Commenter Wrote:
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> Since mine carts tended to be produced locally
> their gauge varied widely. Here is an extract from
> a text (1907) on mine carts. It mainly concerns
> coal and iron mining but it has more detail and
> mathematics than most will require. It mentions
> gauges from 18" to 39-1/2", but they are just
> examples.
>
> [
books.google.com]
> ntsec=frontcover&dq=isbn:098165262X&hl=en&sa=X&ved
> =0ahUKEwiRx5L_sbjjAhWYIjQIHTm6DZ0Q6AEIKjAA#v=onepa
> ge&q&f=false
Thanks for the link, I ordered a copy from Jeff Bezos ;)