A Question of Bus Doors

[LUYMun]

Recently I’ve come across a Flickr image of a Nottingham City Transport Optare Solo, which has piqued my interest on its front doors: rather than the standard design that allows each individual door to open parallel to each other, these fold inwards much like older buses that came before it. They also seem prevalent in NCT's batches of Solos from V to 51 reg as well as some of NCT’s other fleet (such as this Lolyne).

Forgive me for not explaining it in the correct technical matter, but from what I can see in the evolution of bus doors, many older buses have a double-fold style which would fold inward as they open (see this Leyland National as an example). Sometimes this would be a single-fold (Leyland Olympian) which allows it to move to one side and have a handle present to aid passengers.

So this prompt me to ask: why did manufacturers switch to the standard design described in the first paragraph on most buses – is there any technical advantage over the older style doors? Also is it possible for an operator to make amendments to have inward-folding doors as seen on the NCT Solos?

 

[mjc]

Recently I’ve come across a Flickr image of a Nottingham City Transport Optare Solo, which has piqued my interest on its front doors: rather than the standard design that allows each individual door to open parallel to each other, these fold inwards much like older buses that came before it. They also seem prevalent in NCT's batches of Solos from V to 51 reg as well as some of NCT’s other fleet (such as this Lolyne).

Forgive me for not explaining it in the correct technical matter, but from what I can see in the evolution of bus doors, many older buses have a double-fold style which would fold inward as they open (see this Leyland National as an example). Sometimes this would be a single-fold (Leyland Olympian) which allows it to move to one side and have a handle present to aid passengers.

So this prompt me to ask: why did manufacturers switch to the standard design described in the first paragraph on most buses – is there any technical advantage over the older style doors? Also is it possible for an operator to make amendments to have inward-folding doors as seen on the NCT Solos?

The doors in the first images you’ve shared look pretty standard to me; I’m not sure what you mean by what you refer to as the standard design. It may be helpful if you could share an image of those for comparison…

 

[skyhigh]

The doors in the first images you’ve shared look pretty standard to me; I’m not sure what you mean by what you refer to as the standard design. It may be helpful if you could share an image of those for comparison…

Yeah, it looks like a normal set of bus doors to me so no idea how it differs to 'the standard design'.

 

[ACBest]

Just for context, the doors in the photos above are of a concertina design, rather than the more normal double-leaf.

 

[K4016td]

Zoom in the picture that OP had mentioned, you can see set of door hinges in the middle of the door rather than the usual rubber ''insulation'' Maybe that way they can use a single pneumatic piston rather than two in synchro?

 

[SSmith2009]

the doors on some of the early NCT low floors opened to one side like a concertina type.

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Maybe that way they can use a single pneumatic piston rather than two in synchro?

I believe they did which was quite loud on a few examples

 

[MCR247]

So I don’t think NCT modified their Solos or Tridents to have the inward folding doors, I think it was just how they specified them when ordering. Off the top of my head their first Trident/Lolyne T405 something something something had the standard door as well as bonded windows instead of glazed.

I also recall their S reg optare solos having the normal opening doors, so it was clearly a concious choice

 

[py_megapixel]

I think the common modern type of door is described, in at least one specification document anyway, as an "inward glider" door. The doors pivot and slide so that the face of the door that is on the inside when closed faces into the doorway when open.

A disadvantage of some other designs is that when the door is opening or closing it sweeps through quite a bit of space inside the vehicle meaning that space can't be used for standing passengers. On older vehicles, where nobody was going to stand near the doors anyway because they were down some steps from the saloon, this didn't really matter, but it wouldn't surprise me if this was a factor in manufacturers choosing to switch to the current design for low floor vehicles. (Some buses on the continent have glider doors in the centre, and when the bus is crush loaded they can open and close sort of "around" passengers stood in the doorway)

 

[Gostav]

It seems similar with Japanese buses which were popular in last century. Such folding door disadvantage is that it is difficult to seal, so wind noise and road noise and dust tend to enter through the doors when driving at speeds.

 

[Citistar]

The older style bi-fold doors tend to take up more space from the width of the door aperture when open which represents a problem when most accessibility ramps use the full width of the doorway. The bi-folding ones were better suited to opening in to the edges of shallow step spaces on step entrance buses.