The Loop
A Brown Line train passes through Tower 12 as it makes the turn from Van Buren onto Wabash, while an Orange Line train waits for it to clear
Overview
Status	Operational
Locale	Chicago, Illinois, USA
Stations	8
Service
Type	Rapid transit
System	Chicago "L"
Services	Orange Green Purple Brown Pink
Operator(s)	Chicago Transit Authority
Daily ridership	40,341 (average weekday April 2024)[1]
History
Opened	1895–1897; 127 years ago (1897)
Technical
Track length	1.79 miles (2.9 km)
Number of tracks	2
Character	Elevated
Track gauge	4 ft 8+1⁄2 in (1,435 mm) standard gauge
Minimum radius	90 feet (27 m)
Electrification	Third rail, 600 V DC
Route map The Loop highlighted in black Show interactive map Legend Fifth/Lake (closed 1899) Clark/Lake State/Lake Randolph/Wells (closed 1995) Randolph/Wabash (closed 2017) Washington/​Wells Washington/​Wabash Madison/Wells (closed 1994) Madison/Wabash (closed 2015) Adams/Wabash Quincy LaSalle/Van Buren Library Dearborn/Van Buren (closed 1949) Show BSicon diagram map

The Loop (historically Union Loop) is the 1.79-mile-long (2.88 km) circuit of elevated rail that forms the hub of the Chicago "L" system in the United States. As of April 2024, the branch served 40,341 passengers on an average weekday.^[2] The Loop is so named because the elevated tracks loop around a rectangle formed by Lake Street (north side), Wabash Avenue (east), Van Buren Street (south), and Wells Street (west). The railway loop has given its name to Chicago's downtown, which is also known as the Loop.

Transit began to appear in Chicago in the latter half of the 19th century as the city grew rapidly, and rapid transit started to be built in the late 1880s. When the first rapid transit lines opened in the 1890s, they were independently owned and each had terminals that were located immediately outside of Chicago's downtown, where it was considered too expensive and politically inexpedient to build rapid transit. Charles Tyson Yerkes aggregated the competing rapid transit lines and built a loop connecting them, which was constructed and opened in piecemeal fashion between 1895 and 1897, finally completing its last connection in 1900. Upon its completion ridership on the Loop was incredibly high, such that the lines that had closed their terminals outside of downtown had to reopen them to accommodate the surplus rush-hour traffic.

In the latter half of the 20th century, ridership declined and the Loop was threatened with demolition in the 1970s. However, interest in historic preservation increased in the 1980s, and ridership has stabilized since.

Chicago Transit Authority signal tower 18 controls traffic of Purple and Brown Line trains entering from and exiting to the north, Pink and Green Line trains entering and exiting to the west, and Orange Line trains remaining in the Loop above the Wells and Lake street intersection.

A Brown Line train departing from Madison/Wabash; the station was eventually demolished and replaced with Washington/Wabash

Northward view from the Adams/Wabash station at night

Loop Elevated, with CNA Center and Old Colony Building

An Orange Line train approaches Quincy on the Wells Street portion of the Loop in 2008.

A street level view of Randolph/Wabash; like Madison/Wabash, this station was also demolished and replaced with Washington/Wabash.

The Loop includes eight stations: Clark/Lake and State/Lake are on the northern leg; Washington/Wabash and Adams/Wabash are on the eastern side; Harold Washington Library – State/Van Buren and LaSalle/Van Buren are on the southern leg; and Quincy and Washington/Wells are on the western side. In 2011, 20,896,612 passengers entered the 'L' via these stations.

Two towers control entry to and exit from the Loop. Tower 12 stands at the southeastern corner. Tower 18 stands watch over the three-quarter union located at the northwestern corner, which at one time was billed as the busiest railroad interlocking in the world.^[3] The current Tower 18 was placed into service on May 19, 2010, replacing the former tower on that site that was built in 1969.^[3]

Five of the eight 'L' lines use the Loop tracks:

• The Brown Line enters at Tower 18 on the northwest corner, served by the Purple Line during weekday rush hours. The Purple Line terminates by making a full circuit clockwise around the Inner Loop, while the Brown Line terminates by making a full circuit counterclockwise around the Outer Loop. Following the completion of a full circuit back to Tower 18, trains of these two lines return to their starting points.
• The Orange Line enters at Tower 12 on the southeast corner, and the Pink Line enters at Tower 18 on the northwest corner; both terminate by traveling clockwise around the Inner Loop before returning to their starting points.
• The Green Line is the only line to use Loop trackage but not terminate on it. Its trains run in both directions along the Lake and Wabash sides from Tower 18 to Tower 12, connecting the Lake Street branch and the South Side Elevated.

In the CTA system, the entire loop taken as a whole is considered the termination point of a line, just like a single station or stop is considered the termination point when outside the downtown loop.

Both of the 'L' lines with 24 hour service, the Blue Line and the Red Line, run in subways through the center of the Loop, and have both in-system and out-of-system transfers to Loop stations. The Yellow Line is the only 'L' line that does not run on or pass beneath the Loop.

When it was incorporated as a city in 1837, Chicago was dense and walkable, so there was no need for a transit system. Things began to change as Chicago grew rapidly in the 19th century.

