Platform Doors

[DynamicSpirit]

It just struck me when travelling on the Elizabeth Line last night that it has platform doors - but only on the underground stations, not at the surface stations. The Jubilee line has the same arrangement on its newest bit.

What's the rationale for that? If platform doors are today deemed an essential safety feature, then why only underground? What possible danger do the doors avert that only exists underground and doesn't exist on open-air platforms?

 

[Western Lord]

One reason is that the underground central section of crossrail sees only the one type of train (obviously, the platform doors have to match up with the train doors). The surface sections are general user and could see other types of train calling.

 

[Nottingham59]

One consideration is that once you fit platform doors, you can only ever have a particular type of train use that platform. That's feasible in the EL tunnels, but not on the GWML slow lines or the line out to Shenfield.

And they take up a lot of space. I would be surprised if it were possible to retro-fit them on the existing Jubilee line platforms. And you'd have to close the whole line for years to do it.

 

[Mike395]

For the Jubilee I believe the main rationale was airflow rather than safety (with the latter just being an added bonus) - hence the lack of Platform Edge Doors on the open-air sections.

My guess (and it is only that) is that the Elizabeth Line spec for the central section was similar - it's also worth noting that the two open air stations with EL-exclusive platforms (Custom House and Abbey Wood) have quite wide platforms and the latter also has crowd control on event days filtering the flow of people down to platform level.

 

[Dave W]

Is it not also that the infrastructure we've built with platform doors is recent? (e.g. underground Jubilee stations north of Green Park are not so equipped)

Building into a new project is one thing but I suspect it's a right faff to retrofit them.

 

[DanNCL]

If I recall correctly the primary reason for fitting platform edge doors in tunnels is actually because it helps improve air flow through the tunnels, with improved safety for passengers being an added bonus. The Northern line extension to Battersea opened last year without them, and the underground platforms on HS2 won't have them either.

Building into a new project is one thing but I suspect it's a right faff to retrofit them.

Retrofit is a faff but it can be done - platform edge doors have been retrofitted to all stations on lines 1 and 4 of the Paris Metro in the last decade.

 

[bnc2018]

the underground platforms on HS2 won't have them either

As far as I'm aware, while not completely confirmed, HS2 stations will have platform screen doors. https://learninglegacy.hs2.org.uk/d...ct-for-integrating-safe-by-design-principles/

The platform islands are fully covered to protect customers from adverse weather. Clear, uninterrupted platform zones are provided along the length of the platform islands, with a central zone for circulation and structure. The platform design prioritises the platform zone. The generous width allows for safe movement and gives clear lines of sight along the platform. This in turn, facilitates intuitive wayshowing, effective platform clearance times and evacuation, inclusive of all passengers. Platform screen doors add to the safety of the platform. In addition to protection from falling, the platform edge doors contribute towards the health and welfare of the staff on the platforms, providing a barrier to noise from the trains to create safe working conditions.

You can see them on some of the renders, like this one of Curzon Street, although they do look a bit more like just barriers than full doors.

 

[Bletchleyite]

With a totally uniform fleet, having fences with permanent signage showing coach locations and where to queue will make boarding/alighting much quicker.

 

[edwin_m]

The main benefit is indeed to separate the airflow, which helps with climate control and also smoke control if there is a fire. Having said that, the Jubilee Line ones don't go all the way to the ceiling so the benefits in that respect are limited.

A few places overseas have vertical lifting platform edge doors, which can cope with trains with different door spacings. But these are very rare.

Another issue is that the doors have to be very close to the train to avoid hazards with people getting trapped in between. This means that any non-stopping trains are limited in how fast they can pass by to avoid putting excessive aerodynamic forces on the doors.

 

[Basil Jet]

As far as I'm aware, while not completely confirmed, HS2 stations will have platform screen doors. https://learninglegacy.hs2.org.uk/d...ct-for-integrating-safe-by-design-principles/

You can see them on some of the renders, like this one of Curzon Street, although they do look a bit more like just barriers than full doors.
View attachment 115458

If you look on the rightmost platform, I'm pretty sure that is a stationary fence with stationary gaps.

 

[ijmad]

One reason is that the underground central section of crossrail sees only the one type of train (obviously, the platform doors have to match up with the train doors). The surface sections are general user and could see other types of train calling.

That doesn't explain Custom House.

 

[30907]

That doesn't explain Custom House.

But post #4 possibly does.

 

[themiller]

If you look on the rightmost platform, I'm pretty sure that is a stationary fence with stationary gaps.

It’s an artists impression. If you look at the base of the barrier posts, they appear to be mounted on the platform face. We’ll have to wait and see what is eventually constructed. As an aside, I’ve seen both side wards opening gates and flexible rising curtains in Japan.

 

[Basil Jet]

I’ve seen both side wards opening gates and flexible rising curtains in Japan.

I had heard that they had theirs set sideways.

 

[themiller]

I had heard that they had theirs set sideways.

The rising one that I saw was at a station between Kyoto and Osaka. It was basically a series of horizontal ropes which were raised when a train stopped in the platform and lowered at departure time. These were only in evidence adjacent to fast lines.

 

[ijmad]

Here are some vertical platform doors in France:

 

[boiledbeans2]

Here are some vertical platform doors in France:

They need a "Mind your head!" announcement for that!

 

[plugwash]

I would think if the crowds were bad enough to make open-edge platforms a major safety risk they would also be bad enough to make crushing a major safety risk.

 

[themiller]

I would think if the crowds were bad enough to make open-edge platforms a major safety risk they would also be bad enough to make crushing a major safety risk.

I think that you’re assuming that waiting passengers are going to be unruly on these platforms. The barriers are there as a safety feature to mitigate against injuries from being put off balance by the slipstream of fast moving trains.

 

[Taunton]

The main benefit is indeed to separate the airflow, which helps with climate control and also smoke control if there is a fire. Having said that, the Jubilee Line ones don't go all the way to the ceiling so the benefits in that respect are limited.

The Jubilee doors do assist with airflow, and it was all modelled beforehand. The main issue at tunnel stations is "pistoning", where the train tightly fitting in the tunnel pushes substantial air in front of it, and likewise drags air in behind it on departure. The platform screens prevent the gale effect at p.latform level. It's quite turbulent up above, but that doesn't matter.

Notably the Dubai Metro, possibly some other modern ones, does have screens that go right to the top, and the whole station area is air conditioned. They have roadside bus shelters the same, air conditioned with road edge doors that open synchronised with the bus door.

 

[Basil Jet]

Here are some vertical platform doors in France:

Mind.. the slap!

 

[AzureOtsu]

The PEDs allow for the trains to accelerate a lot quicker whilst minimising airflow