No trains were involved in the incident, and no one was injured. However, trains had to be diverted out of the subway to the elevated tracks.
The fire department says the fire started when maintenance materials ignited in the subway near the Clark and Division station.
Over a dozen firefighters arrived after a 211 alarm was called as a precaution. Crews arrived to find at least one large fire on the tracks.
The blaze was quickly put out as emergency workers vented the subway of smoke.
"The fire was small and retained. It produced a lot of smoke. In the subway, it becomes a panic situation. Our concern was for the passengers. No reports whatsoever," said 1st Chief John Nokes of the Chicago Fire Department.
That wasn't the case in July 2006 when a fire on the CTA's Blue Line during a weekday evening commute forced riders to evacuate. Some 152 people were taken to a dozen hospitals.
Some officials said no one was hurt in Saturday's incident, probably, because it happened over the weekend.
One cheese vendor at a Farmers Market near the fire site was happy her product was possibly the only catastrophe.
"We have a perishable project. At least it didn't happen at 9 a.m. or something," said vendor Celeste Peterson.
Fire officials say that they made quick work of the blaze simply because the agencies responding to the emergency were able to communicate effectively, obviously something they have learned from past experiences.