Just for the heck of it, the elevators with the greatest potential for a catastrophic downward fall are older hydraulic elevators installed prior to about 1973.
As mentioned above, traction (roped) elevators are equipped with a multitude of brakes, governors and sensors for safety. These elevators run in tall buildings at speeds of 500 to 2000(!) feet per minute, depending on the installation, typically around 750 fpm +.
Hydraulics are in smaller buildings, run at lower speeds of 75 - 225 fpm and are (in most states) equiped with no brakes, governors or safeties.
The logic is that if a catastrophic break occurs in the oil line or piston the oil can only exit the system at the max rate of the size of the oil line (usually about 4" dia). This would allow the elevator to descend at a speed substantially faster than “contract” speed, but not so fast as to cause more than minor injuries when it hits the buffer spring located at the bottom of the guide rails.
However, older hydros possess an Achilles heel in the form of “single bottom jacks”. The hydraulic cylinder in mid to tall hydraulic elevators hangs in a hole below the bottom of the elevator shaft. In the old days these holes were not sealed, the jack (hydraulic piston) itself was not sealed and had a single layer bottom.
After years of environmental and electrically induced corrosion in a dank hole the single bottom can corrode, and then fail and allow the hydraulic oil to rush out at a rapid pace which causes the elevator to reach dangerous downward speeds.
Serious catastrophic injuries, including deaths have resulted because of these accidents.
Modern elevators use a double bottomed jack, a cased hole and a piston sealed in PVC to prevent environmental leakage, so this is no longer a concern.
Most single bottom jacks have been replaced and modernized, but cost and difficulty is considerable, so some building owners continue to operate them as they are.
Reputable elevator companies will not provide service contracts to these buildings. Unfortunately, in my state it is impossible for the State Elevator Inspector to shut them down because they met code at the time of installation.
So if you find yourself in a building that was built around the late sixties, riding in a creaky old hydraulic elevator, you’ll have a little something to contemplate as you go past the fifth floor…