[jdkram]

Transport for London experimented with this, and found higher overall throughput during rush hour with two standing lanes:

https://www.independent.co.uk/news/science/it-is-faster-to-s...

> Standing-only escalators had a "throughput" of up to 151 passengers per minute, while an escalator where commuters were still allowed to walk saw around 115.

Your thought experiment's completely right, but in real world circumstances, once an escalator is above a certain height, people rarely use the walking lane:

> But a 2002 study of escalator capacity on the Underground found that on machines such as those at Holborn, with a vertical height of 24 metres, only 40% would even contemplate it [walking up]. By encouraging their preference, TfL effectively halves the capacity of the escalator in question, and creates significantly more crowding below, slowing everyone down.

(from https://www.theguardian.com/uk-news/2016/jan/16/the-tube-at-... , which has a great graphic showing the two systems)

[wst_]

Transport for London should politely refrain from any statements like that, I believe. They hardly can allow people to enter the platform because there's no space to fit the crowd. There's sea of heads almost every morning in front of most popular stations' gates. Not because they have a gates issue, or any other unusual problem - they are just regulating flow that way. So, I'd kindly ask them start modernizing platforms to allow more throughput in the first place. Then let them experiment and play with statistics, by all means.

[bboreham]

That’s in one place, which is a particular bottleneck. The general rule is that two lanes are better.