Waitaki principal rural fire officer Steve Couper said fires were reported near Herbert, at Moeraki and near Palmerston, about 10am.
Two appliances each from fire stations at Palmerston, Weston, Kakanui and Hampden attended the fires and it took about an hour and a-half to quell the flames.
Mr Couper said the fires had all taken place in rail corridors.
''It looks like there has been a problem with a train and it has set fire to undergrowth.''
A helicopter had carried out aerial reconnaissance to ensure there were no unreported fires, he said.
A KiwiRail spokeswoman confirmed the fire was caused by sparks coming from a southbound freight train on its way to Dunedin, after the brakes jammed on one of its locomotives.
The train driver stopped in Palmerston and continued to Dunedin powered by the train's other locomotives, after leaving behind the faulty one.
A KiwiRail serviceman would travel to Palmerston to repair the locomotive today, she said.
A Herbert resident, who wished to remain anonymous, said he had seen flames coming from the undercarriage of a freight train before two fires started, near Bluff Hill Rd and Frame Rd.
''The third engine was belching flame.
''The fire was at the bottom. It looked like it was diesel, I would have thought. It had quite a good flame on.''
