Bi-Mode rolling stock and passenger saloon height

[Clansman]

Just a quick wee query in regards to this, as I'm no expert on the mechanics of rolling stock!

As is widely known, the design of the IETs is such that the bi-mode nature requires raised flooring in the intermediate carriages to allow the space required for the underfloor engines. But as seen with the 319 bi/tri-mode conversion, there isn't the same issue, and as such, the floor height remains lower thus allowing the passenger saloon to feel much more open.

What are the reasons for this? Is it the fact that engines which require greater acceleration and speed require the greater amount of space, or is it just down to the design of the engine itself in relation to the manufacturer? Though with the prospect of 385s receiving their own battery packs or diesel engines in future trials, this theory wouldn't stack up surely?

To generalise, could the raised flooring of the IETs have been prevented in this regard - or am I missing something?

 

[43096]

Just a quick wee query in regards to this, as I'm no expert on the mechanics of rolling stock!

As is widely known, the design of the IETs is such that the bi-mode nature requires raised flooring in the intermediate carriages to allow the space required for the underfloor engines. But as seen with the 319 bi/tri-mode conversion, there isn't the same issue, and as such, the floor height remains lower thus allowing the passenger saloon to feel much more open.

What are the reasons for this? Is it the fact that engines which require greater acceleration and speed require the greater amount of space, or is it just down to the design of the engine itself in relation to the manufacturer? Though with the prospect of 385s receiving their own battery packs or diesel engines in future trials, this theory wouldn't stack up surely?

It's the size of the engines that dictates the floor height, not that they are bi-mode as such. Obviously the 319 conversions can't raise the floor height, which constrains engine size and consequently power.

 

[hwl]

Just a quick wee query in regards to this, as I'm no expert on the mechanics of rolling stock!

As is widely known, the design of the IETs is such that the bi-mode nature requires raised flooring in the intermediate carriages to allow the space required for the underfloor engines. But as seen with the 319 bi/tri-mode conversion, there isn't the same issue, and as such, the floor height remains lower thus allowing the passenger saloon to feel much more open.

What are the reasons for this? Is it the fact that engines which require greater acceleration and speed require the greater amount of space, or is it just down to the design of the engine itself in relation to the manufacturer? Though with the prospect of 385s receiving their own battery packs or diesel engines in future trials, this theory wouldn't stack up surely?

To generalise, could the raised flooring of the IETs have been prevented in this regard - or am I missing something?

IETs have a v12, 769 has a horizontal orientation straight 6 (like every thing 150-197 and 220-222)
The V12 needs much more height.

The v12 can provide upto 940hp but the straight 6s are in the range 285-750hp

 

[stuu]

There is, unless I am not very perceptive, no difference in the look/openness of IET cars with and without engines. I am aware they are different but its not noticeable

 

[ABB125]

IETs have a v12, 769 has a horizontal orientation straight 6 (like every thing 150-197 and 220-222)
The V12 needs much more height.

The v12 can provide upto 940hp but the straight 6s are in the range 285-750hp

Are "flat" engines ever used (eg: 3 cylinders to the left, 3 to the right, effectively a straight six but with every other cylinder 180 degrees opposite)? I would have thought that they would be a better option than a "normal" engine on its side, as presumably straight engines are designed to be upright?

 

[Domh245]

Are "flat" engines ever used (eg: 3 cylinders to the left, 3 to the right, effectively a straight six but with every other cylinder 180 degrees opposite)? I would have thought that they would be a better option than a "normal" engine on its side, as presumably straight engines are designed to be upright?

Flat engines are much wider than inlines, which would prevent their use in most cases I'd think. Straights aren't necessarily designed to be upright (for example, BMW engines usually have a fair slant to them to reduce their effective height), and indeed I believe that most rail engines are designed for near flat operation. This page has some images of a 156 engine for example

 

[Philip Phlopp]

Flat engines are much wider than inlines, which would prevent their use in most cases I'd think. Straights aren't necessarily designed to be upright (for example, BMW engines usually have a fair slant to them to reduce their effective height), and indeed I believe that most rail engines are designed for near flat operation. This page has some images of a 156 engine for example

They tend to be a derivative of a standard upright engine (so same camshafts, valves, pistons, connecting rods, crankshaft etc) with a bespoke or heavily modified block and cylinder head suited to horizontal installation. They sometimes have the same ancillaries (oil and water pump etc) but can have bespoke parts if needed, particularly if the water or oil cooling circuits are longer.

