An spokesperson for the agency tells us an Oakland-bound San Joaquin train from Bakersfield hit the vehicle at about 2:45 p.m.
The crash happened near Orwood Road, east of Brentwood in East Contra Costa County near the San Joaquin County line.
The truck came to a rest submerged in a river located adjacent to the railroad crossing.
Sky7 HD captured video showing one of two medical helicopters taking off with the crash victims.
Aamtrak says that 139 people were onboard, but no injuries were reported on the train.
It came to a stop after hitting the vehicle. Its journey to Oakland has been delayed.