The CTA is installing 4 cameras capable of panning 360 degrees to some of the old rail cars.
Officials said the cameras have assisted police in the arrest of more than a dozen suspects.
"We're already seeing what impact cameras on all CTA rail cars will have in deterring crimes and assisting police in the apprehension of those committing crimes on and off our system," CTA President Forrest Claypool said in a press release.
It is a part of the city's plan to improve the CTA.
"Having a world-class public transportation system is a key goal of my administration, and making sure that Chicagoans can have a safe experience on board our trains and buses is a top priority," Mayor Emanuel said in a press release. "These additional cameras will work directly with the many other upgrades we've made to improve the experience of our passengers, so they can get to work and school smoothly and safely."
Newer rail cars already have cameras installed in every car, according to the CTA.