After serious thinking newshound wrote :
You really have to admire the ingenuity of people who managed to make these
work so well! It's (sort of) a logical successor to Brunel's atmospheric
railway.

+1

A very complex system to develop. I wonder why they developed it as a
below ground drive system, rather than on poles like a ski-lift?

Interesting stuff.

Its not that long ago that I heard about the extensive hydro power
(pressurised water) distribution systems they had in some large cities.