1/6/2023_Annual_Ridership_Report.pdf| date= January 23, 2024| accessdate=November 21, 2024}}</ref>

Chicago's Blue Line and [[Red Line (CTA)|Red Line]] offer 24-hour service, every day, year-round. This makes Chicago, New York City, and Copenhagen the only three cities in the world to offer local nonstop rail service throughout their city limits 24 hours a day, seven days a week. The Blue Line is one of two lines in Chicago with more than one station having the same name, with the [[Green Line (CTA)|Green Line]] being the other. (The Blue Line has two stations at Harlem Avenue: one in the Kennedy Expressway on the Northwest side and one on the Eisenhower Expressway in [[Forest Park, Illinois]]. It also has two stations on Western Avenue: one on the segment between downtown and O'Hare, and one immediately west of downtown.) The Blue Line also has two in-system transfers (both in the Loop), and does not share tracks with any other 'L' line.

Before the adoption of color-coded names, the Blue Line was referred to as the '''West-Northwest''' Route, or more commonly, the '''O'Hare-Congress-Douglas''' route for its three branches. The Congress and Douglas branches were renamed for their terminals, '''Forest Park''' and '''54th/Cermak''', when the current color naming system was adopted in 1993. Blue Line service on the Douglas segment was replaced in April 2008 by the [[Pink Line (CTA)|Pink Line]].<ref name="CTAnews">{{cite web|url=http://www.transitchicago.com/blueline/|title=Blue Line|publisher=[[Chicago Transit Authority]]|location=[[Chicago]]}}</ref>

The Blue Line is one of five "L" lines that run into Chicago suburbs, with the others being the Green, [[Purple Line (CTA)|Purple]], Pink, and [[Yellow Line (CTA)|Yellow]] lines. The Blue Line runs in three suburbs: Rosemont, Oak Park, and Forest Park.

== Route ==
{{unreferenced section|date=November 2024}}
{{See also|Logan Square branch}}
{{multiple image
 |align = left
 |direction = vertical
 |width = 210
 |image1 = O'Hare station 2018.jpg
 |alt1 =
 |caption1 = The Blue Line terminal at [[O'Hare International Airport]]
 |image2 = Clark-Lake subway 2.jpg
 |alt2 =
 |caption2 = Clark/Lake station on the Milwaukee–Dearborn subway
 |image3 = Eisenhower Expressway.jpg
 |alt3 =
 |caption3 = The Blue Line tracks in the median of the [[Eisenhower Expressway]]
}}

=== O'Hare branch ===
The '''O'Hare branch''' is the longest section of the Blue Line ({{convert|14.6|mi|km}}) and comprises both the oldest and newest segments of the entire route. The line starts at [[O'Hare International Airport]] in [[O'Hare station|an underground station]] below the airport's main parking garage, with direct pedestrian access to Terminals 1, 2 and 3. The line emerges in the median of the O'Hare main access road ([[Interstate 190 (Illinois)|Interstate 190]]) just northwest of Terminal 5, about a mile (1.6&nbsp;km) west of Mannheim Road.

The line runs in the median of [[Interstate 190 (Illinois)|Interstate 190]] east through [[Rosemont, Illinois|Rosemont]]. The line has a station at River Road in {{cta|Rosemont}}, which is also the location of the northern storage yard and served as a temporary terminal from 1983 to 1984 while the O'Hare station was being completed. The tracks then tunnel beneath the [[Kennedy Expressway]]/[[Northwest Tollway]] interchange near the [[Des Plaines River]].

The line runs in the median of the Kennedy Expressway ([[Interstate 90 in Illinois|Interstate 90]]) until a point southeast of Addison Street, making stops at {{cta|Cumberland}}, {{cta|Harlem|Blue|O'Hare}}, {{cta|Jefferson Park}}, {{cta|Montrose|Blue}}, {{cta|Irving Park|Blue}} and {{cta|Addison|Blue}}. Between Montrose and Irving Park, the line tunnels beneath an express lane exit. South of Addison Street, the line descends into a subway and turns south under Kimball Avenue. The line travels under Kimball Avenue and [[Milwaukee Avenue (Chicago)|Milwaukee Avenues]] through [[Logan Square, Chicago|Logan Square]], making stops at {{cta|Belmont|Blue}} and {{cta|Logan Square|Blue}}.

South of Logan Square, the line emerges above ground onto an elevated structure parallel to Milwaukee Avenue. This section of structure, built in 1895 as part of the Metropolitan Elevated's [[Logan Square branch]], is the oldest portion of the Blue Line, and the sole section of the line on an elevated viaduct. The three stations on this section ({{cta|California|Blue}}, {{cta|Western|Blue|O'Hare}}, and {{cta|Damen|Blue}}) are also the only three stations on the line to use side platforms instead of island platforms.

=== Milwaukee–Dearborn subway ===
{{Main|Milwaukee–Dearborn subway}}
At the intersection of Ashland and Milwaukee Avenues, the Blue Line descends underground, swings over to Milwaukee Avenue, and continues southeast towards downtown under Milwaukee Avenue (with stops at {{cta|Division|Blue}}, {{cta|Chicago|Blue}} and {{cta|Grand|Blue}}). The line then turns east under Lake Street, crossing beneath the [[Chicago River]], and makes a stop at {{cta|Clark/Lake}}, where in-system transfers are provided to 'L' trains on the Loop.

East of Clark/Lake, the tracks swing south under Dearborn Street, with a continuous platform similar to the continuous platform used in the adjacent [[State Street subway]], with stops at {{cta|Washington|Blue}}, {{cta|Monroe|Blue}}, and {{cta|Jackson|Blue}}.

