Saturday 15th July 1967 the up North Briton was derailed by a broken rail.
Picture shows the broken rail (1941 single hole rail) A 202 squadron helicopter was used to ferry the nine injured persons to ambulances at nearby RAF Acklington.
I have the official accident report and this is the photo page included with it.
The online pdf of the document I have is also available here -
http://www.railwaysarchive.co.uk/doc....php?docID=420