Mount a large horizontal beam, with a
motorized pivot, atop every large
building
in a city centre. The radius of each beam
will obviously be limited by the distance
to
the nearest taller building (if not by
gravity).
A system of pulleys allows a large
elevator-style passenger car
to be
lowered
to ground level from either end of the
beam (and, obviously, to be lifted again).
With a bit of clever design, the cars at
opposite ends of the beam will largely
counterbalance one another - as one car
goes up, the one at the other end of the
beam goes down.
Passengers can be picked up at a number
of stations spaced around the perimeter
traced out by the beam on the ground
and, after a short but exciting ride (up;
round; down) deposited safely and swiftly
at any other point on the same
perimeter.
If all large buildings are suitably
equipped,
passengers can swap cars at points
where
the tangents of two cranulators almost
touch.
Note that there is nothing to stop a
small-radius cranulator operating
entirely inside a larger-radius cranulator,
provided obviously the inner cranulator is
mounted on the shorter building. Wheels
within wheels.
With a little bit of integrated control and
good insurance, it might even be
possible
for the cranulators of adjacent buildings
to
"mesh" with one another, and to actually
pass cars from one system to the next,
allowing passengers to move across town
without even needing to descend in order
to change cars.