[wikfwikf]

Their justification for this change, as I read it back then, (the linked article doesn't get into the details) seemed to me to be completely flawed.

It is true that standers are more closely spaced together than walkers. The number quoted was a stander every 2 steps versus a walker every 3 steps. However standers spend roughly twice as much time on the escalator as walkers do. This means that walkers take up about 50% more space*time on the escalator, which is the constrained resource.

This error was exacerbated by station staff observing queue length as a goal to minimize. Walking on the left leads to a longer, and also faster-moving, queue for the left side of the escalator. People are happy to stand in this queue, because they are trying to optimize for the time they get off the escalator, not the time they get on. But station staff sees reducing this queue as a success. This is wrong - firstly they don't take into account the higher throughput for the left side. Secondly, making things less desirable definitely makes queues for them shorter, but this is not a win.

In short, standing-only can reduce total travel time for congested escalators where few people walk (obviously), but it makes things quite a lot worse for busy escalators which are at capacity for both walking and standing. (Even before you account for the fact that walkers on average care more about their speed than standers.)

[stdbrouw]

I lived in London for a year or two and I rarely saw an escalator "at capacity" for walking. You can do all of the napkin math you want, but ultimately, as the article says:

> The one escalator at Holborn that allowed you to walk up the left side during the trial had a total of 115 passengers per minute, but the standing-only ones knocked that up to 151. This was only the case during peak times though – when you’ve got under 100 people on the escalators, it doesn’t really make much difference. Either way, introducing standing-only escalators meant that they only had to SHUT THE GODDAMN GATES AAAHHH once during the trial, whereas it was happening almost daily before.

[wikfwikf]

I have seen lots of escalators at peak capacity for walking. Perhaps you didn't travel a lot in rush hour. People (for obvious reasons) are much more likely to walk up escalators in the morning rush hour than in the evening.

The escalators at Holborn are somewhat exceptional as was noted in the linked article, and the anecdata provided by station staff is not particularly convincing. If the station was extremely congested in the morning, it is hard to imagine that very few people chose to walk straight onto the left side of an escalator rather than queue at length to stand on the right.

'Shutting the goddamn gates' really only happens at stations like Holborn in the evening when people are trying to get out of the city centre. The up escalators at Holborn are conversely at their most busy in the morning, so this is a confusing claim at best.

As for the accusation of 'napkin math', I was simply responding to the clearly wrong napkin math which was widely cited in favor of this change. This purported to show that even at capacity, a walking left side was wasteful of escalator space. Without this flawed claim the main consideration simply becomes that if the left side is being used a lot for walkers it should be kept for walkers (obvious) and if not, not (also obvious).

[rjmunro]

The trial was at a station with 2 parallel escalators going in the same direction, giving 4 lanes of people. Instead of having 2 standing lanes and 2 walking lanes, they had 3 standing lanes and 1 walking lane. The goal was to reduce queuing for the standing lanes. The walking lanes are usually a lot less busy.

[wikfwikf]

When I travelled through Holborn during this period, they had changed both of the up escalators in the main bank (ticket hall down to Central/Piccadilly fork) to 'standing only'.

[adammarples]

It doesn't really work like that, people are lazy and even at peak times will queue at the right hand side to stand, even when the left hand side is completely empty

[pydry]

I got kind of mad at this decision for precisely the same reason as you.

I'd like them to put up some signage to encourage people to walk up (it's a low friction way to get some exercise) and try again. I reckon they could increase throughput and make a few people slightly healthier this way.