Gangway Seal Question

[MG11]

I didn't want to venture off topic in the other Gangway thread, so I am posting here. How do the gangways on coupled units stay sealed? So, there are couplers which keeps the trains joined together but what is there that stops the actually gangway itself from unsealing when the train turns a bend for example. Is it done with magnetic force on the front of the rubber? There is nothing to the naked eye that looks the two pieces of corridor together (stopping passengers falling out as they walk through). I know obviously there is something that keeps the corridors joined together, I am just wondering how it's done?

 

[Domh245]

As i understand it for gangways between units (or individual vehicles where they are uncoupled) the gangway frame has got a friction surface on one side to help maintain side to side location, and they are also pushed forward (and into contact with the other gangway) by some sort of spring mechanism. It's why half of any gangway that's been in use for a while looks like it's been attacked by sandpaper

 

[MG11]

As i understand it for gangways between units (or individual vehicles where they are uncoupled) the gangway frame has got a friction surface on one side to help maintain side to side location, and they are also pushed forward (and into contact with the other gangway) by some sort of spring mechanism. It's why half of any gangway that's been in use for a while looks like it's been attacked by sandpaper

Ahh, so that's how it works! I never thought of springs!

 

[Domh245]

Ahh, so that's how it works! I never thought of springs!

I used to think it was done with magnets!

 

[LowLevel]

Second generation multiple unit and 'Pullman' style corridor connections as used on later LNER and BR carriages are under compression when coupled from a spring or buffer style arrangement. Modern multiple units tend to be a one piece affair that attach to both vehicles rather than being two pieces.

Older 'British Standard' style ones (like old DMUs and other pre nationalisation coaches) use clips and so on.

There's various different types.

 

[Domh245]

Modern multiple units tend to be a one piece affair that attach to both vehicles rather than being two pieces.

At least in terms of intra unit gangways, the inter unit gangways are of the sprung half type.

I would be intererested if anyone can confirm what is used on the 22xs, they look like they have got spring type things on the vehicle ends preusumably for the gangways but you would have thought they'd be of the modern type which is attached to both ends

 

[Bletchleyite]

As i understand it for gangways between units (or individual vehicles where they are uncoupled) the gangway frame has got a friction surface on one side to help maintain side to side location, and they are also pushed forward (and into contact with the other gangway) by some sort of spring mechanism. It's why half of any gangway that's been in use for a while looks like it's been attacked by sandpaper

Cheers, I've long wondered why only half of it gets scruffy.

 

[AM9]

... So, there are couplers which keeps the trains joined together but what is there that stops the actually gangway itself from unsealing when the train turns a bend for example. Is it done with magnetic force on the front of the rubber? There is nothing to the naked eye that looks the two pieces of corridor together (stopping passengers falling out as they walk through). I know obviously there is something that keeps the corridors joined together, I am just wondering how it's done?

The bottom of the gangways on each coach are secured to the 'footplate?' that is over the coupling, That is fixed to the end of each coach's body so in order to allow movement such as on bends, - and more importantly on reverse curves, those mating surfaces slide against each other, (below the actual floor that passengers walk on. The more the overhang from the bogie centres, the more compliance is needed from the coupling and the whole gangway. On articulated trains, (look out for the Stadtlers on GA), there is a moveable floor that is fixed to the bogie/coupling pivot which takes up a rotation angle about halfway between the two adjacent coach bodies, - just like a bendy-bus or tram.

 

[MG11]

The bottom of the gangways on each coach are secured to the 'footplate?' that is over the coupling, That is fixed to the end of each coach's body so in order to allow movement such as on bends, - and more importantly on reverse curves, those mating surfaces slide against each other, (below the actual floor that passengers walk on. The more the overhang from the bogie centres, the more compliance is needed from the coupling and the whole gangway. On articulated trains, (look out for the Stadtlers on GA), there is a moveable floor that is fixed to the bogie/coupling pivot which takes up a rotation angle about halfway between the two adjacent coach bodies, - just like a bendy-bus or tram.

View media item 3068View media item 3068When you say secured to the footplate, do you mean the grooved plastic strip at the bottom of the gangway, the piece circled in the attached picture? Does it lock automatically when the gangways make contact?
The picture is copyright of Doc Brown's Chemistry.

 

[AM9]

View media item 3068View media item 3068When you say secured to the footplate, do you mean the grooved plastic strip at the bottom of the gangway, the piece circled in the attached picture? Does it lock automatically when the gangways make contact?
The picture is copyright of Doc Brown's Chemistry.

Where is the link to the attached picture?

 

[rebmcr]

Modern multiple units tend to be a one piece affair that attach to both vehicles rather than being two pieces.

Those ones can cover the entire coupling assembly as well — is that to keep it clean for easier maintenance, I wonder?

 

[pompeyfan]

For anyone whose not discovered it yet, going over major pointwork between cabs on station throats (I’m thinking Waterloo in a Desiro, but I’d imagine any similar setup would be the same) is really disorienting.

In my experience of Desiros the coupler noses (where the fly doors are) are sprung against each other with a plate covering the unit to the gangway. I wish I had a photo to explain as it would make much more sense.

Secondly, if a unit has just attached to another unit, the springs will be at their maximum travel, so when the train moves again there will always be a minor lurch while the springs adjust their travel to their normal positions. I’d be interested to know if gangway diesels and also electrostars behave the same.

 

[AM9]

... Modern multiple units tend to be a one piece affair that attach to both vehicles rather than being two pieces.

...

That would be within the unit where the coupling is a spring loaded solid bar requiring depot facilities to mate/unmate. Between two multiple units it would have to be gangway equipment on each unit to make the connection.