KiwiRail's freight services between Auckland and Wellington are running again after a derailment earlier this week damaged the tracks.
One person received minor to moderate injuries after a train, carrying a load of containers through Waipa, near Hamilton, struck a vehicle on Monday at a rail crossing.
A crane had to be brought in to lift the locomotive and wagons and required repairs to the track meant freight services between Auckland and Wellington were paused.
But the North Island Main Trunk Line reopened at 4am on Wednesday.
A KiwiRail spokesperson said while scheduled freight services were running again, there was still a backlog, and they expect to clear it over Wednesday and Thursday.