The cause of Tuesday's derailment of a train in County Londonderry is not in dispute, Regional Development Minister Peter Robinson has said.

He visited the site at Downhill near Castlerock on Thursday night.

It is understood the minister will receive details of an investigation into the accident by public transport operating company Translink before addressing the assembly on the accident.

Twelve people, including the driver, were hurt when a train from Londonderry was derailed after hitting a boulder that fell on the track in a landslide.

Peter Robinson: Visited the site at Downhill

Mr Robinson said the cause of the accident was not disputed.

"This is not an issue. Like many major cases we have had in Great Britain, where there is doubt why a derailment took place, this is not a case of having to guess why it occurred.

"It is clear the only issues are if there is any predictability about it or if it could have been stalled in some way," he said.

The accident is believed to have been caused by a landslide.

The train driver and passengers were injured when the 1250 BST Londonderry to Belfast train came off the line as it was approaching the Downhill tunnel near Castlerock on Tuesday.

Translink's Ciaran Rogan said there would be a thorough investigation into the accident.

The carriages were thrown onto an adjacent road

A police spokesperson said recent heavy rain was believed to be responsible for the landslide which saw rocks and boulders land on the track and two adjacent public roads.

The train was approaching Downhill when the driver saw a boulder on the track. He applied the emergency brake, but could not stop the train in time.

Leg injuries

Twenty-one people, including the driver, were on board the three carriages when they were derailed.

The driver, who was the most seriously hurt, was treated for leg injuries.

One of the carriages was forced onto the beach adjacent to the track.

Among those taken to hospital were five people suffering from angina.