Double decker trains

[Jozhua]

You're basically describing the Bombardier Omneo product currently being introduced by SNCF and the French regions for TER services (and eventually for Intercités and some Paris Suburban routes.)

Link is to the Bombardier Omneo Wikipedia page in English.

TER = Transport Express Régional - Regional Express Transport

As it appears, yes! In fact the design looks much better than my quick scrawls, having shorter single level carriages to allow for even more two floor space and shared bogies, which further reduces space and increases safety.

The design is still quite a bit out of UK loading gauges from what I can tell, although it looks like it has been designed to maximise the french loading gauge as it advertises itself as wider than the average french double-decker train.

Anyway, so I did a bit of poking around to see if I could compare the specifications of this train to the loading gauges of the UK. Although for the most part it seems quite restrictive, there are different classifications, with different areas of the network having larger gauges. These are all classified as "WX" something, with W6 being the most common, but a suprising amount of the network conforming to the W10 standard:
https://cdn.networkrail.co.uk/wp-co...nced-W10-loading-gauge-map-of-the-network.pdf

Still the W10 standard allows trains to be 2.9 meters high and 2.5 meters wide, which is still short of what most bi-level trains around the world conform to. Even on Japan's narrow gauge rail network, their trains are still able to be both wider (4.1 meters high and 3 meters wide) and taller than ours, even though they are limited to 75mph.
Even the most liberal UK standard, W12, is still just 2.9 meters high and 2.6 meters wide.

Unfortunately, our network still falls a meter short on height and half a meter short on width, so we really are significantly limited, unless some breakthrough space saving designs can be created. Obviously as well, the loading gauge is likely not a strict square and the shape of the gauge could allow for some deviations here and there, although I couldn't find any particular diagrams. Maybe some newly re-worked routes may be suitable as well as the newer HS1 and Crossrail networks.

 

[dazzler]

As it appears, yes! In fact the design looks much better than my quick scrawls, having shorter single level carriages to allow for even more two floor space and shared bogies, which further reduces space and increases safety.

The design is still quite a bit out of UK loading gauges from what I can tell, although it looks like it has been designed to maximise the french loading gauge as it advertises itself as wider than the average french double-decker train.

Anyway, so I did a bit of poking around to see if I could compare the specifications of this train to the loading gauges of the UK. Although for the most part it seems quite restrictive, there are different classifications, with different areas of the network having larger gauges. These are all classified as "WX" something, with W6 being the most common, but a suprising amount of the network conforming to the W10 standard:
https://cdn.networkrail.co.uk/wp-co...nced-W10-loading-gauge-map-of-the-network.pdf

Still the W10 standard allows trains to be 2.9 meters high and 2.5 meters wide, which is still short of what most bi-level trains around the world conform to. Even on Japan's narrow gauge rail network, their trains are still able to be both wider (4.1 meters high and 3 meters wide) and taller than ours, even though they are limited to 75mph.
Even the most liberal UK standard, W12, is still just 2.9 meters high and 2.6 meters wide.

Unfortunately, our network still falls a meter short on height and half a meter short on width, so we really are significantly limited, unless some breakthrough space saving designs can be created. Obviously as well, the loading gauge is likely not a strict square and the shape of the gauge could allow for some deviations here and there, although I couldn't find any particular diagrams. Maybe some newly re-worked routes may be suitable as well as the newer HS1 and Crossrail networks.

Aye, the Omneo design is way out of the UK loading gauge, I was just using it as an example of a train which is already available, but I'm sure you realise this.

Sadly, I don't think it could be successfully "shrunk" to fit the UK loading gauge, as European loading gauges tend to be the same width all the way to just above rail level, whereas the UK gauge curves in sharply just above platform level and is a lot narrower down to rail level. To adapt the design for the UK, a lot of ground based signalling and permanent way equipment would have to be moved/removed for the lower deck to be wide enough for more than 1+1 seating.

 

[Jozhua]

Aye, the Omneo design is way out of the UK loading gauge, I was just using it as an example of a train which is already available, but I'm sure you realise this.

Sadly, I don't think it could be successfully "shrunk" to fit the UK loading gauge, as European loading gauges tend to be the same width all the way to just above rail level, whereas the UK gauge curves in sharply just above platform level and is a lot narrower down to rail level. To adapt the design for the UK, a lot of ground based signalling and permanent way equipment would have to be moved/removed for the lower deck to be wide enough for more than 1+1 seating.

