This piece is part of the Sidewalk Talk series "15 Innovations That Shaped the Modern City."
Modern office towers and apartment buildings wouldn't exist without mechanical lifts needed to get people higher than a typical four-or-five-floor walkup. While steel construction accelerated high-rise development in big cities, elevators proved to be a primary engine of urban density over the last century, boosting economies of scale for big cities and redefining urban life. Just as cars made it possible for people to spread out horizontally, elevators enabled vertical exploration of a very different kind. "The entire history of skyscrapers contains an homage to the inventors of elevators," wrote architect and historian Francisco Mujica in 1929.
Records of mechanical hoists go at least as far back as Archimedes. The Roman Coliseum used slave-powered lifts to deliver lions and gladiators to the fighting arena. Centuries later, hoists would be crucial to the functioning of the mines and mills of the Industrial Revolution.
Vertical conveyances eventually changed not just city skylines, but social hierarchies. Before elevators, the rich lived on lower levels; the poor trudged up and down stairwells**. **As Andreas Bernard, a German academic and author of the book Lifted, explains: "you had the garret, the attic, the maids' quarters," but when the lift came along, the bohemian digs "gave way to the penthouse, the roof garden, the chief executive suite." The loftier digs not only afforded better views, they also allowed one to escape the stench and din of the city streets.
The modern passenger lift, or "vertical railway," emerged in the 1850s. Its key innovation was a simple but critical safety feature: the catch.
At the Exhibition of the Industry of All Nations, held in New York in 1853, Elisha Graves Otis---the patriarch behind what eventually became industrial giant Otis Elevator---demonstrated the safety catch he had devised to stop an elevator platform from falling. Standing on a platform hoisted on serrated guide rails, Otis had his assistant sever the rope that suspended him. When the rope went slack, a carriage leaf-spring atop the lift would flatten, engaging the teeth of the guide rails to quickly arrest the fall. Otis then declared: "All safe, gentlemen, all safe."
Some historians credit another Otis---Otis Tufts---with inventing the first fall-proof elevator. Tufts's "vertical railway elevator," patented two years before Otis's, was driven by a large, steam-turned iron screw. The cab moved safely up and down the screw, like a nut threading a bolt.
A real estate crunch in Manhattan during the 1870s may have been the biggest catalyst in getting the modern elevator revolution off the ground. As Bernard notes, business owners at the time were so cramped for space that they briefly considered moving the financial district uptown. But it was Henry Hyde---founder of Equitable Life Assurance Society, the largest life insurance company in the U.S. at the time---who believed there was more to consider in elevators than an upgrade for stairs.
As journalist Leon Neyfakh recounted explained in the Boston Globe, Hyde calculated that "by installing a pair of elevators in his headquarters, he could make it the tallest building in the city: seven stories and 130 feet. In so doing, Hyde ushered in a new era." By the early 1900s, electric traction made elevators even faster and more efficient. The skyline changed dramatically over the next few decades, as did the economics of real estate: Floor area ratio---the ratio of the total floor space in a building to the area of land the building occupies---would double in Manhattan between 1910 and 2010.
Perhaps in an attempt to allay safety concerns as well as what was called "elevator sickness," early elevators were often parlor-like in their opulence, outfitted with cushioned chairs and chandeliers. They were hoisted on cables and pulleys and tended to be located in luxury hotels as an amenity that could be advertised alongside steam heat and in-room privies. While elevators solved one problem for business owners like Hyde, for patrons, "the appeal of the first elevators wasn't about speed or efficiency," says Lee Gray, an architectural historian at UNC-Charlotte. "It was about novelty. It was more like, 'Isn't this cool?' "
Early lifts were run by trained employees directed by an "elevator starter" on the ground level. The starter acted as a kind of dispatcher whose job it was to keep the system running efficiently by a system of signal lamps or other means, including loudspeakers and telephones. While the job title still exists in some places, the traditional role of the elevator starter was replaced first by automated, electromechanical systems, and eventually by microprocessors. The first operator-less units, outfitted with control panels, didn't appear until the early 1950s, and it took many years before riders were comfortable riding without a human operator---an example that may be instructive to developers of self-driving vehicles.
Elevators have progressed since then, but in relatively minor ways. The name of the game in high-rises is still the electric traction elevator, counter-weighted and enclosed in a central shaft. More recent innovations include double-decker cars, machine-room-less models in which the motor travels in the hoistway with the elevator car, and the introduction of carbon-fiber hoist "rope" to replace heavier woven-steel cables.
In Rottweil, Germany, engineers from ThyssenKrupp are constructing a 761-foot tower that uses maglev technology to propel elevator cabs and does away with the traditional suspension systems that only work in a single shaft. These next-gen people-haulers can travel in any direction, horizontal or vertical. One cab can take you from the south side of 10th floor to the northwest corner of the 25th---no transferring or walking required.
Next-gen elevator technology is also helping guide some radical new ideas in building design. Oiio Studios' "Big Bend" concept in Manhattan---a skinny U-shaped structure with elevators that can travel along curves and loops---could force developers to consider a building's total length, not just its height, in determining its value and beauty.