Chicago "L"
Renovation and expansion plans
In late 2007, trains were forced to operate at reduced speed over more than 22% of the system due to deteriorated track, structure, and other problems. By October 2008, system-wide slow zones had been reduced to 9.1% and by January 2010, total slow zones were reduced to 6.3%.[citation needed] CTA's Slow Zone Elimination Project is an ongoing effort to restore track work to conditions where trains no longer have to reduce speeds through deteriorating areas. The Loop received track work in 2012–2013. The Purple Line in Evanston received track work and viaduct replacement in 2011–2013. The Green Line Ashland branch received track work in 2013, prior to the Red Line Dan Ryan branch reconstruction.
Chicago "L"-37