Elevator: the Vertical Railway

Before 1853 the top floor of a building was the cheapest floor in it. Servants and clerks climbed; the principal took the first floor. Height was a penalty measured in stairs.

The demonstration

Elisha Otis was a mechanic who had built a hoist to lift heavy machinery in a Yonkers bedstead factory. At the 1853–54 Exhibition of the Industry of All Nations in New York he stood on a platform, had the rope cut with an axe, and did not fall. A wagon spring, held flat by the tension of the rope, snapped outward when the rope went slack and caught teeth in the guide rails. He said: All safe, gentlemen. The first passenger safety elevator was installed in the Haughwout Building on Broadway in 1857.

What changed

The penthouse. Once the top floor could be reached without effort it became the floor with the view, the quiet and the rent. The elevator inverted the price gradient inside the building, and by inverting it, made the building worth stacking.

The machine

A car and a counterweight hang on ropes over a traction sheave driven by a motor; the counterweight balances the car plus about forty percent of its load, so the motor moves only the difference. Hydraulic elevators push the car up on a ram for low-rise. Machine-room-less designs put the motor in the hoistway. The controller — the brain — decides which call to answer first, and modern destination-dispatch systems group passengers by floor before they board. Safety gear, governor, buffers, door interlocks, and the firefighter's key are all in the code.

The code

ASME A17.1 / CSA B44, the Safety Code for Elevators and Escalators, and a state or municipal inspection every year. The elevator is the most regulated machine most people ride.

The trade

Elevator mechanics are among the best-paid construction workers — $70,000 to $135,000 — and almost all of them come through the union apprenticeship (NEIEP/IUEC), four years of paid work and study. VoTechWorks runs the pre-apprentice program that gets a student to the door: hydraulics, traction, controls, the code, safety.

The math of the core

A tower's core is sized by its elevators. Too few and tenants wait and leave; too many and the rentable floor area disappears into shafts. Sky lobbies, double-deck cars and express zones are all answers to the same equation. The vertical railway is the building's circulation, and the engineer who sizes it decides how tall the building can profitably be.