Sparks from a train appear to have caused a string of bushfires in Perth's Swan Districts, with flames leaping up to four metres high.
An emergency warning was issued early on Thursday afternoon for residents near Shady Hills in Bullsbrook after several fires broke out in the area.
With homes under direct threat, residents have been urged to leave if the way is safe.
Several out-of-control blazes have also broken out in the nearby Walyunga National Park in the Darling Range.
Department of Fire and Emergency Services spokesman Allen Gale said the fires were about 2km apart and were close to joining up.
Mr Gale said the fires had erupted along a train line around the same time, so while the cause of the fire was being investigated, it could have been triggered by a sparking train.
A News Ltd report cited a witness who had seen a Kalgoorlie-bound freight train with smoke pouring out from underneath it.
It is believed rail lines to and from Northam in Perth's east have been shut.
"It's up in quite steep terrain," Mr Gale told AAP.
"The fire has raced up the hill and it always travels much faster uphill."
Water bombers are assisting ground crews.
Relocation points have been set up at Bullsbrook Recreation Centre and Swan Park Leisure Centre.