SU3368 : Train wreck at HungerfordThis crash was caused by a defective axle bearing on one of the stone wagons. It part demolished the signalbox, which was replaced with a newer style box, still operating semaphore signals, and which lasted into resignalling in the 1980s.
The signalman, Robbie Bowden, was standing on the lever frame, on the operating floor of the 'box, communicating with colleagues up the line, when the crash occurred, and he was quite seriously injured.
For more reading, I suggest "Signalman's Nightmare" by Adrian Vaughan