South of Jackson, the line turns west under [[Ida B. Wells Drive]] (with stops at {{cta|LaSalle}} and {{cta|Clinton|Blue}}, which is two blocks south of [[Chicago Union Station|Union Station]]). The tracks then emerge from a portal near {{cta|UIC-Halsted}} in the median of the [[Interstate 290 (Illinois)|Eisenhower Expressway]] (Interstate 290) and continue west.

=== Forest Park branch ===
{{Congress branch (CTA)}}
After exiting the subway, the tracks continue west in the median of the Eisenhower Expressway as the '''Forest Park branch''', formerly called the '''Congress branch''', successor to the Garfield Park Branch.

Immediately west of {{cta|Racine|Blue}}, the Forest Park branch tracks diverge to permit a ramp up to the Douglas Branch elevated structure. This ramp was formerly used in revenue service from 1958 to 2008 when the Blue Line operated over the Douglas branch and the Forest Park branch.

With the replacement of Douglas branch Blue Line service with the Pink Line, the ramp is now [[non-revenue track]]age used for the transfer of 5000 series trains that the Blue Line borrows from the Pink Line for weekday rush hour service. The Forest Park branch remains in the median of the expressway through the west side of Chicago until it reaches a portal at Lotus Avenue.

At this point, the tracks pass beneath the eastbound expressway lanes before emerging on the south side of the expressway next to the [[CSX Transportation]] ([[Baltimore and Ohio Chicago Terminal Railroad]]) tracks. The route passes through [[Oak Park, Illinois|Oak Park]] and into [[Forest Park, Illinois|Forest Park]]. In the vicinity of Desplaines Avenue the tracks rise and make an S-curve north over the expressway before terminating at the {{cta|Forest Park}} station.

== Operating hours and headways ==
Like the [[Red Line (CTA)|Red Line]], the Blue Line runs 24 hours a day. Most trains run between O'Hare and Forest Park stations, but others terminate at a different station along the line. On weekdays, service runs very frequently (10–20&nbsp;tph (trains per hour)) during rush hour (with some trains running short-turn services between UIC-Halsted and Jefferson Park or Rosemont), and 6–8&nbsp;tph during the midday and nighttime.<ref name=":0">{{cite web|title=Blue Line Trains schedule|url=https://www.transitchicago.com/assets/1/6/rail-tt_blue.pdf|work=Chicago Transit Authority|publisher=transitchicago.com|access-date=December 2, 2017}}</ref>

On Saturdays, service runs 8&nbsp;tph in the early morning, then increase to 10&nbsp;tph during the day, then 8&nbsp;tph at night. On Sundays, service runs 6–8&nbsp;tph early morning, then increase to 10&nbsp;tph all day, then 6&nbsp;tph at night. On the weekends, every other Blue Line train operates between O'Hare and UIC-Halsted only during the daytime, doubling the headways up to 5&nbsp;tph. Between approximately midnight and 5:30&nbsp;a.m., [[Night service (public transport)|night owl service]] on the Blue Line ranges between 3–4&nbsp;tph.<ref name=":0" />

== Rolling stock ==
{{unreferenced section|date=November 2024}}
{{Main|Chicago "L" rolling stock}}

The Blue Line is operated with the [[2600-series (CTA)|2600-series]], [[3200-series (CTA)|3200-series]], and [[7000-series (CTA)|7000-series]] railcars. In 2018, some of the 2600-series cars from the Blue Line fleet were replaced with the recently rehabbed [[3200-series (CTA)|3200-series]] cars from the [[Brown Line (CTA)|Brown]] and [[Orange Line (CTA)|Orange Lines]], with some of the 2600-series cars being reassigned to the Orange Line to replace them. These cars entered service on the Blue Line on September 17, 2018. In addition to the mix of the 2600-series and 3200-series cars, two 5000-series trainsets assigned to the [[Pink Line (CTA)|Pink Line]] make trips on the Blue Line during weekday rush hours, although these cars remain officially assigned to the Pink Line and are operated by Pink Line operators.

== History ==
{{See also|Logan Square branch|Douglas branch|Garfield Park branch|Metropolitan main line}}
{{maplink |frame=yes |zoom=10 |frame-align=left |frame-coordinates={{coord|41.91|-87.76}} |frame-width=250 |frame-height=200
|type1=line |from1=Blue Line (CTA).map
|type2=line |from2=Metropolitan combined blue.map
|type3=line |from3=The Loop (CTA).map
|text=The Metropolitan's trackage (dark blue) connected with [[the Loop (CTA)|the Loop]] (black), compared with the modern-day Blue Line (light blue)
}}

The Blue Line is the successor to the [[Metropolitan West Side Elevated Railroad]], which built a series of 'L' lines servicing the West Side of Chicago beginning in 1895. The first section to be built by the Metropolitan extended west in the vicinity of Van Buren Street from an independent terminal at Canal and Jackson Streets to Marshfield Avenue, and then northward in the vicinity of Paulina Street to Damen and Milwaukee Avenues. Service on this section began on May 6, 1895.<ref>{{cite news|title=New "L" Road Opens|newspaper=Chicago Daily Tribune|date=May 7, 1895|page=12}}</ref> The structure was completed from Damen Avenue to Logan Square on May 25, 1895.<ref>{{cite web |title=Logan Square |url=http://www.chicago-l.org/stations/logan_sq.html |website=chicago-l.org |access-date=16 July 2019}}</ref>

