The two vestibule problem

[HSTEd]

Well we have been talking a lot of late about the efficiency of 26m carriages versus 23m ones, largely as a result of having fewer vestibules since a train formed of 10 23m carriages would only need 9 26m vehicles, thus saving you two vestibules which translates to several metres.

However, I have had another thought along these lines. If we are going to have end doored vehicles for intercity service, with teh arrival of fixed formation trains and rather wide inter-carriage gangways (as seen more recently on the Capitalstars), is it still neccesary to have a vestibule and door at each end of every vehicle?

Surely one at each end would be sufficient and a more efficient distribution of space? The space at the end of the carriage adjacent to the vestibule could use this space for a toilet, luggage space or a buffet counter, or even just as additional space.
With fully sealed wide gangways the vestibule space could include the gangway and you thus eliminate the additional pair of doors neccesary, removing the disadvantage of forcing people at that end to move into the next carriage to access the vestibule.

This way a five carriage flat fronted intercity unit (as often indicated for services in the UK where 110mph or slower running is the norm) could get away with only 4 sets of doors, or perhaps six if the driving vehicles were fitted with two instead of just one to enable them to have vestibules at both ends.

Compared to fitting a full ten gangways the savings in space are manifest.

So why not?

 

[Cherry_Picker]

The first thing I think of is emergency evacuation. One door? What happens if the end with the door gets crushed?

 

[RAGNARØKR]

Well we have been talking a lot of late about the efficiency of 26m carriages versus 23m ones, largely as a result of having fewer vestibules since a train formed of 10 23m carriages would only need 9 26m vehicles, thus saving you two vestibules which translates to several metres.

However, I have had another thought along these lines. If we are going to have end doored vehicles for intercity service, with teh arrival of fixed formation trains and rather wide inter-carriage gangways (as seen more recently on the Capitalstars), is it still neccesary to have a vestibule and door at each end of every vehicle?

Surely one at each end would be sufficient and a more efficient distribution of space? The space at the end of the carriage adjacent to the vestibule could use this space for a toilet, luggage space or a buffet counter, or even just as additional space.
With fully sealed wide gangways the vestibule space could include the gangway and you thus eliminate the additional pair of doors neccesary, removing the disadvantage of forcing people at that end to move into the next carriage to access the vestibule.

This way a five carriage flat fronted intercity unit (as often indicated for services in the UK where 110mph or slower running is the norm) could get away with only 4 sets of doors, or perhaps six if the driving vehicles were fitted with two instead of just one to enable them to have vestibules at both ends.

Compared to fitting a full ten gangways the savings in space are manifest.

So why not?

This is the same arrangement as Eurostars and presumably all the TGV-derived types. Seems reasonable in principle and worth looking into but the effect on station dwell times might rule it out.

 

[HSTEd]

The first thing I think of is emergency evacuation. One door? What happens if the end with the door gets crushed?

Any situation I can think of that would crush the end with the door would do such damage to the carriage that evacuating people surviving said incident would become a purely academic concern as they would probably all be dead.


As to emergency evacuations, you could probably make the doors wider than standard single leaf doors and still save room since a vestibule is wider than the associated door.

 

[sprinterguy]

This is the same arrangement as Eurostars and presumably all the TGV-derived types. Seems reasonable in principle and worth looking into but the effect on station dwell times might rule it out.

The TGV and Eurostar carriages are distinctly shorter, at 18.7 metres, than the 23 metre and soon to be 26 metre carriages used on UK Intercity services, so I agree that the increase in station dwell times, doubling the number of people leaving or entering through each door, would surely put paid to the idea of halving the number of doors in a train formation.

 

[HSTEd]

The TGV and Eurostar carriages are distinctly shorter, at 18.7 metres, than the 23 metre and soon to be 26 metre carriages used on UK Intercity services, so I agree that the increase in station dwell times, doubling the number of people leaving or entering through each door, would surely put paid to the idea of halving the number of doors in a train formation.

You could probably introduce wider doors so people can enter and exit more rapidly and still save room overall, vestibules really are enormous.

 

[LexyBoy]

Eurostar/TGV also operate on long-distance non-stop services of the sort that we don't really have here. If we did then it might be a goer, the longer dwell times would be acceptable.

If you're ever in a busy coach A on an HST arriving into Paddington you certainly notice the effects of only having one door (and coach A has perhaps 2 metres worth less seating than other coaches). Widening doors I don't think would help much as you'll still be held behind people collecting luggage or generally being slow.

 

[HSTEd]

If you're ever in a busy coach A on an HST arriving into Paddington you certainly notice the effects of only having one door (and coach A has perhaps 2 metres worth less seating than other coaches). Widening doors I don't think would help much as you'll still be held behind people collecting luggage or generally being slow.

People who are collecting luggage and being generally slow tend to be in the aisle in the saloon rather than doing this in the doorway though.

Remember you would still have access points at each end of the coaches, just that you would have to go through the full width Cl378 style gangway to reach the other door.

We have pairs of doors a couple of metres apart and this just seems wasteful compared to one wider door.