That stopped escalator? It's a tougher climb

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That stopped escalator? It's a tougher climb

The Globe and Mail

Philip Jackman

March 25, 2011

This week, Collected Wisdom is definitely going up in the world. But only one step at a time.


“When an escalator is not functioning but people can still walk on it, everyone seems to avoid it and take the adjacent stairs,” writes Eric Morris of Montreal. He wonders why. An escalator that has stopped and a set of stairs are basically the same thing, he says.


Not quite, says Derek Wilson , a retired engineer of Port Moody, B.C. “A typical stairway will have a tread depth of about 11 inches [28 centimetres] and a riser height of about seven inches [18 cm],” he writes. These dimensions make for a “comfortable” stairway to ascend, he says. The stairway's angle of inclination from the horizontal is about 32 to 35 degrees.

Now, as George Fowler of Halifax points out, an escalator, in contrast, “is designed as a series of platforms upon which people can stand and feel comfortable,” so the tread is long relative to the rise. Yes indeed, Mr. Wilson says, that's why an escalator has a tread depth of about 16 inches (40 cm).

For an escalator to parallel an adjacent stairway, which often has intermediate landings, Mr. Wilson explains that the escalator must have an angle of about 27 degrees or more. “The geometry, then, requires that the escalator have a greater riser height of eight inches [20 cm] or more.”

So, the greater riser height and tread depth of a stalled escalator make walking up it more difficult.

Mark Cole of London, Ont., adds that it's also partly in our minds. We're used to escalators that move, he says, and “have learned to adjust our pace as we plant our leading foot on what is, in essence, a belt moving away from us.”

Mr. Cole says it is difficult to suppress this learned response when we step onto a stationary escalator, giving us an uneasy feeling.

For the final thought on this, though, back to Mr. Fowler, whose wife never uses a stopped escalator because, she says: “You never know when the darned thing is going to start up.”