The next stage in the development of the West Side 'L' came on June 19, 1895, when the [[Garfield Park branch (CTA)|Garfield Park Branch]] was added, extending west in the vicinity of Van Buren Street and Harrison Street from Marshfield Avenue to Cicero Avenue.<ref>{{cite news|title=First Train on Garfield Park Division|newspaper=Chicago Daily Tribune|date=June 18, 1895|page=2}}</ref> <!--June 17 was the first day of TESTING. "Wednesday" (June 19) was the day the line entered service.--> An extension of service over the tracks of the [[Aurora, Elgin and Chicago Railroad]] to [[Forest Park station|a new terminal at Desplaines Avenue]] was established on March 11, 1905. A subsequent extension to [[Westchester, Illinois|Westchester]] opened on October 1, 1926, over tracks that had originally been built by the CA&E with the intentions of building a bypass route.<ref name="Westchester">{{cite web |url=http://chicago-l.org/operations/lines/westchester.html |title=Westchester branch |access-date=2009-02-21 |publisher=Chicago-L.org}}</ref> (Low ridership would prompt the CTA to discontinue service on the [[Westchester branch (CTA)|Westchester extension]] on December 9, 1951.<ref name="Westchester" />)

Another branch line was added to the rapidly growing Metropolitan on July 29, 1895, when trains began operating over the [[Humboldt Park Branch]], splitting off from the Logan Square Branch at {{cta|Damen|Blue}} and running west alongside North Avenue to a terminal at Lawndale Avenue.<ref name="Humboldt">{{cite web |url=http://chicago-l.org/operations/lines/humboldt.html |archive-url=https://web.archive.org/web/20030228223318/http://chicago-l.org/operations/lines/humboldt.html |url-status=live |archive-date=2003-02-28 |title=Humboldt Park branch |access-date=2009-02-21 |publisher=Chicago-L.org }}</ref> This was followed by still another addition when the Douglas Park Branch was placed in operation as far south as 18th Street on April 28, 1896.<ref name="Douglas">{{cite web |url=http://chicago-l.org/operations/lines/douglas.html |title=Douglas branch |access-date=2009-02-21 |publisher=Chicago-L.org}}</ref>

As the southwest area of the city developed, the Douglas Park Branch was extended from 18th Street to Western Avenue in September 1896; to Pulaski Road in June 1902; to Cicero Avenue in December 1907; to Central Avenue in August 1912; to 62nd Avenue in August 1915, and to Oak Park Avenue in [[Berwyn, Illinois|Berwyn]] on March 16, 1924. The Douglas Park branch was later cut back to 54th Avenue in [[Cicero, Illinois|Cicero]].

The Metropolitan West Side Elevated began service onto the Loop on October 11, 1897,<ref>{{cite news|title=Polly "L" on the Loop|newspaper=Chicago Daily Tribune|date=October 11, 1897|page=11}}</ref> and a rush period [[Wells Street Terminal|stub terminal at Wells Street]] was added October 3, 1904. For much of the early 20th century and through the 1940s, service on the West Side Elevated lines went unchanged until 1947, when the [[Chicago Transit Authority]] took control of the 'L', initiating a series of massive service cuts and station closings (that would last until the 1980s).{{Citation needed|date=August 2008}}

The Metropolitan lines began to be reshaped into the current Blue Line on February 25, 1951, when the CTA opened the Milwaukee-Dearborn Subway, connecting the Logan Square Branch with the Loop on a fast, efficient and more direct routing to downtown, rather than the previous circuitous route that saw these trains entering the Loop at the southwest corner.<ref>{{cite news|last=Buck|first=Thomas|title=New Subway to Northwest Side Opened|newspaper=Chicago Daily Tribune|date=February 25, 1951|page=1}}</ref> With opening of the Dearborn Subway, the old elevated alignment between Evergreen Portal and Marshfield Junction was decommissioned, used only for moving out-of-service rail cars. The northern section of the connection between Evergreen Avenue and Lake Street was demolished in the 1960s, leaving the Lake Street to Douglas Branch section—better known as the Paulina Connector—the only section still in operation. The Humboldt Park Branch was cut back to a full-time shuttle between Damen and Lawndale, and discontinued a year later on May 3, 1952.

The Garfield Park elevated was replaced by the Congress line on June 22, 1958,<ref>{{cite news|title=12,000 Ride CTA Congress Line on First Day|newspaper=Chicago Daily Tribune|date=June 23, 1958|page=4}}</ref> pioneering the world's first use of rail rapid transit and a multi-lane automobile expressway in the same grade-separated right-of-way.<ref>{{cite news|title=Hail New Era of Transit in Congress Way|last=Thompson|first=John H.|newspaper=Chicago Daily Tribune|date=June 21, 1958|page=7}}</ref> ([[Pacific Electric|Pacific Electric Railway]] "Red Car" tracks ran in the median of the Cahuenga Parkway in [[Los Angeles]] from 1944 until its expansion into the [[Hollywood Freeway]] in 1952, but the Pacific Electric service was an [[interurban streetcar]] rather than true rapid transit.) The new line connected with the Milwaukee-Dearborn Subway at the [[Chicago River]] and extended westward to Des Plaines Avenue in Forest Park. Loomis Ramp, built at this same time, permitted Douglas trains to be rerouted through the subway as well combining the Logan Square, Garfield Park (now Congress) and Douglas routes into the second through service in Chicago, the Congress/Douglas-Milwaukee Line.<ref>{{cite news|last=Freeburg|first=Russel|title=It's Free! So 20,000 Ride on New CTA Line|newspaper=Chicago Daily Tribune|date=June 22, 1958|page=3}}</ref>

