"4square" wrote in message
oups.com...
A pal of mine is a keen railway modeller, and we have often wondered,
how the scale for 'O'- gauge ever came to be set at 7 mm to the
imperial foot. The track gauge is 32 mm, which is about right for 4
feet 8.5 inches. Anyone any ideas?


http://www.rsme.org/Features/Rsme-history.htm
gives a clue - the standardisation to one and a quarter inches between the
rails - to accommodate different manufacturers products.

Hugh