While fuel was leaking from the derailed train, there were no other hazardous-materials threats, according to the San Bernardino County Fire Department.
There were no passengers on the train.
The derailment was reported around 8:30 a.m. in the area of Kelso Cima and Kelbaker roads in the desert near the ghost town of Kelso, east of Barstow.
The southbound Union Pacific cargo train was carrying 55 railcars and two locomotives. Train officials say the iron ore is used in the steelmaking process and is not considered a hazardous material.
No crew injuries were reported. Officials are declining to comment on reports the crew jumped off the train before it derailed.
The cause of the derailment is being investigated.