Who knows, 1+1 seating sounds pretty appealing to me!

So strange how Japan has narrower track gauges and wider/taller loading gauges, almost seems like a recipe for toppling over. Or is just a good example of how restrictive the UK loading gauge is.

There are suggestions, however, to upgrade the GB+ standard the channel tunnel is built to to the Midland Main Line, I only see this benefiting freight though, as the Thameslink services also run on the 3rd rail network. MML Express services probably don't require much capacity boost beyond adding more carriages, which can be easily done with current infrastructure.

I think in regards to loading gauges, there is a very small overlap between lines that can be upgraded for reasonable standards to allow for a double decker advantage and those which double-decker trains would bring an advantage over longer services. The whole 3rd rail network comes to mind as the platform lengths and power-draw issues of longer trains could be resolved with being able to increase passenger to weight ratio, but this would probably be the hardest area to implement it!

 

[themiller]

There are suggestions, however, to upgrade the GB+ standard the channel tunnel is built to to the Midland Main Line,

The channel tunnel is considerably larger than GB+. It’s the loading gauge onward into France that is GB+.

 

[Jozhua]

The channel tunnel is considerably larger than GB+. It’s the loading gauge onward into France that is GB+.

Well that's just being a bit pedantic isn't it , the point was that Network Rail was looking at expanding the wider loading gauge to some other lines in the country.

The main issue with width, however is that the platforms would need to be further away from the tracks, introducing difficulties loading onto existing trains. The only solution I can think of is that trains could either be built or retrofitted with fold-able steps which bridge the gap a good 20cm or so similar to how voyagers have the folding down steps. Or perhaps if they run entirely in a GB+ area, the steps could be fixed on permanently.

 

[AM9]

Well that's just being a bit pedantic isn't it , the point was that Network Rail was looking at expanding the wider loading gauge to some other lines in the country.

The main issue with width, however is that the platforms would need to be further away from the tracks, introducing difficulties loading onto existing trains. The only solution I can think of is that trains could either be built or retrofitted with fold-able steps which bridge the gap a good 20cm or so similar to how voyagers have the folding down steps. Or perhaps if they run entirely in a GB+ area, the steps could be fixed on permanently.

No, platform edges aren't the main issue. The biggest and most intractable problem is the sheer number of structural intrusions into the below floor area of vehicles, mainly being plate girder under bridges. Where there is plenty of clearance beneath the trackbed, the girder trusses are mounted beneath the track. However, standard practice in the UK has been to rise the trusses between tracks which usually means that there is just enough room for bogies to pass through. This removes any scope for designing passenger space below platform level.
Here is a picture showing a typical complex plate girder bridge with trusses between closely spaced tracks:
https://images.app.goo.gl/2o5GWBQYSyNTm6CPA
There are hundreds of bridges just like that, - especially on the approaches to London termini. Removing them would be prohibitively disruptive and expensive especially to only get a possible increase in route capacity.

 

[JonasB]

The only solution I can think of is that trains could either be built or retrofitted with fold-able steps which bridge the gap a good 20cm or so similar to how voyagers have the folding down steps.

That could have been an excellent way to use the old Eurostar trains.

 

[Jozhua]

No, platform edges aren't the main issue.
There are hundreds of brides just like that, - especially on the approaches to London termini. Removing them would be prohibitively disruptive and expensive especially to only get a possible increase in route capacity.

However, standard practice in the UK has been to rise the trusses between tracks which usually means that there is just enough room for bogies to pass through. This removes any scope for designing passenger space below platform level.

I mentioned that the main issue in "regards to width" was platform edges and didn't mention anything about height

According to Network rail they think they might be able to expand GB+ to the Midland Mainline so perhaps the bridges don't generally fall too victim to this issue...

It definitely seems like they are going through and making gauge improvements as and when they carry out work on infrastructure, such as replacing signals and building new tunnels/alignments. It definitely appears to be a very gradual rate of progress, but one that freight is eager for so there is definitely the incentive to create the conditions needed for bi-level rail cars.

In regards to my retractable step theory, some sort of solution may be needed for "classic compatible" trains on the HS2 network, so that they can use the new platforms as well as existing ones. Anyone got any ideas if a bi-level bid is likely to succeed in regards to HS2 rolling stock, I saw an article on it about a year ago, but not heard anything after that.

