I was told about that happened in the 1960's when all the steam trains were being withdranwn. Apparently all the locomotives would be drawn up in a line to be towed away for scrapping and the train spotters were out taking numbers as they left ..... meanwhile at the other end of the line, other spotters were also taking numbers, but when numbers were compared somtime later there were large batches missing.
It later transpired that the regular drivers who took these trains would find their shift was cancelled but the trains still went but nobody knows who took them ...the theory was that they'd been taken for storage in case of a nuclear war when diesel and electric trains would be useless.
The funny part was, in the 80's where we were working, some blokes were about to start demolishing a water tower by the side of a rail track on private land, that was till two blokes turned up and informed the demolition lads that they couldn't be touched even though they were no longer in use. hmmmmm

WAS IT TRUE AFTER ALL...?