Friday, 6 May 2016

"Holborn Tube station to trial 'standing only' escalators for six months"

From The Evening Standard:

Tube commuters will be told to stand on both sides of the escalator at a busy central London station for six months - in a new trial which could pave the way for a permanent change.

Passengers are again being asked to ignore the decades-old "walk on the left" rule at Holborn in a bid to cut queues and ease congestion.

A three-week test run at the station late last year showed 30 per cent more passengers could travel on the escalator if they stood on both sides, Transport for London said.

This is one of those lovely counter-intuitive solutions, it took me a while to suss it out.

The point being, if an escalator is very long, then very few people will want to walk/run up the left hand side and most will wait/jostle in the queue on the 'standing only' side.

Imagine the escalator were so long that nobody can be bothered to walk/run up it and everybody waits/jostles for a place on the 'standing only' side... in that case, making it standing only on both sides doubles the capacity and greatly reduces the time spent waiting at the bottom.

Conversely, if an escalator were very short, most people would be happy to walk up it, so making it a 'no standing at all' escalator would also speed things up.


Graeme said...

It's also a societal thing. I have never once seen a Dutch person walk up or down an escalator, and they invariably stand still on horizontal travelators as well. It's as if, this is a free gift and I want as much of it as possible.

Dinero said...

I suspect most people overestimate the time they are saving as a proportion of the journey time by walking up. For example if you travel 20% faster you do not get to the destination in 20% less time.

It may seem counter intuitive, but consider, if you travel 100% faster you certainly dont get to the destination in 100% less time , the 100% increase in speed only reduces the journey time by 50%, and so on.

paul said...

Considering I tripped and fell on the way up the escalator this morning, I think I'll try standing a bit. I usually travel in the last coach of the train so I can be first on the escalator and leisurely walk up the standing side while holding onto the right hand side, today I tripped in front of everyone.

Steven_L said...

Getting rid of the 'fast lane' is just pandering to the elderly and the lazy. It's real lowest common denominator stuff and not something the 'young' people's party should in any way support!

Curtis said...

This slows down the people who usually walk up quickly, but on average everyone gets up faster.

But they are only going to make half of the escalators standing only and some will still be free for walking.

Mark Wadsworth said...

G, interesting. I love walking along moving walkways.

Din, true. On an escalator, you only save a few seconds, it's the principle really not the actual time saved.

Paul, cause of trip?

SL, true, but there are fat, lazy and disabled young people too.

C, true and true, I ignored that second bit.

Ralph Musgrave said...

No, no, no: COMPULSORY walking would keep people fit and more than pay for itself via reduced costs for the NHS.

Lola said...

It's the same principle as variable speed limits and discouraging of lane changing on the M25. More traffic flows through a given section of road at times of peak flow. The trick is getting the actuall regulated speed 'right'.

Mark Wadsworth said...

RM, that sounds like health fascism to me. What you mean is "turn off the escalators completely and make everybody walk", if you are going to do that then why not "shut down public transport and ban cars and bicycles"?

L, exacfly. Apart from the fact that driving at a constant speed is more pleasant and uses less fuel,, wear and tear than speeding up and braking all the time.

paul said...

Tripped because I was tired, also disability related hence why I wall up the standing side. Probably completely unsafe but I get so impatient when I am late.

I think I gain a minute by walking up and can just avoid a late clock in but could be my imagination.

paulc156 said...

Would have thought that standing only on long escalators would just transfer the bottleneck to the barriers at the top.

Shiney said...

Theory of Constraints - Goldratt addresses all this - so you just need to read "The Goal" and all his stuff. In a production environment you need to balance flow through the system to achieve maximum throughput (sales) while minimising investment and inventory (WIP).

In short - a system can only produce at the speed of the slowest operation. So speeding up one part just causes the work in progress inventory (in this case passengers) to pile up in front of the the next bottleneck.

@Paul156 - people walking faster up the escalators will just pile up at the exit gate if they can't be processed - so balance the flow through the system and increase it through the bottleneck.

See.... easy! (Only joking).

Ben Jamin' said...

So, a case where supply cannot meet demand?

Banning walking is the Statist solution, and sub-optimal.

Perhaps a small additional charge on those wishing to stand would sort it out? 50p extra should get more people choosing to walk?

Internalise those costs I say.

Mark Wadsworth said...

PC, Sh, yes, it might just shift the bottleneck elsewhere, that's no reason for not trying it. It is an 'experiment'.

BJ, they are not banning anything - they are allowing people to stand on both sides, you can still try walking up if you wish.

Shiney said...


Oh yes... agreed. Goldratt would say.... 'elevate' (really!) the bottleneck. Which just shifts it to somewhere else.

So then fix that one, and so on.

Ultimately the only 'constraint' is the 'market' for the throughput you can produce.

If you haven't read The Goal, and related works, I strongly suggest them.

Bayard said...


Goldratt's theory is obvious to anyone who has tried to drive out of London on a Friday evening. It always surprised me that highway engineers didn't seem aware of it. (Although I was told that highway engineers don't like running lots of little projects to optimise a road's capacity, they prefer building new ones.)

Ben Jamin' said...


Quite right. In fact it's the other way around.

1. Original way of delineating which side to walk is the Statist solution. The worst.

2. The new way is a Free-for-All, a Faux-Lib solution. Better.

3. Charging people to pay rent for a scarce resource, ie a 50p standing surcharge, the Geoist solution is best.

In theory at least. But hey who knows? One day when we all have NFC chips implanted option 3 might be practical.

Dinero said...

For lowest elapse time a steady speed is best as traveling faster over part of the distance does not compensate for traveling proportionally slower over the rest.

Similarly, Allocating the same number of people to each stage in a multiple stage project is best , as having more people on one stage does not compensate for having less people on another.

And adding a person to a later stage of a project in response to a person being absent from a previous stage does not result in completing the project in the original elapsed time for project.

mombers said...

Another way of looking at this is that it is actually an optimal solution as there are options for more people. The people who stand are not in enough of a hurry to walk or would prefer to read a book, etc. A small proportion are unable to of course. The people who want to get where they are going to quickly or (like me) need to get some exercise, do so. I've been behind slow walkers many a time and bear them no grudge. Except if they don't walk on the right when it is well clear :-)

Dinero said...

I call it the "denominator effect" , changing the size of the denominator of a fraction does not change the size of the fraction by the same amount.