A Dutch metro train was saved from disaster when it smashed through a safety barrier but was prevented from plummeting into water by a sculpture of a whale's tail.

The driver of the train, who was the only person on board, was unharmed in the incident which happened just after midnight at Spijkenisse, near the port city of Rotterdam. 

The front carriage was left hanging ten metres above the water, propped up only by the giant silver-coloured sculpture - called, improbably, 'Saved by the Whale's Tail'.

"The metro went off the rails and it landed on a monument called Saved by the Whale's Tail. So that literally happened," Carly Gorter of the Rijnmond regional safety authority said.

"Because of the whale's tail the driver actually was saved, it's incredible."

The driver was later held for questioning, the safety authority said. The cause of the crash was still being investigated.

The sculpture was built around 20 years ago in a park underneath the raised metro, its name a deliberate play on the fact that it is a "tail track" at the end of the line.

It features two large whale tails poking out of the water, one of which saved the train.

A team of experts, including the architect of the sculpture, was on site to work out how to safely remove the train.

"The problem is it's water around it, so a crane isn't able to get there," said Carly Gorter of the Rijnmond regional safety authority.

"We have a lot of wind at the moment and that's one of the issues that we're facing, that's a risk and worry."