The driver was the only occupant of the van to survive and was taken by helicopter to a Houston hospital, where he was in critical condition Thursday night.
The driver, 25, will be charged with three counts of manslaughter, Harris County Deputy Jeremy Thomas said. The driver steered around a crossing arm to try to beat the train, authorities said.
"This is about as reckless as you get," Thomas told the Houston Chronicle on Friday. "In an accident like this, with the recklessness of his actions, this is the most appropriate charge."
The van's driver allegedly followed another car that also ignored the signal. "Apparently whoever was driving the van thought it was safe to continue across the tracks," Lt. John Martin of the Harris County Sheriff's Office told The Associated Press. "They just followed the car and then got hit by the train."
There were no reports of injuries on the Union Pacific train. The accident occurred in the Houston suburb of Spring.