Thick black smoke billowed into the air after a train derailed in the US state of Iowa, prompting authorities to evacuate part of a nearby town.

The fiery derailment happened around 2:00pm Sunday on the south-west edge of Sibley, a town of about 3,000 people roughly 320km north-west of Des Moines.

There were no immediate reports of injuries related to the derailment.

Photos and video of the derailment show dozens of train carriages piled up along the tracks with flames and a large plume of smoke coming from one end of the pile of carriages.

Authorities reportedly evacuated an area within 8 kilometres of the derailment.

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Union Pacific spokeswoman Robynn Tysver said about 47 carriages came off the tracks during the derailment, but the train crew was not injured. She said the railroad is working with local authorities.

Ms Tysver said the cause of the derailment is under investigation.

Sibley Fire Chief Ken Huls said the train was hauling fertiliser and ammonium nitrate.

About 2,750 tonnes of ammonium nitrate exploded and killing more than 200 people in August last year after being stored improperly in Beirut, Lebanon.

Nate Minten said smoke was still visible around 4:30pm Sunday from his mother's home.

"We didn't hear any bangs or anything."

AP