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Comment by petenixey | Hacker News Reader

It's kind of crazy to think that the platform-side doors will increase service capacity by removing the ability for people to commit suicide in front of trains.

The frequency with which there is "a passenger under a train" must have a tangible effect on tube capacity.

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It's not just that - it's the delay whilst people hold the doors, get their bags/umbrellas/coats/legs stuck in them, etc. With the (over)tight scheduling of the timetable, one train being delayed by a minute can cause a knock-on for a considerable time.

I guess (though I don't use the tube, I can't verify) that the platform-side doors help control this kind of behaviour.

(There was a link going round a year or two ago about (IIRC) New York improving service reliability by reducing the flow and introducing slack into the timetable but I can't currently find it. Lots of academic research into this topic though.)

One of the side effects is that it allows people to queue in the right spot (rather than guessing and lining the platform) which helps even out the number of people trying to get in one set of doors. Adding a bit of predictability helps streamline things.

You see this behavior in the Tokyo metro system. Even better the doors are numbered so people will learn which car is closest to the exit they need. This provides a clean stream of passengers heading to the nearest exit.

I guess if you also annotate the platform with "queue here" lanes (I've a vague memory that some Jubilee stations have this?) then you can try and keep the queues from blocking people leaving the train.

There are white squares on certain Hammersmith & City and Circle and line platforms that line up with where the doors stop, people don't seem to know this though.

Platform overcrowding is also an issue, and passengers are often held back in the ticket hall or outside, because of how dangerous it would be to put more people on an open platform.

With platform-side doors, you don't need to stand behind the yellow line.

It isn't just one-unders, but the fact that the train can't safely move off when there are passengers right up against the train.

I remember being blown away by the platform side doors for the shinkansen bullet train in Japan: the incredible precision with which the train doors align with the platform doors.

Where was that? Most shinkansen platforms I've been on were in the open air.

(Also, London has had platform edge doors for a while already - only on half of one line, but still)

Not sure... one of the Tokyo stations I think. It was still an open air platform, but had doors on the edge of the platform around man-height that aligned with the train doors.

Canary Wharf station has platform-side doors but it still closes the entry at ticket hall level every now and then. One advantage for me is the line formed in front of the platform doors which allows me to wait in front of it for the next train and find a free seat every day.

It definitely has a tangible effect. For example the National Rail going east of Liverpool Street runs equidistant to the Central (to zone 4) and District lines, and has more 'person under train' incidents. Whenever such an incident occurs, both those tube lines plus the National Rail line which runs alongside the District are swamped.

The flip side is that it's not enough to prevent suicides on your line - you'll still get unusual peak capacity issues if it happens on a neighbouring line - but at least you can keep your own trains running.

> The frequency with which there is "a passenger under a train" must have a tangible effect on tube capacity.

It does. Think severals a month, more in November, with almost an hour clean-up, usually at peak times.

So when they are under the train they are no longer a 'customer' but a 'passenger'...

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