Rock Slide Delays Amtrak in Calif.

The slide occurred just before dawn about 25 miles northeast of Oakland. It initially covered both tracks, which carry 57 trains a day through the region, said Mark Davis, spokesman with Union Pacific Railroad.

A crew cleared the debris from one of the tracks, allowing trains to alternate moving east and west at a reduced speed.

By 8 a.m., four Amtrak commuter trains were delayed, and more would probably run late as work progressed throughout the day, said Karina Romero, an Amtrak spokeswoman.

"Something like this early in the morning causes a domino effect," said Romero.