[Flick Lives]

Actually, there is an interesting synergy with steel structures and elevators. You need a steel frame to go much above 7 floors, or walls become ridiculously thick to support a concrete or block frame. But there is little point in building much higher unless you have elevators to move people up to those higher floors. Of course the real break thru made by Otis was constructing an elevator with automatic safely features to prevent the dreaded free-fall.

[12Gauge687]

As an architect and builder in the Chicago-area, I am familiar with the Monadnock Building in Chicago, which has both an iron frame and a load-bearing exterior masonry wall (more than six feet at the base).

I worked on an elevator retrofit project in downtown Chicago in the Nineties. There are so many safety features in the system that I felt comfortable sitting on top of each elevator and riding during numerous tests, including sudden stops and stop and go action.

The programming involved in the design of the elevator system is phenomenal. The system can be tweaked to shorten or lengthen stops and recognize other cars in the system and thereby become express cars if a certain number are stopped on a particular floor.

[IronJack]

the real break thru made by Otis was constructing an elevator with automatic safely features to prevent the dreaded free-fall.

Precisely. The elevator itself is little more than a pulley, which had been around for millennia. But a mechanism that would prevent a precipitous fall in the event of a cable failure is what made the modern elevator practical.