A five-mile (8&nbsp;km) extension of the route via a short subway connection and the [[Kennedy Expressway]] median from [[Logan Square, Chicago|Logan Square]] to [[Jefferson Park, Chicago|Jefferson]] [[Jefferson Park Transit Center|Park]] opened on February 1, 1970. It was also built by the City of Chicago using federal money. Just before Logan Square, trains diverted off of the old elevated structure and entered the subway under Milwaukee and Kedzie Avenues to a portal just south of Addison Street, then emerged in the median of the Kennedy Expressway to the temporary terminal at Jefferson Park. The increased ridership that resulted from the extension prompted the CTA to build the second phase of the project, and extend the line the rest of the way to O'Hare. In March 1980, construction began on the O'Hare Airport extension, with the first section between Jefferson Park and River Road opening on February 27, 1983,<ref>{{cite press release |author=<!--Not stated--> |title=CTA Celebrates 20 Years of Service to O Hare Airport |url=https://www.transitchicago.com/cta-celebrates-20-years-of-service-to-o-hare-airport/ |location=[[Chicago]] |publisher=[[Chicago Transit Authority]] |date=2004-09-03 |access-date=2023-12-04}}</ref> and the final section to O'Hare on September 3, 1984.<ref>{{cite news|last=Papajohn|first=George|title=O'Hare's 'L' Service Gets Inaugural Cheer|newspaper=Chicago Tribune|date=September 4, 1984|page=A1}}</ref>

[[File:Cta3200 1987 luggage rack 386-87 -10 CTA.jpg|alt=luggage|thumb|A Blue Line train with luggage racks in the 1980s]]
On February 21, 1993, the CTA adopted a color-coded naming system to the rapid transit system, and the West-Northwest route (O'Hare-Congress/Douglas) became the Blue Line.

On October 15, 2015, the CTA announced the completed installation of [[4G]] wireless service on the Blue Line in between the [[Logan Square (CTA station)|Logan Square]] and [[Belmont (CTA Blue Line station)|Belmont]] stations. In the future this will mean that the CTA will be the largest rapid transit system with 4G coverage in subway tunnels and stations, this is targeted for the end of 2015.<ref>{{Cite web |title=Mayor Emanuel Announces First Chicago Transit Authority Subway Section Now Offers Chicagoans 4G Wireless Service |url=http://www.transitchicago.com/news/default.aspx?Month=&Year=&Category=2&ArticleId=3470 |archive-url=https://web.archive.org/web/20151019145555/http://www.transitchicago.com/news/default.aspx?Month=&Year=&Category=2&ArticleId=3470 |archive-date=2015-10-19 |access-date=2015-10-18 |website=Transit Chicago |url-status=live }}</ref>

=== Douglas branch ===
{{Main|Douglas branch|Pink Line (CTA)}}

The [[Douglas branch]] was once operated as part of the Blue Line. On April 28, 2008, the CTA eliminated Blue Line service on the Douglas branch, having been replaced by the [[Pink Line (CTA)|Pink Line]].<ref name="hilkevitch">{{cite news |title=Trial closing of Blue Line's Douglas branch starts |author=Jon Hilkevitch |newspaper=[[Chicago Tribune]] |date=April 28, 2008 }}</ref> The Loomis ramp that connects the Congress branch to the Douglas branch remains intact for non-revenue equipment moves as the only track connection between the Blue Line and the rest of the system.

On April 26, 1998, the Douglas Branch lost its overnight (owl) and weekend service and began operating between 4&nbsp;a.m. and 1&nbsp;a.m. on weekdays only as a result of budget cuts that also eliminated owl service on several other lines. Congress (Forest Park) service was effectively doubled through much of the day since service frequency from O'Hare required shorter headways than what would have been left.

While the CTA claimed Douglas branch reductions were due to low ridership, community activists also pointed to badly deteriorated infrastructure and funding shortfalls, as well as a perception that the CTA was uninterested in serving the West Side. On September 10, 2001, the CTA began a historic reconstruction of the Douglas Branch to repair its aging stations and tracks.<ref>{{Cite web|url=https://www.transitchicago.com/renew-the-blue-cta-breaks-ground-on-the-blue-line-renovation/?Month=9&Year=2001|title = Renew the Blue: Cta Breaks Ground on the Blue Line Renovation}}</ref> The work was officially completed on January 8, 2005, with new elevated structures, tracks, rebuilt stations, new communication networks and an upgraded power system along the route.<ref>{{Cite web|url=https://www.transitchicago.com/mayor-daley--cta-celebrate-completion-of-54th-cermak-branch-of-blue-line/?CategoryId=2&Year=2005&Month=18pg=2|title = Mayor Daley / Cta Celebrate Completion of 54Th /Cermak Branch of Blue Line}}</ref> On January 1, 2005, weekend service was restored.

[[File:54 Cermak CTA.JPG|thumb|Douglas branch stations like the [[54th/Cermak station]] were once served by the Blue Line.]]
In January 2005, the CTA held hearings on a proposal to reroute Douglas Branch service via the recently rebuilt Paulina Connector to the Lake Street [[Green Line (Chicago Transit Authority)|Green Line]], carrying Douglas trains to and around the elevated Loop for the first time since 1958. It was the first stage of what became the [[Pink Line (CTA)|Pink Line]]. This would have allowed a doubling of Blue Line trains to Forest Park on the Congress Branch, since service would no longer be divided between the Forest Park and 54th/Cermak terminals. Due to community fears that the Pink Line would not be enough, however, the CTA decided to retain limited Douglas Branch Blue Line service during weekday rush hours.

