They use an underground cylinder, are quite common for low level buildings with 2-7 floors,
and have speeds of up to 200 feet/minute (1 meter/second).
Hopeless hydraulic elevators
They were developed in the 1970s, and use a pair of above ground cylinders, which
makes it practical for environmentally or cost sensitive buildings with 2, 3, or
4 floors.
Roped hydraulic elevators
They use both above ground cylinders and a rope system, which combines the versatility of in ground hydraulic with the reliability of hole less hydraulic, even though they can serve up to 8-10 floors.
