In November 2018, six people entered an elevator at the former John Hancock Center in Chicago for the ride down from the Signature Room bar on the 95th floor to the lobby, but the long ride got a lot worse when one of the cables snapped and the elevator plunged 84 floors to the 11th floor. Passengers felt themselves falling and thought they were going to die. Amazingly, none of the passengers had to be hospitalized and there were no serious injuries. However, they did have to wait 3 hours to be rescued by firefighters because there were no openings between the floors. So, how was it possible that one of the worst things that can happen to people in an elevator occurred and everyone survived? Action movies often show the hero getting in an elevator after the evil villain has cut the cables — and disaster ensues. Fortunately, elevators in the real world have so many safety features that this kind of stuff usually never happens. Almost all pulley elevators have between 4 and 8 cables. Even if one cable snapped, the remaining cables would hold the elevator car up. In fact, just one cable is usually enough. Let’s say that all the cables did snap. Then the elevator’s braking systems would kick in, grabbing onto the rails running up and down the elevator shaft. If the brakes failed, you would plummet rapidly, but you would not be in a free fall. Friction from the rails along the shaft and pressure from the air underneath the car would slow the car down considerably. Upon impact, the car would stop, but you would keep going, slamming into the floor. Fortunately, two things would cushion the blow. First, the elevator car would compress the air at the bottom of the shaft as it fell — just as a piston compresses air in a bicycle pump— and the air pressure would slow the elevator car down. Second, most cable elevators have a built-in shock absorber at the bottom of the shaft — typically a piston in an oil-filled cylinder. That would cushion the impact as well. With all these features in place, you would have an excellent chance of surviving any elevator mishap.