 

[AM9]

I mentioned that the main issue in "regards to width" was platform edges and didn't mention anything about height

According to Network rail they think they might be able to expand GB+ to the Midland Mainline so perhaps the bridges don't generally fall too victim to this issue...

It definitely seems like they are going through and making gauge improvements as and when they carry out work on infrastructure, such as replacing signals and building new tunnels/alignments. It definitely appears to be a very gradual rate of progress, but one that freight is eager for so there is definitely the incentive to create the conditions needed for bi-level rail cars.

In regards to my retractable step theory, some sort of solution may be needed for "classic compatible" trains on the HS2 network, so that they can use the new platforms as well as existing ones. Anyone got any ideas if a bi-level bid is likely to succeed in regards to HS2 rolling stock, I saw an article on it about a year ago, but not heard anything after that.

I think that you have misunderstood whay I have said in post No. #96. I didn't mention gauge height. I referred to "under bridges" as in bridges that have road, rail or water underneath them. The linked picture is of Borough Market Junction which is over roads, and a market place. You can see in the picture that there are plate girder trusses located in the 6 foot that rise above rail level. A similar situation is present on bridges over the B530 Ampthill Road, the adjacent Marston Vale line, Lovell/Oakley Road, Podington Road (Wymington), and probably others. These intrusions into the below floor area of the gauge prevent any expansion of a passenger beyong the existing wheel height width. Thus as others have said, a lower floor area would just about be able to accomodate a 1+1 seating plan, i.e. not worth bothering.

 

[hwl]

I think that you have misunderstood whay I have said in post No. #96. I didn't mention gauge height. I referred to "under bridges" as in bridges that have road, rail or water underneath them. The linked picture is of Borough Market Junction which is over roads, and a market place. You can see in the picture that there are plate girder trusses located in the 6 foot that rise above rail level. A similar situation is present on bridges over the B530 Ampthill Road, the adjacent Marston Vale line, Lovell/Oakley Road, Podington Road (Wymington), and probably others. These intrusions into the below floor area of the gauge prevent any expansion of a passenger beyong the existing wheel height width. Thus as others have said, a lower floor area would just about be able to accomodate a 1+1 seating plan, i.e. not worth bothering.

Agreed platforms may be numerous but most can be relatively cheaply be adjusted, the real cost comes for underbridges and the real fun platforms on top of problem under bridges...
The UK lower structure gauge is effectively defined by underbridges not platforms.

 

[AM9]

Agreed platforms may be numerous but most can be relatively cheaply be adjusted, the real cost comes for underbridges and the real fun platforms on top of problem under bridges...
The UK lower structure gauge is effectively defined by underbridges not platforms.

I wonder if the UK's propensity for double-deck buses has played a part in the number of bridges being like that. It seems from pictures of plate girder truss/beam bridges that most of them have the support entirely below track level giving a clear flat deck for the formation. This requires the full depth of the truss to be accommodated below the deck requiring anything from 1-3 metres depending on the span. In some urban locations, getting sufficient clearance for double-deck buses might not easily be achievable. So the track configuration is locked by the siting of the bridge components forever (for the life of the bridge anyway).

 

[hwl]

I wonder if the UK's propensity for double-deck buses has played a part in the number of bridges being like that. It seems from pictures of plate girder truss/beam bridges that most of them have the support entirely below track level giving a clear flat deck for the formation. This requires the full depth of the truss to be accommodated below the deck requiring anything from 1-3 metres depending on the span. In some urban locations, getting sufficient clearance for double-deck buses might not easily be achievable. So the track configuration is locked by the siting of the bridge components forever (for the life of the bridge anyway).

Agreed - the only real gains are usually replacing the oldest iron decks or early (plate) steel pre WW1. The current favourite composite steel - concrete decks seem the best way of getting clearances both ways.

 

[Bald Rick]

Agreed platforms may be numerous but most can be relatively cheaply be adjusted, the real cost comes for underbridges and the real fun platforms on top of problem under bridges...
The UK lower structure gauge is effectively defined by underbridges not platforms.

The real cost of having wider trains is not the platforms, or the bridges, but having to move all tracks* further apart from each other to avoid trains colliding when they pass. Which in turn means moving almost all signals, and all the OLE. Or, effectively, building a new railway.

* except in single track areas, obviously.

