In message , at 11:49:00
on Thu, 3 Dec 2015, David Cantrell remarked:

There's also the length (ie, rise) of the escalator to consider. If it's
very high, fewer people will choose to walk up, so the walking lane will be
under-used, with long gaps. In such cases, having two standing lanes will
maximise throughput. But with short escalators, lots of people will prefer
to walk, so it's better to have a walking lane.
I think this was the reason given for trying it first at Holborn as it
has rather long escalators, but surely not the longest (Angel?).

I've only used Angel station a couple of times but I don't remember it
being particularly busy, so maybe they didn't try it there because
there's no problem to solve there.

Angel station is very busy in the rush hours, but it isn't an all-day
tourist/shopping destination.

Holborn is busy for much longer, and has a congestion problem that needs
solving.
--
Roland Perry