The train derailed at a crossing in Clinton, Otago.

A Balclutha couple's drive to get a Friday night treat from KFC in Gore was postponed when a freight train derailed before their eyes at Clinton.

Chris and Leah-Anne Bunting were third in a queue of cars waiting at a level railway crossing at the South Otago town's southern end.

Chris Bunting said he'd never seen or heard anything quite like it.

JIMMY PATON The freight train was thought to be travelling north.

"I heard this hollow sound, then this dragging sound of metal over gravel, and then all the carriages started to wobble."

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It was like "a domino effect", as the wagons derailed, he said.

Supplied Several wagons were still on the rails, the witness said.

The couple said the train appeared to have snapped as it went over the railway crossing, leaving two wagons on the southern side, while the engine and the other wagons continued on the northern side, before coming to a stop.

"We were in shock," Leah-Anne Bunting said.

"We couldn't quite believe what we were seeing."

SUPPLIED No one has been injured, police said.

She placed a 111 call at 7.34pm, just after the derailment occurred. The scene rapidly filled with spectators and emergency services.

Emergency services rushed to the incident in Clinton, but there were no injuries.

Kiwirail said in a statement that six wagons of a freight train travelling north from Invercargill derailed at Clinton, between Gore and Balclutha, at about 7.30pm.

MARY-JO TOHILL/FAIRFAX NZ Two derailed wagons on the south side of Clinton's level railway crossing, following a derailment on Friday night.

The 800-metre-long, 2000-tonne train heading towards Dunedin when it derailed.

The rear of the freight train had left the tracks, a Fire Service spokesman said.

"It's a significant derailment. It will take a while to clear," he said.

MARY-JO TOHILL/FAIRFAX NZ Two derailed wagons on the south side of Clinton's level railway crossing, following a derailment on Friday night.

Chris Bunting, who works for rural service company Advanced Agriculture, and was familiar with the Clutha District, said he'd experienced a derailment at Warepa, further north on the railway line, about two years ago.

"My first thought was for the train driver, so we swung and went to pick him up."

They found him at Hillfoot Rd, just off the State Highway, near the Clinton Rugby Club, about 600 metres north of the level crossing.

MARY-JO TOHILL/FAIRFAX NZ The last of the north bound wagons, which partially blocked State Highway 1 at the Clinton level railway crossing. Two wagons snapped off from the train, and were left at the crossing's southern end.

The train driver himself declined to comment about the incident.

However, the Buntings said when they reached him, he was on the radio telephone, following safety procedures.

"He said he didn't know what had happened, but had felt a tug."

The end wagon on the level crossing's northern side is slightly overhanging the south bound lane, but not blocking it. Emergency services, including Clinton Fire Brigade, had cleared the highway by about 9.15pm. The two completely derailed wagons to the south are resting on their sides and off the tracks.

Workers at the scene said they would be further investigating the matter on Saturday morning.

The Buntings said they were able to carry on to Gore, about 30 minutes south of Clinton, for their meal, but had looked in on the incident on their way back to Balclutha.

It is expected that the derailed wagon, which is on the southern side of the crossing, will be cleared from the line tomorrow