 

[HSTEd]

It is likely that the cheapest way to get double decker trains is not to clear to GB+, with all the lower structural issues, but probably adopt a bespoke taller gauge that is the same as the current one below the solebar.

Have to rebuild even more overbridges but you avoid all the problems at ground level.

 

[MarlowDonkey]

You wonder what might have happened if Brunel had stuck with Stephenson's distance between the rails, but went for much wider and higher carriages and wagons. As it was I believe his 7ft carriages weren't much wider than their "narrow gauge" equivalents.

I suppose the last passenger stock to take advantage of Brunel's dimensional leftovers are the 165/166 units. These fit 3+2 seating while their electric replacements in the London area, the 387s can only manage 2+2 and don't look as if there's space for any more, given the sloping inwards bodywork.

 

[swt_passenger]

These fit 3+2 seating while their electric replacements in the London area, the 387s can only manage 2+2 and don't look as if there's space for any more, given the sloping inwards bodywork.

That’s wrong I’m afraid. 387s have just the same body and interior dimensions as the older 375, 377 and 379, and there are many in service variants with 2+3 seating. 387s being 2+2 was a good decision, but it wasn’t because of body shape.

 

[AM9]

It is likely that the cheapest way to get double decker trains is not to clear to GB+, with all the lower structural issues, but probably adopt a bespoke taller gauge that is the same as the current one below the solebar.

Have to rebuild even more overbridges but you avoid all the problems at ground level.

That would make passenger cars almost as high as double stack containers. OK for freight ambling along at 60mph on very long journeys, but a totally different proposition with self-movable passenger loads at speeds over 100. Also, really tall double-deck cars can have almost continuous sway, - I know, I spent 22 hrs on the Rocky Mountaineer in June (long enough to get 'sea legs'); and then had nearly 24hours of 'dock rock' after getting off. That's why the RM only does 60-70 on flat straight bits.

 

[HSTEd]

That would make passenger cars almost as high as double stack containers.

TGV Duplex has an internal floor height of ~300mm above rail.
That implies about 4m of height above the floor is necessary.

If we take a typical UK floor height of 1100mm above rail, that only implies the train will be 800mm taller than a TGV Duplex.

Which puts us about 5100mm.

GC gauge is 4650mm high, which means we have gained about 450mm above normal European practice. About 16".

The smallest double stack loading gauge used in the US is about 5540mm of vertical clearance, and they recommend over 6m for new routes.

It's only 8" taller than a Superliner, which are cleared for 100mph operations on rather poor track by European standards.

I am not convinced that it is really a major issue.
Especially since there will be a lot of heavy equipment below the solebar anyway, since we have plenty of room there unlike in a container train.

OK for freight ambling along at 60mph on very long journeys, but a totally different proposition with self-movable passenger loads at speeds over 100. Also, really tall double-deck cars can have almost continuous sway, - I know, I spent 22 hrs on the Rocky Mountaineer in June (long enough to get 'sea legs'); and then had nearly 24hours of 'dock rock' after getting off. That's why the RM only does 60-70 on flat straight bits.

The Rocky Mountaineer runs on relatively low standard track in mountainous terrain though, its a bit different to the typical standard of EUropean or British railways!

Also apparently the Rocky Mountaineer's Ultra Dome Cars are 5500mm tall, so as far from my proposed gauge as the GC gauge used on the continent is!

EDIT:

Apparently the Skoda Transtech double deck coaches on Finnish railways have a height of 5200mm, so more than I proposed.
Whilst they have a wider gauge, it is not that much wider.
As a multiple of the rail gauge, that is comparable to what I propose.

 

[AM9]

TGV Duplex has an internal floor height of ~300mm above rail.
That implies about 4m of height above the floor is necessary.

If we take a typical UK floor height of 1100mm above rail, that only implies the train will be 800mm taller than a TGV Duplex.

Which puts us about 5100mm.

GC gauge is 4650mm high, which means we have gained about 450mm above normal European practice. About 16".

The smallest double stack loading gauge used in the US is about 5540mm of vertical clearance, and they recommend over 6m for new routes.

It's only 8" taller than a Superliner, which are cleared for 100mph operations on rather poor track by European standards.

I am not convinced that it is really a major issue.
Especially since there will be a lot of heavy equipment below the solebar anyway, since we have plenty of room there unlike in a container train.

The Rocky Mountaineer runs on relatively low standard track in mountainous terrain though, its a bit different to the typical standard of EUropean or British railways!

