Man's arm severed in NT train accident

A man has lost his arm after trying to jump onto a moving train in the Northern Territory.

The 25-year-old may have been trying to hitch a ride into Alice Springs from the town's southern suburbs when he jumped onto the freight train at 9.25pm on Thursday night, police say.

He fell onto the tracks and severed his arm, but the train driver was unaware of the incident.

St Johns Ambulance spokesman Craig Garraway said the man underwent surgery at Alice Springs Hospital last night on his left arm.

"The lower part was amputated on scene. The upper part was quite severely injured and they may have looked at amputating it just below the shoulder," he told AAP.

"There's a chance he may be flown onto Adelaide by the Royal Doctor service."

NT Senior Sergeant Michael Gilby said the man's friends waved down a passing tourist for help after the accident.

"They called police and ambulances so we were able to get there very quickly," he told ABC local radio.