This is from Amtrak's Train Status Page:
Due to a service disruption, we are unable to provide estimated times of departure and arrival. Please call 1-800-USA-RAIL for more information.
Train 3 from BAR to LAX for today is listed:
Estimated arrival: 9 hours and 20 minutes late.
As of the last report at 4:20 AM, at Victorville, CA, it was running 11 minutes early.
No mention of bustitution.
There is also a fire in the Simi Valley area that is disrupting the Surfliner and Starlight operations.
The sky here in Santa Barbara is thick with smoke, but no flames are visible (yet)!
Apparently the service disruption mentioned is computer-related and not fire-related.