Inventory / Notes / 2026-03-14
2026-03-14785 mm, and why nobody else uses it
Thirty Prussian Zoll, one Zoll of 26.154 mm, and a network that could never swap a wagon with anybody.
The Upper Silesian gauge is 785 mm because it is thirty Prussian Zoll and a Zoll is 26.154 mm. That is the whole explanation, and it is a good example of how arbitrary the early gauge decisions were: a unit of measurement in use in one administration in 1846 is still determining, today, what rolling stock can run on twenty-one kilometres of preserved railway.
The practical effect was isolation. Poland has narrow-gauge lines at 600, 750, 785 and 1000 mm, and 785 is effectively confined to this network. Stock could never be brought in from elsewhere when a locomotive failed, and it still cannot.
That isolation is also why the preserved line has the collection it has. Nothing could be sold on to another operator, so a good deal of it simply stayed.