A train car went off the rails and ended up in a creek in Northern California on Monday night, according to the Alameda County Fire Department.
Nine people were hurt when the train struck a tree that had fallen into the middle of the tracks. Four of the injuries were described as "serious" but not life-threatening.
Authorities earlier reported that 14 people had been injured.
"The train flipped over, and then I saw people, you know, falling over from the other side," passenger Jay Vijayen told CNN affiliate KGO. "The next thing we knew, we started seeing water coming into the bottom of the train. It was rising fast."
All of the passengers from the derailed train have been removed, authorities said.
"I've never seen anything like this," said Sgt. J.D. Nelson with the Alameda County Sheriff's Office. "It was absolutely chaotic."
The ACE train, which runs from Stockton to San Jose, derailed near Niles Canyon, the company said. Train service has been canceled for Wednesday.
According to Steve Walker, a spokesman for Altamont Corridor Express, the lead car on the train derailed and ended up in the Alameda creek after the initial crash. The second car also derailed but remained upright, he said.
There were 214 passengers on board.
"ACE Train's No. 1 priority is passenger safety," Walker said.
The Fremont Police Department said it expected roads in the area to remain closed for several hours.