On February 15, 2006, the CTA approved the separate operation of the Douglas Branch plan.<ref>{{Cite press release|url=https://www.transitchicago.com/cta-board-approves-west-side-corridor-service-recommendations/?Month=2&Year=2006|title=CTA Board Approves West Side Corridor Service Recommendations|location=[[Chicago]]|publisher=[[Chicago Transit Authority]]}}</ref> All non-rush hour trains would all be routed via the Loop, [[Green Line (Chicago Transit Authority)|Green Line]] and Paulina Connector. During rush hour, service was available on the new route as well as the existing route via the Milwaukee-Dearborn Subway. These changes were scheduled to be implemented for a 180-day trial period beginning June 25, 2006, and after their evaluation in early 2007, the Pink Line remained in service.

Beginning April 28, 2008, the CTA began a six-month experimental ceasing of Blue Line operations on the Douglas.<ref name="hilkevitch" /> Despite maintaining that the service cut was an experiment, the CTA immediately covered Blue Line stations' directional signage for trains to {{cta|54th/Cermak}} with paint rather than temporary covering, suggesting it was a permanent discontinuation instead of a temporary one. All Douglas Branch operations are now served by the Pink Line.<ref>{{cite news| url=http://www.suntimes.com/news/transportation/838770,cta031208.article | title=Blue line's Douglas branch to get cut :: CHICAGO SUN-TIMES :: Transportation }} {{dead link|date=August 2010|bot=RjwilmsiBot}}</ref> On December 4, 2008, CTA announced its decision to permanently discontinue Blue Line service on the Douglas branch and to make the Pink Line permanent.<ref>{{Cite web|url=http://www.transitchicago.com/chicago-transit-board-approves-permanent-addition-of-west-sidewest-suburban-service-enhancements/?CategoryId=2&Year=2008&Month=12&pg=3|title = Chicago Transit Board Approves Permanent Addition of West Side/West Suburban Service Enhancements}}</ref>

== Accidents and incidents ==
* On July 11, 2006, a derailment caused a smoky fire in the Blue Line's Milwaukee-Dearborn Subway. There were injuries from [[smoke inhalation]], but no fatalities. The comparatively minor incident prompted heavy news coverage and a temporary stoppage of Chicago subway service because it occurred hours after [[2006 Mumbai train bombings|train bombings in Mumbai]] earlier the same day.<ref>{{Cite web |last=National Transportation Safety Board |date=September 11, 2007 |title=Railroad Accident Report: Derailment of Chicago Transit Authority Train Number 220 Between Clark/Lake and Grand/Milwaukee Stations, Chicago, Illinois, July 11, 2006 |url=https://www.ntsb.gov/investigations/AccidentReports/Reports/RAR0702.pdf}}</ref>
* On September 30, 2013, two Blue Line trains collided at {{cta|Harlem|Blue|Congress}} (Congress branch), injuring 33 people, after an outbound train was hit by an out-of-service train going the opposite direction on the same track. Earlier, the train had arrived at Forest Park, and went out of service. However, after the train pulled into the Desplaines Yard, it was left on. There were no passengers on the out-of-service train; the number of workers on it at the time of the crash was also an unknown. Also unknown was the total number of passengers on the outbound, in-service train. The investigation started shortly thereafter. Though service soon went back to normal, trains did not stop at the Harlem station until the late evening on Tuesday, October 1, 2013, to avoid interference with the scene and congestion.<ref>{{cite news| url=http://www.chicagotribune.com/news/local/breaking/chi-two-cta-trains-crash-on-blue-line-in-forest-park-20130930,0,1375440.story | work=Chicago Tribune | first=Jon | last=Hilkevitch | title=CTA: Video shows no one at controls of train before collision – chicagotribune.com}}</ref><ref>{{Cite web|url=https://www.huffingtonpost.com/2013/09/30/cta-blue-line-trains-coll_n_4016371.html|title = 2 CTA Blue Line Trains Collide, Dozens Sent to Hospital|website = [[HuffPost]]|date = 30 September 2013}}</ref> The [[National Transportation Safety Board|NTSB]] concluded that the probable cause was water in the control cables and insufficient securing of unattended equipment.<ref>{{cite web |title=Railroad Accident Brief: Collision of Two Chicago Transit Authority Trains |url=https://www.ntsb.gov/investigations/AccidentReports/Pages/RAB1502.aspx |publisher=National Transportation Safety Board |access-date=18 March 2020}}</ref>
* In the early morning hours of March 24, 2014, a Blue Line train [[O'Hare station train crash|derailed at O'Hare]] at the end of its run. Initial reports said that 32 passengers on the train were injured, but none of the injuries were considered life-threatening.<ref>{{Cite news|url=http://galleries.apps.chicagotribune.com/chi-blue-line-train-crash-ohare-photos-20140324/|title = Blue Line train crashes at O'Hare|newspaper=[[Chicago Tribune]]|location=[[Chicago]]}}</ref> The station reopened on Sunday, March 30, 2014, at 2:00&nbsp;p.m.<ref>{{cite news| url = https://abc7chicago.com/archive/9485216/| title = CTA Blue Line O'Hare stop reopens Sunday following derailment {{!}} ABC7 Chicago {{!}} abc7chicago.com – ABC7 Chicago}}</ref>
* On April 10, 2019, a Blue Line train derailed in the tunnel near [[O'Hare station]].<ref>{{Cite news|url=https://abc7chicago.com/cta-blue-line-service-resumes-after-train-derails-between-ohare-rosemont;-1-injured/5242543/|last=Cauguiran|first=Cate|work=[[ABC News (United States)|ABC News]]|publisher=[[ABC Owned Television Stations]]|location=[[Chicago]]|title = CTA Blue Line service resumes after train derails between O'Hare, Rosemont; 1 injured|date = 11 April 2019}}</ref><ref>{{Cite news|url=https://chicago.cbslocal.com/2019/04/11/cbs-2-exclusive-human-error-to-blame-for-cta-blue-line-derailment-cta-workers-union-says/|title=Human Error to Blame for CTA Blue Line Derailment, CTA Workers Union Says|last=Hickey|first=Megan|work=[[CBS News]]|location=[[Chicago]]|publisher=[[CBS News and Stations]]|date=11 April 2019}}</ref>
* On September 2, 2024, four people were killed in a [[2024 Chicago train shooting|mass shooting]] on a Blue Line train as it traveled between the [[Oak Park station (CTA Blue Line)|Oak Park]] and [[Harlem station (CTA Blue Line Forest Park branch)|Harlem]] stations. The gunman was arrested after boarding the [[Pink Line (CTA)|Pink Line]].<ref name="hilkevitch"/><ref>{{Cite news |last=Kaufman |first=Elyssa |last2=Feurer |first2=Todd |last3=Rezaei |first3=Asal |date=September 2, 2024 |title=4 people shot and killed on Chicago-area Blue Line train, suspect in custody |url=https://www.cbsnews.com/chicago/news/shots-fired-at-chicago-areas-forest-park-blue-line/ |access-date=September 3, 2024 |work=[[CBS News]]}}</ref>

