In a 4:23 p.m. tweet, CTA said that trains were running again with residual delays. The deer was on the tracks at Rosemont station.
"Bambi is alive," according to a Chicago Fire Department tweet.
The deer was taken away by animal control, the fire department said. Freeing the deer required the efforts of multiple local and state agencies, a CTA spokesman said.
CTA first tweeted that the deer was on the track at about 1:20 p.m., suspending service between the O'Hare and Harlem stops on the city's Northwest Side.
Service continues to be disrupted while we work with local authorities to address and restore service. We also continue to work to institute full bus shuttle service, but also encourage riders to consider alternatives to Blue Line between Harlem & O'Hare at this time. https://t.co/GZIj9fMz0R— cta (@cta) November 12, 2018
CTA was working to bring bus shuttle service to riders, but encouraged alternate routes.
The Chicago Fire Department was assisting with the deer, according to a tweet.
Cta service interrupted on blue line. CFD assisting with deer on tracks.— Chicago Fire Media (@CFDMedia) November 12, 2018
Sun-Times Media Wire contributed to this report.