Door open buttons when alighting

[radamfi]

I have noticed that older trains allow the door open button to be held down before the train stops and the door opens as soon as the guard/driver releases them.

However, on the more modern trains, you have to wait until the door is released before pressing the button. If you hold down the button before the train is released, the door won't open.

Is that deliberate?

 

[cjp]

Not being one to lean on buttons I have never noticed.
Must play later today

 

[quarella]

Thereby leading to more claims that the doors failed to open.

It's called progress.

 

[maniacmartin]

We discussed this before. Read all about it from post #78 onwards on this page.

 

[radamfi]

We discussed this before. Read all about it from post #78 onwards on this page.

Oh right, so it can't be a safety feature as Desiros don't have this 'problem'.

 

[Cherry_Picker]

Thereby leading to more claims that the doors failed to open.

It's called progress.

Or fewer people falling over if they are leaning against the door while somebody else is leaning on the button.

 

[jon0844]

It is odd that if you are holding the button and it lights (on say a 378), it won't open and needs you to press again.

I don't see it as a safety feature (I mean, someone can press it at any time and if the door was somehow faulty, surely it would open anyway) but another quirk.

On a busy service where everyone is in a rush (again, say a 378) you have a second or two where people must wait for the light as if playing a game of whack-a-mole, rather than just hold the button!

 

[gunn13]

I've found the difference to be between if it is a diesel or electric set.
On the 156, 158 and 170 sets I've been on; they all require the button to be pressed after it is illuminated. Whereas on the 318, 320, 334 and 380 sets it works with holding the button down before it lights. I can only speak for ScotRail trains though.

 

[rebmcr]

On Metrolink's M5000s, you can press the Door Open button whilst they're locked, the button will start flashing and continue until they're unlocked and open automatically.

This even works if a late passenger tries to open them from outside just before departure — they'll open at the next station with nobody present.

 

[northwichcat]

On a Pacer it opens when you hold the button down before the doors are released. However, with Pacers the illumination of the internal door controls is very poor plus the controls are well hidden.

 

[michael769]

I've found the difference to be between if it is a diesel or electric set.
On the 156, 158 and 170 sets I've been on; they all require the button to be pressed after it is illuminated. Whereas on the 318, 320, 334 and 380 sets it works with holding the button down before it lights. I can only speak for ScotRail trains though.

Scotrail 156 doors definitely open when you are holding the button down - I do it quite regularly.

 

[gunn13]

How strange; never seemed to work for me.
I'm not often on a 156 however. The 158 and 170 definitely do not work the same though.

 

[Lockwood]

I'm used to seeing this pattern:
Train pulls into station.
Person presses button.
Nothing
Person mashes button.
Guard releases doors. *PING! PING! PING!*
Mashing continues.
Doors open.
Mashing continues a little longer.
People try to alight, their exit blocked by people stood in front of the now open door, unmoving.

 

[jon0844]

In Stockholm, the (Alstom X60) commuter trains now require users to open the doors (previously they auto opened like tube trains). Of course this now confuses a lot of people, such that they have stickers all over the place and even pictures of people pressing the button on the outside. There are also messages in English on the departure screens.

But the bigger problem is that the buttons themselves are really spongey and hard to press and the green LED lights really dim (or faded).

They also put the button in the middle on the outside which forces people to be blocking the doorway for people getting off.

What I didn't check was if you could press them early.

 

[bronzeonion]

I've got an idea! Why not just have all doors open and close without passengers having to play whack a mole with buttons on routes such as London Overground and other busy commuter routes. The tube seem to have no problems

 

[michael769]

I've got an idea! Why not just have all doors open and close without passengers having to play whack a mole with buttons on routes such as London Overground and other busy commuter routes. The tube seem to have no problems

Because people sometimes lean against the doors and then fall out when they open. Tube trans (mostly) have a much narrower gap between train and platform, than do NR trains where the risk of ending up between train and platform is unacceptably high.

 

[causton]

I've got an idea! Why not just have all doors open and close without passengers having to play whack a mole with buttons on routes such as London Overground and other busy commuter routes. The tube seem to have no problems

And when people fall out of doors, get rained on and wind going through the carriage in the colder months and get blasted with hot air from outside (and if the train has air con break it?) in the summer months...

 

[PermitToTravel]

I don't think that has anything to do with it - there are parts of the underground with room for plural people to fall into the gap:

There are certainly routes where guard (or driver) operated doors would make a noticeable difference to dwell times, including pretty much every London inner-suburban route
--- old post above --- --- new post below ---

And when people fall out of doors, get rained on and wind going through the carriage in the colder months and get blasted with hot air from outside (and if the train has air con break it?) in the summer months...

Weather problems can be easily alleviated with a combination of a passenger-operated door close control, and automatic closing after $N seconds, as used on the LU S stock

 

[rebmcr]

I don't think that has anything to do with it - there are parts of the underground with room for plural people to fall into the gap:

There are certainly routes where guard (or driver) operated doors would make a noticeable difference to dwell times, including pretty much every London inner-suburban route

Nobody wants to be on paper as making the decision to switch, only to get hauled in front of the courts if some wally gets themselves killed.

