Platform doors

[railtechnician]

May 28, 2011 23:08:44 GMT Chris M said:

Yes, PEDs do require all stock serving the platform to have the same door arrangements^[1]. This includes successor stock unless you replace your PEDS at the same time (expensive) and work out how to deal with the transition period (tricky).

[1]Although in theory I suppose you could design PEDs that worked with two stocks only opening the subset of platform doors that matched the train in the platform. This would be very complicated (and thus expensive) to design and so how practical it would be in the real word I don't know. You'd probably also want to have some way of informing passengers which doors will open for the next train, which depending on how tied to routes stock are and how you describe different lines/routes/stocks mightn't be easy for the unfamiliar traveller.

Just another good reason to think carefully about what is required in terms of a single standard design of stock and then everything else should follow!

[djlynch]

May 28, 2011 15:06:27 GMT railtechnician said:

May 28, 2011 13:13:47 GMT Chris M said:

I'd have thought that straight but not level platforms would just require the doors to be of a staggered height, just like fences on a hill.

True enough but I would think the angle of the curve is important in terms of working clearances for moving doors and staggering the heights of the doors as suggested could involve 'steps' in inappropriate places or require special units.

What about PEDs that open vertically on platforms that aren't level? You would have to custom a piece or two on a sloping platform, but I imagine that something could be created that rises up into the space between the top of the frame and the station tunnel roof by using multiple panels. It would probably need a pretty robust system to keep it from knocking anyone trying to sneak through at the last minute on the head, though!

Actually, now that I think about it, this would be useful for curved platforms, too -- you don't need space outside the envelope of the curved door for it to open, so you could just fit a series of straight panels into as close an approximation of the curve as possible. The tricky bit would be the gaps.

[railtechnician]

May 29, 2011 3:43:17 GMT djlynch said:

May 28, 2011 15:06:27 GMT railtechnician said:

True enough but I would think the angle of the curve is important in terms of working clearances for moving doors and staggering the heights of the doors as suggested could involve 'steps' in inappropriate places or require special units.

What about PEDs that open vertically on platforms that aren't level? You would have to custom a piece or two on a sloping platform, but I imagine that something could be created that rises up into the space between the top of the frame and the station tunnel roof by using multiple panels. It would probably need a pretty robust system to keep it from knocking anyone trying to sneak through at the last minute on the head, though!

Actually, now that I think about it, this would be useful for curved platforms, too -- you don't need space outside the envelope of the curved door for it to open, so you could just fit a series of straight panels into as close an approximation of the curve as possible. The tricky bit would be the gaps.

Ah yes vertical opening doors, the complication is where the door goes! Three possibilities (a) folding door of some sort (b) roller shutter (c) slatted door that can retract over the curved ceiling. All would be not so easy to install and not as good as solid doors, more mechanical maintenance headaches and greater chance of failure, possibly an H&S nightmare under failed conditions!

That's a 'No' to vertical doors I think, they would have many more problems than horizontal ones. However, after thinking about vertical doors I can see that horizontal slatted doors could be made to work on platforms which are flat in the vertical plane but curved otherwise.
As for the gaps I'm sure I've seen a solution elsewhere (can't remember where!) for that, a retractable sliding platform to fill the gap and with step free access. Perhaps I saw this idea somewhere to do with making transport disabled friendly, I'm thinking wheelchairs and step free access here.

[Ben]

Gap fillers on the South Ferry loop, NYC?

[Deleted]

Well gap fillers could become feasable with ATO as the stopping accuracy is so much better. You could also have flashing lights where each doorway is to warn passengers of the gap even more.

[Dstock7080]

May 29, 2011 11:11:30 GMT Ben said:

Gap fillers on the South Ferry loop, NYC?

Not visable now with the opening of the new station .

Bastille station on Paris Line1 isn't exactly straight and has has half-height doors fitted:
tinyurl.com/3vntblw
tinyurl.com/3dj62oj

[abe]

The Jubilee platforms at Westminster are on a slight curve. Each panel is flat, but at a very slight angle to its neighbours.

[Deleted]

Sigh - haven't we done this before? Gap fillers still leave the possibility of passengers gettting stuck between the PEDs and the train, when they are withdrawn the passenger then falls down the gap and is potential wheel-fodder.

In addition the train would need a longer dwell time to allow the gap fillers to come out after thr train had stopped and to withdraw before moving off. And if the gap fillers got stuck in the "out" position you've just shut down the line.

Westminster Jubbly does have a slight curve I beleive but Bank Central and Waterloo Bakerloo have mighty curves and it is these that I had in mind

[Deleted]

I'll have to go to Paris, check out Bastille, see how it works. Like I need an excuse....

[Deleted]

If PEDs are really required, the concept of a gap filler combined with out-moving doors would seem possible, if horrendously complicated and rather service slowing...

[Chris M]

Indeed if gap fillers can extend and retract at the same time and speed as PEDs open and close then the time issue is resolved.

The filler getting stuck out problem could be resolved by designing them so they slide off their mount and under the platform lip without either damaging themselves or the train when a force is applied to them by the train departing. Make them out of a non-conducting material and they wont cause electrical problems on the track. A tether to the base of the platform should keep them away from the running rail and stop them getting blown/dragged along. Some type of rubber or rubberised plastic would possibly be the material to use.
This would then leave the gap unfilled until the filler is replaced, but you'd need to fix the mechanism first anyway, so all you need is some indication to passengers (and maintenance teams) that there is not a gap filler at a given doorway.

This wouldn't solve the issue of pax getting stuck between train and PED though. However having the PED at the distal end of the gap filler would (there being no gap between train and PED in which to get stuck). Almost certainly very complicated to engineer though. And not at all compatible with the above solution for a failed gap filler...

Another solution would be to mount the doors not on the actual platform edge, but far enough back that there is room for someone to stand in relative safety between the door and the train. This would reduce the waiting space on the platform though, and I don't know whether it would have any effect on dwell time.

[Deleted]

etr220, Chris M - all quiet feasible, ingenious and probably hideously expensive

There weren’t any plans under PPP to install PEDs anywhere so considering the financial constraints we will be operating under for the foreseeable future it will probably be a decade or so before this is even considered up at 55.

[edwin]

Well if they were going to install them anywhere it'd be on the Victoria line, or the rest of the Jubilee line, both of which have no problems of severe platform curves.

Personally if you're going to install PEDs on the Central it'd probably be a better idea in the long run to completely rebuild Bank station somewhere where there'd be no curves, unfortunately that seems impossible.

[Deleted]

Was on the jubilee today. Pulled into westminster eastbound and the train doors opened but not the PED'S. After about 10 seconds the driver laughing on the p.a said that westminster have had alot of trouble with them and that they will open shortly. Alot of bemused tourists wondering why both doors didnt open!