== Expansion ==

=== Line extensions ===
For years, there has been discussions of extending the [[O'Hare, Chicago|O'Hare]] terminus of the Blue Line westward to [[Schaumburg, Illinois|Schaumburg]], but that has been changed, due to recent developments involving the planning of the [[Suburban Transit Access Route (Metra)|Metra STAR Line]] and various other transportation projects<ref>{{cite news |last1=Nitkin |first1=Alex |title=The CTA Has Interesting Ideas For a Blue Line Extension Sitting on the Shelf |url=https://www.chicagomag.com/city-life/march-2018/the-cta-has-interesting-ideas-for-a-blue-line-extension-sitting-on-the-shelf/ |access-date=1 April 2025 |publisher=Chicago Magazine |date=March 23, 2018}}</ref>.

However, in 2008, the [[Regional Transportation Authority (Illinois)|Regional Transit Authority]] revealed a plan to the RTA board to expand commuter rail and bus service, which included a {{convert|13.3|mi|km|adj=on}} extension of the Blue Line, from its current western terminus at Forest Park to [[Yorktown Center]] in [[Lombard, Illinois]]. Several feeder bus services would also be implemented in this plan. The prospect of this extension was also listed in the Chicago region's 2030 master plan.<ref>{{cite news | url=http://www.chicagotribune.com/news/local/chi-corridor_22feb22,0,3797698.story | title=Cook-DuPage corridor project would extend Blue Line |newspaper=Chicago Tribune| access-date=2008-03-04 | archive-url=https://web.archive.org/web/20080226021531/http://www.chicagotribune.com/news/local/chi-corridor_22feb22,0,3797698.story | archive-date=2008-02-26 | url-status=dead }}</ref>

In 2013, the idea of an infill station at Nagle and Bryn Mawr Avenues was postponed. Such a station remains only idea but may come to fruition in the future because that particular stretch of the line, between Jefferson Park and Harlem, is the second longest on the 'L' system without a station, behind the gap on the [[Yellow Line (CTA)|Yellow Line]] between {{cta|Oakton-Skokie}} and {{cta|Howard}}, although the Yellow Line was designed this way to quickly shuttle passengers to/from the Howard station (the Howard station serves the Red and Purple Lines).<ref>[http://www.dnainfo.com/chicago/20130205/norwood-park/cta-blue-line-stop-at-nagle-avenue-would-have-big-impact-on-community Coalition Pushes for CTA Blue Line Stop at Nagle, Bryn Mawr Avenues – Norwood Park – DNAinfo.com Chicago<!-- Bot generated title -->] {{webarchive|url=https://web.archive.org/web/20130209121122/http://www.dnainfo.com/chicago/20130205/norwood-park/cta-blue-line-stop-at-nagle-avenue-would-have-big-impact-on-community |date=2013-02-09 }}</ref>

In December 2016, Pace introduced the on-highway BRT [[Pace I-90 Express|I-90 Express]] service. The successor to the Blue Line Extension and the STAR Line, this service serves as an extension of the Blue Line and provides rapid service along I-90 all the way to Elgin.

=== Extra tracks ===
{{Main|Chicago Aurora and Elgin Railroad}}

The surface right-of-way for the Congress Branch, including overcrossings, undergrade bridges and two short tunnels under the expressway, contains space for one extra track between Forest Park and Kenton Avenue and two extra tracks from Kenton to the tunnel portals at UIC-Halsted. It was intended that the interurban Chicago Aurora and Elgin Railroad, which had utilized the Garfield Park Elevated until 1953 to reach its Loop terminal at Wells Street, would use these extra tracks. However, the CA&E ceased passenger service on July 3, 1957, before track construction had started.<ref name=krambles>{{cite book|last=Krambles|first=George and Art Peterson|title=CTA at 45|year=1993|publisher=George Krambles Transit Scholarship Fund|location=Oak Park, Illinois, USA|isbn=0-9637965-4-2|pages=118–119}}</ref> The CTA also considered plans of its own to add these as express tracks (and service) over the years, as well as a rerouting of the [[Green Line (CTA)|Lake Elevated]] onto the Paulina Elevated (today's [[Pink Line (Chicago Transit Authority)|Pink Line]]) into a new quadrant of the junction with the Douglas Line at Racine, but these plans were discarded for alternative plans and today the system has an entirely separate line in the system, the Pink Line.<ref name=":1">{{cite web|last=Garfield|first=Graham|title=FAQ: Tracks and Connectiona|url=http://www.chicago-l.org/FAQ.html#3.9|work=Chicago-L.org|access-date=16 May 2011}}</ref>

