On Sun, 29 Nov 2015 14:34:18 -0000, "Robin" wrote:

Basil Jet wrote:
That's what people are implying when they say that the capacity of an
escalator is reduced by walking.

Well it all depends on (among other things) how many people walk, at
what speed, and when they arrive.

In any event given where we are starting from I'd put the proposition as
"the capacity of the escalators is reduced by the current practice of
leaving the left side empty for walkers". Whether or not that is true
depends both the number of people who walk up and on the speed at which
they do so. And also on the current incidence of people who block the
left side - eg from ignorance; by being morbidly obese; with luggage;
with large buggies; with young children.

IIRC it is a problem of a class which cannot be solved analytically but
can be modelled since computers have had sufficient grunt to process
large volumes of data.

The issue seems to be simply that walkers leave a longer gap between
themselves than standers do. If people walk at different speeds, then
gaps open up, even if they were equally close at the beginning, and
the rest of the walkers behind the slow one also have to slow down.

Also, with longer lifts, fewer people feel like walking, so the
walking side gets under-used. That's why having both sides standing is
most likely to leave to a net increase in capacity with long upwards
escalators.