Fallen branches injured a Chicago Transit Authority train operator and delayed the Yellow Line for about two hours Monday morning, officials said.

Evanston fire officials responded to a call at about 7:20 a.m. to a westbound train at Asbury Avenue and Mulford Street, Division Chief John Brewer of the Evanston Fire Department said.

The 25 passengers aboard the train were not injured and were transferred to a train headed back to the Howard Street station, CTA spokeswoman Ibis Antongiorgi said.

Fire officials worked from about 7:30 a.m. to 8 a.m. and had to walk about 60 feet down a hill to reach the victim because the train, known as the Skokie Swift, operates below street level, Brewer said.

The train operator was injured on his right side after debris from the tree hit the windshield of the train. After fire officials stabilized the victim, he was taken to St. Francis Hospital in Evanston, Brewer said.

“A tree branch coming through a train or a car is not something you hear about everyday, ” Brewer said. “It’s one of those freak accidents that just happens.”

Service to the Yellow Line was back on track by 9:31 a.m., Antongiorgi said. Officials did not know whether high winds caused the branches to fall, but the winds affected power wires above the train and increased the delay, Antongiorgi said.