=== Stub tunnels ===
{{Further|Chicago Central Area Transit Plan}}

[[File:Distributor Subway.jpg|thumb|250x250px|An artist's rendition of the proposed Monroe Street Subway, at Dearborn Street, with various underground levels]]
The dual portals of the Congress Branch at UIC-Halsted are actually quadruple. Two extra portals exist to the north of the Blue Line portals, which extend only a few dozen feet beyond the portals. These were intended to accommodate future expansion, including a new CA&E line to a new terminal.<ref name=":1" /> Among those plans were a loop subway system via Congress, Dearborn, Lake, and Clinton when the Milwaukee-Dearborn-Congress Subway was completed between 1951 and 1958, and a shuttle subway route under Jackson Street to Grant Park (1958, "New Horizons for Chicago Metropolitan Area", ''CTA'').

Between 1968 and 1978, a plan in the form of [[Chicago Central Area Transit Plan|another subway corridor]] in the Downtown area was proposed, which was to be routed from UIC-Halsted Station through the north portals, then north under Des Plaines Street to Monroe Street and east under Monroe Street to [[Grant Park (Chicago)|Grant Park]] and [[Millennium Park]], where it was to split into two branches: one north to Walton Street serving the North Michigan Avenue area and the other southeast to McCormick Place utilizing [[Metra Electric]] right-of-way. Though these portals are still not used, the subway corridor plan under Monroe Street was never officially canceled when the Crosstown and [[Chicago Central Area Transit Plan|Loop Subway]] projects were deferred in 1979. It remains to this day an active program.

Between Grand/Milwaukee and Clark/Lake in the Milwaukee-Dearborn Subway, two more stub tunnels exist, continuing west under Lake Street while the in-service tracks turn northwest under Milwaukee Avenue. This junction (actually a stacked junction), built in the 1940s along with the subway, was intended for a never-built connection to, or subway replacement of the Lake Street Elevated.<ref name=chgo-l>{{cite web|last=Garfield|first=Graham|title=FAQ: Abandoned, Disused & Demolished Facilities/Lines|url=http://www.chicago-l.org/FAQ.html#6.2|work=Chicago-L.org|access-date=16 May 2011}}</ref> In the late 1960s through the mid-1970s, they were also proposed to be a service link between the Dearborn Subway and a high-speed subway route in Randolph Street to replace a portion of the Lake Street 'L' east of Damen Avenue (''Transit Planning Study Chicago Central Area'', April 1968).

