BART trains headed into San Francisco on the Pittsburg/Bay Point line continue to run about 20 minutes behind schedule this morning due to an earlier problem, a spokesman said.
At about 4:45 a.m., a train traveling west near Walnut Creek encountered a metal object on the tracks, which caused it to lose power and brake in place, BART spokesman Linton Johnson said.
It was not clear what the object was, Johnson said.
Passengers on the disabled train were transferred to another, and crews were on the scene at 6:30 a.m. working to remove the disabled cars from the tracks.
Other BART lines are not affected by delays this morning.