If we want to increase escalator capacity, why don’t we just run the things faster?

A busy day on the tube. Image: Getty.

While Londoners may still be recovering from the trauma, many outside the capital probably completely missed Transport for London’s audacious and sacrilegious experiment at Holborn station.

For three weeks, tube passengers stood on both sides of the escalators going up from the platforms to the ticket hall. There were people standing on both the left and the right. Nobody could walk.

I know: it was madness. I understand your anguish.

TfL’s logic was as follows. On long escalators, the vast majority of people won’t want to walk because humanity is an intuitively lazy species. Thus, huge queues build up at the bottom of the escalator as large volumes of people try to squeeze onto the right-hand side, so that they can obediently stand in line as they chug slowly upwards, like a slightly less sedate, slightly less terracotta terracotta army.

The experiment largely failed, because basically people are stubborn and changing the behaviour of large groups is, like, really hard. But anyone who has stood in a soul-crushing human mob at the bottom of an escalator at a tube station in rush hour will understand just how pressing the need is for a way to increase escalator capacity.


There’s an obvious solution – one that’s likely been suggested by amateur masters of logistics all over the world every time they’ve found themselves in such mildly antagonising and incremental-delay-incurring situations: run the things faster.

Theoretically, of course, this is possible. Escalator speeds vary a great deal anyway, even within London – those in shopping centres or department stores tend to run at about 0.5 metres per second, whilst the London Underground standard is 0.75 metres per second.

Looking further afield, city transport networks across the world run their escalators at all sorts of different speeds. New York City’s are horrendously slow, running at about 0.45 metres per second, whilst Prague, Stockholm, Beijing, Shanghai, and Guangzhou settle around the stately 0.6 metres per second mark. Sydney, Singapore, and Seoul’s systems square up sensibly to London’s standard speed in the 0.75 metres per second region, with Seoul pushing ahead slightly at 0.78 metres per second. The trailblazer, though, is Hong Kong, whose escalators breeze along at 0.8 metres per second.

Fantastic! Great! So, all we have to do is compare escalator capacity in Hong Kong MTR stations with capacity in London tube stations, and-

This escalator on the Stockholm metro is not suffering from overcrowding. Image: Getty.

Unfortunately the comparison isn’t that simple. London’s escalator steps are, as standard, 1 metre wide and 0.4 metres deep. Many of Hong Kong’s escalators are significantly narrower and not as deep. Whether that’s clever space-saving on Hong Kong’s part, or ingenious future-proofing for the post-mass-obesity world by Transport for London, we may never know – but either way, it changes the rate at which steps reach the top, rendering direct comparisons based on speed alone impossible.

The speed limit

What we can do instead is to look at a bizarre study carried out by four students from Hong Kong on the relationship between escalator speed in metro systems and “pace of life”. They described that rather dubious metric described as “the rate; speed and relative rapidity or density of experiences, meanings, perceptions, and activities”. They calculated it by combining economic, climate, employment, and population indices.

One of the things they did as part of that study is to conduct reasonably lengthy interviews with users of metro systems (principally the Hong Kong MTR) about their experiences of the escalators on that system, and how that related to their impression of the city’s “pace of life”.  One businesswoman in her mid-twenties interviews for the study said that “Hong Kong people are used to the fast”; but most of the non-locals that they spoke to, mostly from mainland China, said that the escalators on the Hong Kong MTR were “too fast”.

Such comments highlight one of the biggest problems with running escalators faster. A study by Paul Davis and Goutam Dutta has already shown that the presence of non-commuters decreases capacity on London’s escalators. Meanwhile, an experiment with variable speed escalators in New York ended up with a Indian visitor falling over.

There is quite obviously a safety danger to be taken into account if you’re going to start running escalators at 0.8 metres per second or faster. The queues at the bottom of Holborn’s escalators might be shorter most of the time if said escalators are whizzing passengers upwards at silly speeds – but they’ll likely be considerably longer while the paramedics try and reach the elderly man who’s tumbled fifteen metres down an up escalator. Swings and roundabouts, you know?

For those less interested in actual human health and welfare, and more interested in the technical side of running large transport networks, there’s another problem with running such escalators at speed. The average walking speed is around 1.3 metres per second. If you take the running speed of London Underground escalators – 0.75 metres per second – and the rate at which people generally ascend the steps if they’re walking – around 0.7 metres per second – you end with a speed of 1.45 metres per second.

So people walking up escalators are actually travelling slightly faster than they do the rest of the time. And that’s a problem. When it’s only an incremental difference (0.15 metres per second), it leads to nothing more dangerous that awkward mincy super-walk that people do for the first few seconds after walking off the end of an escalator.

But when there’s a bigger difference in speed, it can cause major problems. Either, people trip over their own feet trying how to remember how to walk on non-moving ground, and cause a capacity-reducing pile-up in the process; or people stop at the top of the escalator to prepare themselves for walking on non-moving ground. And cause a capacity-reducing pile-up in the process.

Neither does this one in Lisbon. Pretty, though. Image: Getty.

Essentially, speeding up escalators causes more problems than it solves, and is ultimately no more than the silly solution of the kind of person who still hasn’t grown out of the childish habit of following every piece of information with, “But why?”

Start again

Fortunately, researchers Davis and Dutta do come up with some more sensible alternatives. Unfortunately, these are the sort of drastic changes that are much easier to implement you haven’t built your metro system yet than they are if you’re trying to unclog a jam-packed 150-year old system.

Of the many London Underground escalators they studied, the researchers found that those with the highest peak-time capacity were escalators with open, orderly approaches, not impeded by awkward corners and cross-flow confusions.

They found that having a corridor between the platform and the escalators acts as a filter for passengers alighting a train, improving capacity as passengers naturally filter out into two lines – one for walking and one for standing – in an orderly way (rather than the human crush you get when you come straight off the platform, turn a corner, and suddenly there’s an escalator). Interestingly, single escalators have a higher capacity than double escalators, because passengers don’t dither trying to work out which escalator to take.

So. If you want to get more of your passengers onto your struggling escalators during peak hours, you basically need to redesign your entire underground station. You need to build stations that naturally filter your passengers out into fast walkers, slow walkers, escalator standers and escalator walkers, and divide them into distinct groups.

Most of all, you need to not break any codes of etiquette that are probably as old as the city itself.

Jack May tweets as @JackO_May

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