About 15 small fires stretched up the train line from Woods Cross to Layton on Thursday afternoon, contributing to a smoky drive on I-15.
Firefighters from South Davis Fire District, Farmington and Kaysville battled blazes that were caused by a passing train.
"I don't know what the malfunction was on that train, but it definitely caused a few fires," South Davis Chief Brent Argyle said.
Firefighters were able to contain and mop up the blaze in about an hour — finishing up at 3:30 p.m.
Argyle said the fires wouldn't have caused any significant damage because they were located between the railroad tracks and I-15.
He said at times it was impossible to tell which smoke was from the Davis County fires and which was from the Cascade Fire, burning southwest of Midway, Wasatch County.