 

[ABB125]

Flat engines are much wider than inlines, which would prevent their use in most cases I'd think. Straights aren't necessarily designed to be upright (for example, BMW engines usually have a fair slant to them to reduce their effective height), and indeed I believe that most rail engines are designed for near flat operation. This page has some images of a 156 engine for example

Thanks, interesting website. Seems like flat engines aren't really needed then!

 

[hwl]

They tend to be a derivative of a standard upright engine (so same camshafts, valves, pistons, connecting rods, crankshaft etc) with a bespoke or heavily modified block and cylinder head suited to horizontal installation. They sometimes have the same ancillaries (oil and water pump etc) but can have bespoke parts if needed, particularly if the water or oil cooling circuits are longer.

Most "horizontal" variants aren't actually horizontal but only 70-80 degrees from vertical so they are slightly inclined to minimise the number of components that need to be different from the standard vertical engines.

Thanks, interesting website. Seems like flat engines aren't really needed then!

A flat engine would be too wide for GB network's lower structure gauge (and heavier less efficient than a horizontal straight equivalent...)

Flat engines are much wider than inlines, which would prevent their use in most cases I'd think. Straights aren't necessarily designed to be upright (for example, BMW engines usually have a fair slant to them to reduce their effective height), and indeed I believe that most rail engines are designed for near flat operation. This page has some images of a 156 engine for example

The MTU V12 is a 90degree V angle so the banks are inclined at 45degrees.

 

[61653 HTAFC]

There is, unless I am not very perceptive, no difference in the look/openness of IET cars with and without engines. I am aware they are different but its not noticeable

I've never noticed a difference either. When the design was first announced, there was talk of sloping floors within vehicles to accommodate the engines, though this turned out to be inaccurate conjecture as far as I can tell.

 

[swt_passenger]

I've never noticed a difference either. When the design was first announced, there was talk of sloping floors within vehicles to accommodate the engines, though this turned out to be inaccurate conjecture as far as I can tell.

There’s a discussion somewhere that explains the slope is between the doors and the inter-car gangway, ie in the vicinity of the toilets and luggage compartments. So it isn’t noticeable if moving directly from a door to the seats.

 

[Bletchleyite]

I've never noticed a difference either. When the design was first announced, there was talk of sloping floors within vehicles to accommodate the engines, though this turned out to be inaccurate conjecture as far as I can tell.

The slope is up from the gangway connection, and there's a step up when entering the door.

Access aside, I prefer the high floor vehicles, the window is a better height to rest your elbow on the sill.

 

[Richard Scott]

I've never noticed a difference either. When the design was first announced, there was talk of sloping floors within vehicles to accommodate the engines, though this turned out to be inaccurate conjecture as far as I can tell.

There is a slope up into saloon, if I remember correctly. It is there if you look for it!

 

[61653 HTAFC]

There’s a discussion somewhere that explains the slope is between the doors and the inter-car gangway, ie in the vicinity of the toilets and luggage compartments. So it isn’t noticeable if moving directly from a door to the seats.

I've also passed between vehicles and not noticed a change, so presumably it's only a change of a few centimetres from low to high. The discussion before we'd seen them in the flesh seemed to suggest a more significant slope IIRC.

 

[Bletchleyite]

I've also passed between vehicles and not noticed a change, so presumably it's only a change of a few centimetres from low to high. The discussion before we'd seen them in the flesh seemed to suggest a more significant slope IIRC.

The height difference is about 5", if I recall.

 

[swt_passenger]

I've also passed between vehicles and not noticed a change, so presumably it's only a change of a few centimetres from low to high. The discussion before we'd seen them in the flesh seemed to suggest a more significant slope IIRC.

Yes I agree, there was certainly a suggestion before the trains arrived that you might need a Sherpa to help scale the heights...

 

[61653 HTAFC]

The height difference is about 5", if I recall.

Bigger than it looks, if I'm remembering right... I'll keep an eye out next time I'm on an 802.

