An interim report has confirmed a runaway coal train reached speeds well in excess of the safe limit and rolled backwards for 5 kilometres before coming to a halt.

In short:

A runaway coal train had no-one on board as it travelled 20 kilometres through the Hunter Valley on July 25.

An interim probe has found it reached speeds of up to 90 kilometres an hour as 96 wagons hurtled along the track.

What’s next?

A final report will be tabled in the NSW parliament.