SAN FRANCISCO (CBS SF) — BART is reporting major delays due to a train derailment between the Balboa Park and Colma stations Saturday afternoon.

BART announced that all service had stopped between Balboa Park and Colma in the SFO, Millbrae and East Bay directions at about 2:55 p.m.

The last two cars of a nine-car Dublin/Pleasanton bound train derailed near the Daly City station and “it will be a while before we find out” the cause, BART spokesman Taylor Huckaby said.

The Daly City station was closed.

There were 24 people on board the train, but no injuries were reported.

“I heard the brakes lock up and it was really bumpy,” said one passenger, describing the moment the train derailed. “It was sorta like anti-lock brakes when they go on.”

The derailment caused smoke to fill the rear cars.

“The next thing we knew, there was smoke coming in from the back, so we were saying ‘open the doors’ and the guy on the PA system said ‘no’,” he said. “So we just had to walk over to the front of the train and wait for the smoke.”

He told KPIX 5 they had to wait about 45 minutes before they were able to get off the train.

There are reports the derailed train was cracked inside.

By 4:30 p.m. crews had cleared the southbound tracks and service to SFO resumed.

As of 5:00 p.m. crews were still working the tracks back on line.

BART announced via Twitter that several transit agencies were offering mutual aid during the track closure.

Mutual aid from @Caltrain, MUNI, and SamTrans. Bus bridge in place between Balboa Park and Daly City, and SamTrans bus ECR or 121 to Colma. — SFBART (@SFBART) May 20, 2017

BART was single-tracking trains through the area but passengers were advised to expect major delays throughout the evening Saturday. BART hopes to have the tracks back on line by Sunday’s Bay to Breakers.