Amtrak spokeswoman Vernae Graham says several people on the train suffered "minor to moderate injuries." She said she did not know the exact number of people hurt, but said many suffered only bumps and bruises.
Graham did not know how fast the train was going at the time of the collision. The driver of the truck was not hurt and the train did not derail after the crash.
Graham says the southbound Amtrak San Joaquin train No. 718 hit the tractor trailer around 7:30 p.m. east of Antioch.
Graham says the train departed from Oakland at 5:50 p.m. and was bound for Bakersfield.
The Associated Press contributed to this report.