CAPE TOWN — A passenger train burst into flames on Thursday after striking two vehicles at a crossing in a remote part of central South Africa, killing at least 18 people and injuring more than 260, the authorities said.

Mondli Mvambi, a spokesman for the provincial health department, said that a truck driver had miscalculated the train’s speed and tried to dash across the tracks at the crossing, just outside the town of Kroonstad, and that a passenger vehicle had also been involved.

“The death toll may rise,” Mr. Mvambi said. “Three burned carriages are yet to be lifted to check if anyone is trapped inside. It can take 36 hours. Rescuers are working as fast as they can.”

The national transport minister, Joe Maswanganyi, told news outlets that the truck driver had been taken to the hospital. “We are going to do a blood test to verify if he was sober or not,” Mr. Maswanganyi said.

Mr. Mvambi said the truck driver, though injured, had tried to run away after the accident but had been apprehended by the police and escorted to the hospital.