Weather problems can be easily alleviated with a combination of a passenger-operated door close control, and automatic closing after $N seconds, as used on the LU S stock

Having to keep getting up to close the door is a terrible idea.

 

[PermitToTravel]

Nobody wants to be on paper as making the decision to switch, only to get hauled in front of the courts if some wally gets themselves killed.

A death, as opposed to a sore bottom, is extremely unlikely - if you are leaning on an opening door, you are not likely to remain upright enough to fit in a gap, and in the rare event that you are, a train will not move off with you still in that gap.

An exception to this is in the case of a wrong side door opening, presently more common on NR than on LU, where there is an automatic system to prevent this. Many modern trains also have automatic SDO systems, and these could be made a requisite for having guard/driver operated doors.

Having to keep getting up to close the door is a terrible idea.

Hence the timeout before the doors automatically close themselves.

 

[dcsprior]

I think the ideal would be:

• If the button is pressed when illuminated, the door opens
• If the button is pressed when the train moving faster than 5mph, it is ignored
• If the button is pressed when not illuminated but that if the button was pressed when not illuminated but the train was stationery or moving slowly then it sets a flag
• If the train moves faster than 5mph, this flag is cleared
• If the train moves at all for more than 10 seconds, this flag is cleared
• If the flag is still set when the door-open light comes on, the door opens

 

[jon0844]

The doors should not open until the doors are unlocked, by the driver or guard. Thus there's no problem holding the button for the whole journey if you're so inclined.

I don't know why we now have a system that, when the door button is activated, can't detect it is already being pressed. Or that it can but has been told to ignore the input.

The system behind it is what is safety critical, not the button itself.

 

[kieron]

[*]If the flag is still set when the door-open light comes on, the door opens

That sounds good. It'd certainly beat standing on the platform, listening to a train beeping like crazy, and waiting for the button on the door in front of you to light up. And then, when it does light up, try to press it as quickly as possible, grab your stuff and board within a couple of seconds if you don't want to hold the people behind you up.

 

[jon0844]

I am at a loss to work out any safety benefit of not allowing the button to be pressed before it lights.

Perhaps someone thought a passenger might be leaning on the button and accidentally open the door? I guess the new set up might prevent that, assuming the person doesn't move and re-press it anyway!

 

[tony_mac]

I'm pretty sure the Vienna metro works like that - you press the button when coming into the station and the colour of the button changes (so you don't end up mashing the button!). Then, when the train stops, the door opens.

 

[TOCDriver]

Well, I'm a 'finger on the button before guard release' operative. When I'm coming back from Preston on a 390 I do this, and the door will always open on the TM's release

 

[westcoaster]

I am at a loss to work out any safety benefit of not allowing the button to be pressed before it lights.

Perhaps someone thought a passenger might be leaning on the button and accidentally open the door? I guess the new set up might prevent that, assuming the person doesn't move and re-press it anyway!

I don't think it's a safety benefit bit just how the buttons are wired up, for example on a 377 you have to wait for the button to light up before pressing it, I think it's just a simple case of breaking the circuit before its energised.

 

[edwin_m]

I am at a loss to work out any safety benefit of not allowing the button to be pressed before it lights.

Perhaps someone thought a passenger might be leaning on the button and accidentally open the door? I guess the new set up might prevent that, assuming the person doesn't move and re-press it anyway!

That is a possibility, as is a fault on the button that makes it effectively behave as if it was pressed the whole time.

The anti-preselection* function may be to create a furrher line of defence against the hazard of people falling from open doors when not at a platform. This can only arise if the doors are released at the wrong time or on the wrong side, or some wrong-side failure of the vital circuitry makes it behave as if this has happened.

The anti-preselection function means that if this happens someone would have to actively press the button for the door to open. Nobody is likely to press the button when the door in question is not next to a platform, particularly if there are other people leaning on the door who might fall out if it opened. Without anti-preselection, an incorrect release coinciding with someone leaning on the door or with a button fault would open the door - and if the train is full enough for people to be leaning on the button then there may be a greater risk of someone falling out if the door opens unexpectedly.

So anti-preselection reduces the likelihood of the dangerous event (door opening and person falling out). All this can be sort of quantified to see if the change in risk is worth worrying about, and potentially either somebody has either done this in the rolling stock safety case or decided that it is an increase in safety at zero cost so it should go in anyway (inconvenience doesn't count in a safety case!).

*Not sure if rolling stock people use it but preselection is the signalling term for the same thing. Signalling panels include anti-preselection features so that you can't just hold down a route button for the route to set as soon as a conflicting route has been released.

 

[jon0844]

If this is a new safety recommendation, I wonder if the test 321 with GA will work like that? Or indeed if the 319s will when they get upgraded? Or even the 365s.

In fact, do the Southern 313s now work like this?

 

[dosxuk]

I think it just comes down to different programming practices.

There are two basic ways of detecting an input with a processor - either continually poll the input looking for changes and then act on them, or have the hardware raise an interrupt in your code when the input level changes. Using the former you can add the state of that input to other logic (e.g. "is the door unlocked?"), the latter you can't, but it's simpler to program.

I doubt the perceived safety benefits are enough to write a new standard for, but they're probably sufficient to dissuade Bombardier from changing their design.