There was a UP freight derailment, as reported by Robert Salonga of the Contra Costa Times:

East Bay Amtrak service delayed until afternoon
By Robert Salonga
STAFF WRITER
Amtrak train service in the East Bay will involve cancellations and delays until this afternoon while crews repair the weekend derailment of a freight train, company officials said.
A Union Pacific freight train derailed Sunday west of the Martinez train station, causing the railroad, which owns the tracks, to temporarily close off train access between Richmond and Martinez, according an Amtrak statement issued this morning.
The derailment occurred around midnight this morning, said Contra Costa County Sheriff’s Lt. Jeff Hebel.
No one was injured, and the three tankers the train was pulling were empty, so there was not spillage of hazardous materials, Hebel said. The train cars came to rest on top of a jet fuel pipeline, which was quickly depressurized to eliminate any danger. The cause of the derailment is under investigation.
As a result, Capitol Corridor passengers will be bused between Richmond and Martinez until the track is re-opened this afternoon.
Amtrak trains on the San Joaquins line starting in Oakland will detour between Antioch and Emeryville, and skip its Richmond and Martinez stops.
The eastbound California Zephyr line will skip Martinez and Davis stops, taking a detour in Stockton on the way to Sacramento. Passengers in the skipped stops will be provided transportation to reconnect with the train in Sacramento.
The southbound Coast Starlight will be temporarily suspended and passengers will instead be bused from Sacramento to Oakland, where they can reconnect with the train.
Passengers who use any of the affected services can call 1-800-USA-RAIL for the latest train status updates.