== Station listing ==
{| class="wikitable plainrowheaders" align=center
|-
!Municipality
!Neighborhood
!Station
!Connections
|-
|[[Chicago]]
|[[O'Hare, Chicago|O'Hare]]
|{{cta|O'Hare}} {{access icon}}
|{{rint|air|link=O'Hare International Airport}} [[O'Hare International Airport]]<br />{{rint|chicago|ats}} [[Airport Transit System]]
|-
|colspan=2|[[Rosemont, Illinois|Rosemont]]
| {{cta|Rosemont}} {{access icon}} [[File:Aiga parking inv.svg|20px]]
|
|-
|rowspan=30|[[Chicago]]
|[[O'Hare, Chicago|O'Hare]]
| {{cta|Cumberland}} {{access icon}} [[File:Aiga parking inv.svg|20px]]
|
|-
|[[Norwood Park, Chicago|Norwood Park]]
| {{cta|Harlem|Blue|O'Hare}} {{access icon}} [[File:Aiga parking inv.svg|20px]]
|
|-
|[[Jefferson Park, Chicago|Jefferson Park]]
| {{cta|Jefferson Park}} {{access icon}} {{rint|rail|size=15|alt=Metra or South Shore connection}}
|{{rint|chicago|metra}} [[Metra]] trains: {{rcb|Metra|upnw|inline=square}}<br />{{rint|bus|brt}} [[Pace (transit)|Pace BRT]]: [[Pace Pulse]]
|-
|[[Irving Park, Chicago|Irving Park]]/<wbr/>[[Portage Park, Chicago|Portage Park]]
| {{cta|Montrose|Blue}} {{rint|rail|size=15|alt=Metra or South Shore connection}}
|{{rint|chicago|metra}} [[Metra]] trains: {{rcb|Metra|mdn|inline=square}} <small>(at {{stl|Metra|Mayfair}})</small>
|-
|[[Irving Park, Chicago|Irving Park]]
| {{cta|Irving Park|Blue}} {{rint|rail|size=15|alt=Metra or South Shore connection}}
|{{rint|chicago|metra}} [[Metra]] trains: {{rcb|Metra|upnw|inline=square}} <small>(at {{stl|Metra|Irving Park}})</small>
|-
|[[Irving Park, Chicago|Irving Park]]/<wbr />[[Avondale, Chicago|Avondale]]
| {{cta|Addison|Blue}} {{access icon}}
|
|-
|[[Avondale, Chicago|Avondale]]/<wbr />[[Logan Square, Chicago|Logan Square]]
| {{cta|Belmont|Blue}}
|
|-
| rowspan="3" |[[Logan Square, Chicago|Logan Square]]
| {{cta|Logan Square|Blue}} {{access icon}}
|
|-
| {{cta|California|Blue}}
|
|-
| {{cta|Western|Blue|O'Hare}} {{access icon}}
|
|-
| rowspan="4" |[[West Town, Chicago|West Town]]
| {{cta|Damen|Blue}}
|
|-
| {{cta|Division|Blue}}
|
|-
|{{cta|Chicago|Blue}}
|
|-
|{{cta|Grand|Blue}}
|
|-
| rowspan="5" |[[Chicago Loop|The Loop]]
| {{cta|Clark/Lake}} {{access icon}}
|{{rint|metro}} [[Chicago Transit Authority|CTA]] [[Chicago "L"|"L" trains]]: {{rcb|CTA|Brown|inline=route}} {{rcb|CTA|Green|inline=route}} {{rcb|CTA|Orange|inline=route}} {{rcb|CTA|Pink|inline=route}} {{rcb|CTA|Purple|inline=route}}
|-
| {{cta|Washington|Blue}}
|{{rint|metro}} [[Chicago Transit Authority|CTA]] [[Chicago "L"|"L" trains]]: {{rcb|CTA|Red|inline=route}} <small>(at {{cta|Lake|Red}})</small>
|-
| {{cta|Monroe|Blue}}
|
|-
| {{cta|Jackson|Blue}} {{access icon}}
|{{rint|metro}} [[Chicago Transit Authority|CTA]] [[Chicago "L"|"L" trains]]: {{rcb|CTA|Red|inline=route}} <small>(at {{cta|Jackson|Red}})</small>, {{rcb|CTA|Brown|inline=route}} {{rcb|CTA|Pink|inline=route}} {{rcb|CTA|Purple|inline=route}} {{rcb|CTA|Orange|inline=route}} <small>(at {{cta|Library}})</small>
|-
| {{cta|LaSalle}} {{rint|rail|size=15|alt=Metra or South Shore connection}}
|{{rint|chicago|metra}} [[Metra]] trains: {{rcb|Metra|ri|inline=square}} <small>(at {{stl|Metra|LaSalle Street}})</small>
|-
| rowspan="5" |[[Near West Side, Chicago|Near West Side]]
| {{cta|Clinton|Blue}} {{rint|rail|size=15|alt=Metra or South Shore connection}}
|{{rint|chicago|metra}} [[Metra]] trains: {{rcb|Metra|bnsf|inline=square}}, {{rcb|Metra|hc|inline=square}}, {{rcb|Metra|mdn|inline=square}}, {{rcb|Metra|mdw|inline=square}}, {{rcb|Metra|nc|inline=square}}, {{rcb|Metra|sw|inline=square}} <small>(at {{stl|Metra|Union Station}})</small><br />{{rint|us|amtrak}} [[Amtrak]] long-distance: ''[[California Zephyr]]'', {{lnl|Amtrak|Cardinal}}, {{lnl|Amtrak|City of New Orleans}}, ''[[Empire Builder]]'', {{lnl|Amtrak|Floridian}}, ''[[Lake Shore Limited]]'', ''[[Southwest Chief]]'', ''[[Texas Eagle]]'' <small>(at {{stl|Metra|Union Station}})</small><br />{{rint|us|amtrak}} [[Amtrak]] intercity: {{lnl|Amtrak|Blue Water}}, {{lnl|Amtrak|Borealis}}, ''[[Hiawatha (Amtrak train)|Hiawatha]]'', {{lnl|Amtrak|Illini and Saluki}}, {{lnl|Amtrak|Illinois Zephyr and Carl Sandburg}}, ''[[Lincoln Service]],'' {{lnl|Amtrak|Pere Marquette}}, {{lnl|Amtrak|Wolverine}} <small>(at {{stl|Metra|Union Station}})</small>
|-
| {{cta|UIC–Halsted}} {{access icon}}
|
|-
| {{cta|Racine|Blue}}
|
|-
| {{cta|Illinois Medical District}} {{access icon}}
|
|-
|{{cta|Western|Blue|Congress}}
|
|-
| rowspan="2" |[[East Garfield Park, Chicago|East Garfield Park]]
| scope="row" style="background-color: #bbb" | {{cta|California|Congress}}
| scope="row" style="background-color: #bbb" | Closed September 2, 1973
|-
| {{cta|Kedzie–Homan}} {{access icon}}
|
|-
| rowspan="2" |[[West Garfield Park, Chicago|West Garfield Park]]
| {{cta|Pulaski|Blue}}
|
|- style="background-color: #bbb"
|{{cta|Kostner|Congress}}
|Closed September 2, 1973
|-
| rowspan="2" |[[Austin, Chicago|Austin]]
| {{cta|Cicero|Blue}}
|
|- style="background-color: #bbb"
|{{cta|Central|Congress}}
|Closed September 2, 1973
|-
| rowspan="2" colspan=2 |[[Oak Park, Illinois|Oak Park]]
| {{cta|Austin|Blue}}
|
|-
| {{cta|Oak Park|Blue}}
|
|-
| rowspan="2" colspan=2 |[[Forest Park, Illinois|Forest Park]]
| {{cta|Harlem|Blue|Congress}}
|
|-
| {{cta|Forest Park}} {{access icon}} [[File:Aiga parking inv.svg|20px]]
|
|}

== References ==
{{Reflist|30em}}

== External links ==
{{Attached KML |display=title,inline}}
{{commons category|CTA Blue Line}}
* [https://www.transitchicago.com/blueline/ Blue Line] at [https://www.transitchicago.com/ CTA official site]
{{O&#39;Hare International Airport|state=expanded}}
{{Chicago L}}

{{authority control}}

[[Category:Airport rail links in the United States|Chicago O'Hare]]
[[Category:Chicago "L" lines| ]]
[[Category:Railway lines in Chicago]]
[[Category:Railway lines in highway medians]]
[[Category:1895 establishments in Illinois]]
[[Category:Railway lines opened in 1895]]
[[Category:O'Hare International Airport]]