The vehicle belonged to a commercial haulier and the driver was not a member of the military, officials said.
The train had been travelling from Dunkirk to Paris when the collision occurred and it continued moving for several hundred metres before coming to a stop.
CEO of France’s state-owned rail operator, Jean Castex, confirmed the train driver had been a 56-year-old long-term employee of the company at a news conference on Tuesday.
“My first thoughts go to his family, his loved ones and colleagues,” he said.
“I also want to pay tribute to the two train staff members who were on board and who calmly stepped in and helped the passengers.”
Castex, also a former French prime minister, said there had not been any indication of any problem with the barriers at the level crossing, adding that a lower-speed train had passed through minutes earlier.
The region’s President Xavier Bertrand described the accident as a “terrible tragedy”.