Putting Rapid back in Transit
At CTA, track renewal work continues in order to remove and prevent slow zones on the 'L' system.
Slow zones are areas where trains are required to operate at slower-than-normal speeds due to track conditions. Slow zone elimination work typically involves replacing aging rail ties and tie plates with new ties and plates, if not whole track replacement.
The end result of this construction is faster and more reliable service and a better, more comfortable commute.
(See the FAQ below for more about how tracks are laid.)
Looking for slow zone maps?
You can view the latest and archived maps showing where slow zones are in place on the 'L' system from the Slow Zone Maps page.
Latest Project Information
Red and Purple Lines: North Side Main Line (Belmont to Howard)
Work to eliminate slow zones on the North Side continues, including in the area of the Sheridan and Wilson stations, as well as on the express tracks from Belmont to Howard that are used by Purple Line Express trains during rush periods.
Work was completed in the area of Sheridan station in late 2009, with slow zones removed in this area in December and work completed in January 2010.
This work will continue throughout 2010 and will eliminate approximately 6,000 feet of slow zone on the North Side Main Line.
More Information
See the Red Line and Purple Line Route Guides for route information and all posted customer alerts for these routes.
Orange Line
CTA implemented temporary slow zones along the Orange Line in April 2010 as a preventative measure due to issues with the signal system on that route. Trains traveling on the Orange Line between Midway and Roosevelt are operating at no more than 35 mph while repairs are made to the signaling system along the line.
CTA has a thorough maintenance and safety system in place and while performing inspections along the Orange Line, a potential defect with a component of the signaling system was discovered. While the chances of the defect actually occurring are extremely rare, CTA has implemented additional safeguards until the signaling fault is properly addressed. CTA engineers have a proposed solution and are reviewing it with the manufacturer.
Other Routes
As a part of regular maintenance, the CTA inspects, detects, and repairs conditions that might require slow zones. CTA also performs “tamps” the tracks, a maintenance activity that realigns track and stabilizes the ballast supporting the tracks, on a regular and ongoing basis to help prevent slow zones from forming due to track deterioration.
What we've already done
CTA has drastically reduced the number and coverage of slow zones in recent years, thanks to an ambitious programs to renew and replace aging and deteriorating components of the 'L' system. The most recent of these projects is the Dearborn Subway Track Renewal Project.
Dearborn Subway Track Renewal Project (Blue Line)
Slow zone elimination in the Dearborn Subway began during 2007 and 2008, when track tie replacement and other improvements were made between the Dearborn Subway's north portal (located between Damen and Division) and Clark/Lake to eliminate existing slow zones that were substantially impacting travel times. Using the resources available, construction crews focused on the sections of track that were in the worst shape.
A larger project funded by the Federal American Recovery and Reinvestment Act during 2009 and early 2010 upgraded tracks and track ties along the full length of the Dearborn Subway, from Damen to UIC-Halsted.
Many track components in the subway, including aging track ties, were replaced to provide even more reliable service in the future.
Dearborn Subway Project Overview
The $88 million project will result in the renewal of approximately 39,000 feet of track in the Blue Line Dearborn Subway. Funding is being provided by the Federal American Recovery and Reinvestment Act, and will create approximately 400 jobs over the course of the work (see Press Release).
This work will replace the remainder of older wooden track ties and replace them with new concrete ties to eliminate any remaining slow zones and prevent future slow zones. The goal of the project is to ensure better service and reliability, both now and in the future.
Work began in April 2009, with the bulk of construction occurring on weekends through the end of the year. On some weekends, trains may experience delays due to construction, or train service may be replaced with bus service for the portion of the route where construction is occurring. Some work will continue through the first quarter of 2010 with less customer impact.
Stay informed. Whenever work is being done, Customer Alerts will be posted on the 'L' system and online. We encourage you to plan ahead and check the Blue Line Route Guide's Customer Alerts section for both current and upcoming events affecting service.
Project Progress
Work was undertaken in three phases, focusing on distinct sections of the subway, beginning from the north portal near Division/Milwaukee working south through to the south portal near the intersections of Interstates 290 (Eisenhower Expressway) and 90/94 (Kennedy, Dan Ryan Expressways).
Work was completed in the tunnels through Grand station during August 2009, near the Clark/Lake station toward the end of August, and finally through UIC-Halsted in December. Additional work, including new third rail, concrete and footwalk repair, grouting and sewer cleaning was substantially completed in March 2010.
Other recent improvements
Slow zone elimination work has been completed on several parts of the ‘L’ system as part of several other larger project zones, including:
- Red Line, State Street Subway in the area between north portal of the State Street Subway (north of North/Clybourn) and Roosevelt. Almost 3.5 miles of slow zones were eliminated until completion in 2008.
- Red Line, North Side Main Line from Howard to Belmont. Partial slow zone elimination was completed in 2008.
- Blue Line, O'Hare Branch between Addison and O'Hare. Track renewal and slow zone elimination work was completed in December 2008. Over 21 miles of track were renewed and over 18 miles of slow zones were eliminated.
- Blue Line, Dearborn Subway slow zone elimination between the Dearborn Subway's north portal (located between Damen and Division) and Clark/Lake. The first phase of work was completed, replacing over 5,000 deteriorated wooden track ties with concrete ties in areas where slow zones existed.
- Loop Elevated: Lake Street and Wabash Avenue sides of Loop. Slow zone elimination work was completed in November 2008.
- Brown Line, Ravenswood Branch from Southport to Western. Slow zone elimination completed October 2008 included major tie replacement work to eliminate slow zones through the elevated portions of the branch.
FAQ
Slow Zone Elimination
What goes into laying 'L' tracks?
Why are there slow zones on the 'L'?
Slow Zone Elimination
Q:
What goes into laying 'L' tracks?
A:
Railroads typically have two rails on which trains run, and are held in place by being affixed to track "ties." Ties can be made of wood, plastic or concrete. Tie plates are affixed directly to the track ties at a precise distance, and the rails are, in turn, are affixed to the ties by the tie plates.
The 'L' (like many other rapid transit systems) also has a "third rail" off to the side of the running rails, which is how electrical power is delivered to the trains.
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Q:
Why are there slow zones on the 'L'?
A:
Slow zones are created where train speeds are restricted to maintain safe travel. Commonly, this occurs in a section of track that is beyond its service life and in need of repair or replacement. Slow zones are also sometimes established temporarily in work zones over a period of ongoing construction work.
We take your safety very seriously, and continually inspect our railways for signs of deterioration. If track inspectors (or high-tech track-measuring equipment used for inspection) detect advanced wear or potential defects, a temporary slow zone may be put in place (or other, appropriate action taken), pending repair work.
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