Southbound MARTA trains were being delayed Friday morning after a mechanical problem with a train door.

MARTA spokesman Lyle Harris told The Atlanta Journal-Constitution that about 9 a.m., the mechanical problem “prevented a southbound train from pulling into the Arts Center station.”

He said that about a half-hour later, the train was able to pull into the station and offload passengers.

“As a result, MARTA is single-tracking between Arts Center and Lindbergh Center until further notice,” Harris said.