Prior to construction of the Union Loop, Chicago's three elevated railway lines—the South Side Elevated Railroad, the Lake Street Elevated Railroad, and the Metropolitan West Side Elevated Railroad—each had their own terminal on the edges of downtown Chicago.^[4]

The Union Elevated Railroad Company was incorporated November 1894 for the purpose of constructing a loop in the heart of the city's business district.^[5] With tense opposition from owners of abutting properties, extensive litigation ensued during the course of receiving approval to build the loop.^[5] Between January 8, 1894 and June 29, 1896 a series of ordinances were passed by the Chicago City Council enabling the construction of the Union Loop's route.^[5]

The Union Loop was constructed in separate sections: the Lake Street 'L' was extended along the north side in 1895; the Union Elevated Railroad opened the east side along Wabash Avenue in 1896 and the west side along Wells Street in 1897; and the Union Consolidated Elevated Railroad opened the south side along Van Buren Street in 1897.

The Loop opened on September 6, 1897.^[6]

The Loop was born in political scandal: upon completion, all the rail lines running downtown had to pay Yerkes's operation a fee, which raised fares for commuters; when Yerkes, after bribery of the state legislature, secured legislation by which he claimed a fifty-year franchise, the resulting furor drove him out of town and ushered in a short-lived era of "Progressive Reform" in Chicago.^[7]

Originally there were 12 stations, with three stations on each side. The construction of the west-leg of the Union Loop over Wells Street required the removal of the southern platform of the Fifth/Lake station. The addition of the Northwestern Elevated Railroad caused the removal of the rest of the station as the remaining platform sat across the new road's entry point.^[8] This left 11 stations, two on the north leg of the loop and three on each other leg.

Development of the Loop (diagrams)

1895–1897	1897–1900
Legend Clark/Lake Chicago River Chicago River Fifth/Lake State/Lake Randolph/Wabash Madison/Wabash Adams/Wabash	Legend Clark/Lake Chicago River Chicago River Fifth/Lake State/Lake Randolph/Fifth Randolph/Wabash Madison/Fifth Madison/Wabash Adams/Wabash Quincy State/Van Buren Pacific/Van Buren Dearborn/Van Buren
1900–1913	1913–1931
Legend Chicago River Chicago River Clark/Lake State/Lake Randolph/Fifth Randolph/Wabash Madison/Fifth Madison/Wabash Adams/Wabash Quincy State/Van Buren Pacific/Van Buren Dearborn/Van Buren	Legend Chicago River Chicago River Clark/Lake State/Lake Randolph/Wells Randolph/Wabash Madison/Wells Madison/Wabash Adams/Wabash Quincy State/Van Buren LaSalle/Van Buren Dearborn/Van Buren
1931–1949	1955-1958
Legend Chicago River Chicago River Clark/Lake State/Lake Randolph/Wells Randolph/Wabash Madison/Wells Madison/Wabash Adams/Wabash Quincy State/Van Buren LaSalle/Van Buren Dearborn/Van Buren	Legend Chicago River Chicago River Clark/Lake State/Lake Randolph/Wells Randolph/Wabash Madison/Wells Madison/Wabash Adams/Wabash Quincy State/Van Buren LaSalle/Van Buren
1958–1969	1969–1993
Legend Chicago River Chicago River Clark/Lake State/Lake Randolph/Wells Randolph/Wabash Madison/Wells Madison/Wabash Adams/Wabash Quincy State/Van Buren LaSalle/Van Buren	Legend Chicago River Chicago River Clark/Lake State/Lake Randolph/Wells Randolph/Wabash Madison/Wells Madison/Wabash Adams/Wabash Quincy LaSalle/Van Buren State/Van Buren
1993–1997	1997–present
Legend Chicago River Chicago River Clark/Lake State/Lake Randolph/Wells Randolph/Wabash Washington/​Wells Madison/Wells Madison/Wabash Adams/Wabash Quincy LaSalle/Van Buren	Legend Chicago River Chicago River Clark/Lake State/Lake Randolph/Wabash Washington/​Wells Washington/​Wabash Madison/Wabash Adams/Wabash Quincy LaSalle/Van Buren Library

This lists each station beginning at the northwest corner and moving counterclockwise around the loop: south along Wells Street, east along Van Buren Street, north along Wabash Avenue, and west along Lake Street.

Station	Location	Notes
Randolph/Wells	150 N. Wells St.	Closed July 17, 1995; partially demolished and replaced by Washington/Wells
Washington/​Wells	100 N. Wells Street
Madison/Wells	1 N. Wells St.	Closed January 30, 1994; demolished and replaced by Washington/Wells
Quincy	220 S. Wells Street
LaSalle/Van Buren	121 W. Van Buren Street
Dearborn/Van Buren	Dearborn Street and Van Buren Street	Closed 1949; demolished, replaced by Harold Washington Library-State/Van Buren on June 22, 1997.
Harold Washington Library – State/Van Buren	1 W. Van Buren Street
Adams/Wabash	201 S. Wabash Avenue
Madison/Wabash	2 N. Wabash Avenue	Closed March 16, 2015, demolished and replaced by Washington/Wabash.
Washington/​Wabash	29 N. Wabash Avenue	Consolidation of Madison/Wabash and Randolph/Wabash, opened August 31, 2017.
Randolph/Wabash	151 N. Wabash Avenue	Closed September 3, 2017; demolished and replaced by Washington/Wabash.
State/Lake	200 N. State Street
Clark/Lake	100 W. Lake Street, Chicago
Fifth/Lake	Wells Street and Lake Street	Closed December 17, 1899; demolished

• Chicago Central Area Transit Plan
• History of the Loop (CTA)
• Wells Street Terminal

• Historic American Engineering Record (HAER) No. IL-1, "Union Elevated Railroad, Union Loop", 30 photos, 1 measured drawing, 25 data pages, 3 photo caption pages
• Loop Elevated at Chicago-L.org

41°52′48″N 87°38′47″W / 41.88000°N 87.64639°W / 41.88000; -87.64639