The train driver involved in a fatal crash with a school bus on Wednesday morning sounded his horn in warning before the collision, KiwiRail says.
The crash occurred just after 8am at the intersection of Railway Road and Cleverly Line in Bunnythorpe, north of Palmerston North.
KiwiRail Group chief executive Greg Miller said the train involved had been travelling from Palmerston North to Whanganui to collect log wagons.
The train's driver was the only person on board.
Flashing lights and bells went off at the intersection as the train approached the crossing and the driver told Miller he sounded his horn in warning.
The bus, which was carrying children to Feilding High School, collided with the train and the bus driver died at the scene.
Another 40 patients were assessed with conditions varying from moderate to minor and six were transferred to Palmerston North Hospital.
Miller said KiwiRail was deeply saddened to hear of the crash.
"I send my thoughts, and those of all our KiwiRail staff, to the whānau and all those affected," he said.
"We are supporting our train driver, who is shaken but physically unharmed."
The train received minor damage in the crash.
Miller said there had been no collisions at the Clevely Line level crossing in the last 15 years, although there was one near miss when a car crossed in front of a train in January 2011.
The line speed for trains travelling through this area is 80km/h.
KiwiRail has now closed the line and will reopen once they get clearance from other agencies and have completed safety checks.
"Three freight trains are currently being held back while the line is closed, and we are in contact with affected freight customers," Miller said.
"KiwiRail will be offering support to the schools involved and the bus company."