The driver of the truck was a Ventura County Public Works Agency employee who was providing dust control to nearby workers at the time of the collision on Wednesday morning, according to investigators. The crew was cleaning up a debris basin.
Why the vehicle was in the path of the train, which had about 200 people onboard, remained unclear.
The crash occurred shortly before 11:30 near Los Angeles Avenue and Gabbert Road. Several of the train cars were dislodged from the tracks but all of them remained upright.
Amtrak train partially derails after water truck obstructs tracks in Moorpark; 16 injured
Sixteen people were transported to a hospital after the collision. The train occupants sustained minor injuries, while the driver was taken to a trauma center.
On Thursday afternoon, crews were seen installing new tracks at the crash site as train service remained suspended.
Oxnard resident Ricky Williams, who commutes to downtown Los Angeles, said the trip usually takes him an hour and 40 minutes on the train. On Thursday he was forced to drive to the Moorpark station, which lengthened his commute to more than two hours.
"For me, it's not frustrating at all because I've been doing this for over 10 years," Williams said.
No estimate has been given by Amtrak of when train service will resume at the location.
The crash is being investigated by the National Transportation Safety Board.