On the night of 24 September 1905 a railway inspector walked through the Merstham Tunnel in Surrey to make a routine inspection.
He might have been checking for obstructions on the line, or whether the tracks were in good repair, but what he found was the dead body of a young woman.
Mary Money, 21, had met a gruesome end in mysterious circumstances that are still unsolved to this day.
Former Merstham Society chairman Chris Green told
Secret Surrey: "The local GP, Dr Cricket, came out and confirmed that she [Money] was dead...and later on did the autopsy and that revealed rather unsettling facts."
Despite initial theories that she had potentially walked into the tunnel to take her own life, Green said it began to "look more and more that she'd been pushed out" of the train.
A key revelation was the finding that "a foot" of a silk scarf Money was wearing had been stuffed into her mouth.
Another was that all signs indicated she had "hit the tunnel going out backwards of the carriage".
Money, from Surrey but living in London, was spotted on the 21:12 BST service from London Bridge to Brighton on the night of her death - and she wasn't alone.
The train guard saw her with an unknown man, and when the train stopped at East Croydon he observed that they "deliberately turned away as if they didn't want him to interfere".
According to Green, the man "made a dash for the exit" at Redhill.
"There was no sign of any woman," he said.
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