 

[squizzler]

To generalise, could the raised flooring of the IETs have been prevented in this regard - or am I missing something?

Class 755 are amongst the lowest floor stock on the network - whose doors are level with the platforms - thus demonstrating that high floors are not inherent to bi-mode trains, even those purpose designed rather than converted from EMUs. As for the relevance of this to the OP, an early concept for the IET programme would also have involved separate generator cars (think of this arrangement, albeit an end car so as to resemble a class 43 in appearance).

 

[D365]

There is a slope up into saloon, if I remember correctly. It is there if you look for it!

Certain members made a huge fuss about this before the IET units were delivered, quite telling that I’ve not heard from them since...

 

[ABB125]

Certain members made a huge fuss about this before the IET units were delivered, quite telling that I’ve not heard from them since...

Can't say I've ever noticed it, but then again I haven't looked!

 

[Mordac]

Certain members made a huge fuss about this before the IET units were delivered, quite telling that I’ve not heard from them since...

Indeed, this was going to be like climbing a mountain.

 

[SussexLad]

I've never noticed a difference either. When the design was first announced, there was talk of sloping floors within vehicles to accommodate the engines, though this turned out to be inaccurate conjecture as far as I can tell.

I'm 6ft 4 and I've never noticed a difference. I think the IETs feel very open and modern (if you can get over the seats and leg room)

 

[Richard Scott]

Certain members made a huge fuss about this before the IET units were delivered, quite telling that I’ve not heard from them since...

It's certainly not something to make a fuss about.

 

[Bletchleyite]

I'm 6ft 4 and I've never noticed a difference. I think the IETs feel very open and modern (if you can get over the seats and leg room)

I'm the same height and it's one of the few types of stock where I will fit comfortably in all seats, other than a numb backside after half an hour!

 

[Energy]

To generalise, could the raised flooring of the IETs have been prevented in this regard - or am I missing something?

MTU allow you to mount the engine in the civitys on the roof which could allow the train to be lower floor. You would require more engines but 1 of the roof mounted engines per car would have more diesel power than a 800 due to not all the 800 cars having engines.

 

[D365]

I'm 6ft 4 and I've never noticed a difference. I think the IETs feel very open and modern (if you can get over the seats and leg room)

It's certainly not something to make a fuss about.

I'm the same height and it's one of the few types of stock where I will fit comfortably in all seats, other than a numb backside after half an hour!

Being 6'2, those are exactly my thoughts also.

 

[Philip Phlopp]

MTU allow you to mount the engine in the civitys on the roof which could allow the train to be lower floor. You would require more engines but 1 of the roof mounted engines per car would have more diesel power than a 800 due to not all the 800 cars having engines.

Only if loading gauge and platform height permits. You certainly ain't doing that in Britain...

 

[Domh245]

Only if loading gauge and platform height permits. You certainly ain't doing that in Britain...

Nor with a mechanical transmission, which based on the thread about DMU Vs DEMU, and CAFs 'usp' ain't happening technically either

 

[Rhydgaled]

Only if loading gauge and platform height permits. You certainly ain't doing that in Britain...

Not specific to bi-modes, but on the subject of saloon floor heights and platform heights I understand that the Anglia FLIRTs have a sort of metal plank thing that slides out to fill the gap between the train and the platform. If you put a similar sliding plank thing on a train with a standard floor height (say the 769s, because they are bi-mode) and increased the standard platform height to match, would that cause gauging issues through said raised platforms? And if you raised the platform height another 5in to match the class 800/801/802 saloon floor height would that cause problems?

 

[Bletchleyite]

Not specific to bi-modes, but on the subject of saloon floor heights and platform heights I understand that the Anglia FLIRTs have a sort of metal plank thing that slides out to fill the gap between the train and the platform. If you put a similar sliding plank thing on a train with a standard floor height (say the 769s, because they are bi-mode) and increased the standard platform height to match, would that cause gauging issues through said raised platforms? And if you raised the platform height another 5in to match the class 800/801/802 saloon floor height would that cause problems?

A higher platform height which would be roughly 80x floor height is being considered for HS2, but it causes issues for freight. Remember though that 80x have two floor heights which are about 4-5" different.