Oops – this looks like a right purler! Now known to be an incident involving NER locomotive no 1294, it ran away on the zig zag and hit the buffers at the bottom end. The Archive’s guess that was correct, believing that the train got away on him and either the guard got his hand-brake on and the locomotive didn’t, or a wagon skipped the track and this was the result. It looks like a train of empties, so I’m surprised that the locomotive couldn’t hold it on the gradient. Looking at the collateral damage, I bet someone lost his job over this!
http://www.image-archive.org.uk/?p=46648
Possibly same accident ?
The 2 wagons standing almost vertically look to be P5 ironstone hoppers, the characteristic end brake levers are clearly visible. End brake levers were a throwback to the old Stockton and Darlington railway and perpetuated through the early years after amalgamation with the NER. The old S&D was reclassified Central Division, later still Central District and wagons often had lettered on their sides C. D. but I can’t see any on these wagons.