Putting two elevators in one shaft

As high rises replace their elevator up/down buttons with panels that you enter a floor into, which then direct you to a specific elevator, they create the possibility of adding more cars to each shaft, radically increasing the efficiency and throughput of a building's lifts.

Because the software knows how many people are waiting on each floor, and where they want to go, it can split each shaft into multiple, dynamically sized subshafts that can shuttle people around faster than single-car shafts. This is especially useful in hotels and office buildings where riders might be moving from a midtower floor to a rooftop restaurant or another department below or above them (rather than going from the ground to a single floor and then back).

This creates new information security problems. While elevators can use mechanical brakes to prevent software malfunctions (or hacks) from crashing them into the basement or roof, it's possible that bad code could crash cars together within a shaft at high speed, with disastrous results.

In that case, the two cabins make perfect sense. One makes strategically-planned trips between lower floors, while another ferries people from the middle floors to the loftier locations. When there aren’t enough people moving about to justify two elevators, the system parks one car at the top or bottom of the shaft to save energy.

Beyond easing congestion within elevator cars, the technology frees up space. With each shaft moving more people, buildings need fewer shafts. That creates room for more offices, more conference rooms, more luxurious cafes, more swanky ping pong tables.

Sticking Two Elevators in One Shaft Is Totally Safe—And a Great Idea [Aarian Marshall/Wired]

(Image: Thyssenkrupp)