Also apparently the Rocky Mountaineer's Ultra Dome Cars are 5500mm tall, so as far from my proposed gauge as the GC gauge used on the continent is!

EDIT:

Apparently the Skoda Transtech double deck coaches on Finnish railways have a height of 5200mm, so more than I proposed.
Whilst they have a wider gauge, it is not that much wider.
As a multiple of the rail gauge, that is comparable to what I propose.

I'm not convinced that double deck trains, will do anything much for high capacity services, unless either stops are at least 20 minutes apart, or dwell times aren't an issue, ( in which case it isn't really a high capacity railway)

 

[HSTEd]

I'm not convinced that double deck trains, will do anything much for high capacity services, unless either stops are at least 20 minutes apart, or dwell times aren't an issue, ( in which case it isn't really a high capacity railway)

That might be the case in terms of the compact trains we see in Europe, but remember since we have a floor level above the bogies, we can have walk through corridors on both floors. This allows us to do interesting things to maximise passenger loading.

Imagine if you will a 5-car set on Transpennine (as a random example of a route, not suggesting this would be easily deployable there or anything).
There is a mix of people making longer journeys as well as people making relatively short hops, if we had a fixed formation we would only need two or maybe three staircases in the five car set, so the loss of floor area to stairs is negligible.
We can provide a commuter style layout in the lower deck with lots of standing room and seats packed in with no tables, whilst also providing a longer distance suitable layout on the upper deck.
Especially given we can have full width gangways on both levels.

Also remember that since we can do this, the train can start moving before everyone is necessarily seated, once everyone is aboard it doesn't matter if they are still climbing the stairs out of the voluminous vestibules.

We can provide three doors per side in the style of the London Underground without eating up all the passenger space, if nothing else.

 

[AM9]

That might be the case in terms of the compact trains we see in Europe, but remember since we have a floor level above the bogies, we can have walk through corridors on both floors. This allows us to do interesting things to maximise passenger loading.

Imagine if you will a 5-car set on Transpennine (as a random example of a route, not suggesting this would be easily deployable there or anything).
There is a mix of people making longer journeys as well as people making relatively short hops, if we had a fixed formation we would only need two or maybe three staircases in the five car set, so the loss of floor area to stairs is negligible.
We can provide a commuter style layout in the lower deck with lots of standing room and seats packed in with no tables, whilst also providing a longer distance suitable layout on the upper deck.
Especially given we can have full width gangways on both levels.

Also remember that since we can do this, the train can start moving before everyone is necessarily seated, once everyone is aboard it doesn't matter if they are still climbing the stairs out of the voluminous vestibules.

We can provide three doors per side in the style of the London Underground without eating up all the passenger space, if nothing else.

Are there any examples of double deck rolling stock with gangways about 2 metres abiove coupling height?

 

[Chris125]

You wonder what might have happened if Brunel had stuck with Stephenson's distance between the rails, but went for much wider and higher carriages and wagons. As it was I believe his 7ft carriages weren't much wider than their "narrow gauge" equivalents.

Thankfully there was no real need - it would have made 'mixed gauge' lines and the transition to standard gauge much more difficult.

 

[themiller]

Are ther any examples of double deck rolling stock with gangways about 2 metres abiove coupling height?

http://www.bahnonline.ch/bo/52822/d...2000-fahrzeuge-sind-komplett-modernisiert.htm Not 2 metres but about 1metre if you look at the 5th picture in the link.

 

[jopsuk]

Are ther any examples of double deck rolling stock with gangways about 2 metres abiove coupling height?

Amtrak Superliners have the corridor connector on the upperdeck, as do the California Cars/Surfliners. The latter are derived from the Superliner, but are all days coaches with two vestibules downstairs for services with shorter more frequent stops.

 

[Ethano92]

I'm not convinced that double deck trains, will do anything much for high capacity services, unless either stops are at least 20 minutes apart, or dwell times aren't an issue, ( in which case it isn't really a high capacity railway)

I'm not convinced dwell times will be a massive issue after travelling on TER yesterday. The shortest stop was only 3 minutes, the longest was 24 minutes.

I admit that for a UK guage train, the desiro City fleet has wide doors and a large lobby but they're nothing compared to the lobbies of some trains on the continent. There was also clearly a habit of making your way down to the lobby in time for your stop as without fail the doors opened within <2 seconds of the train coming to a halt.

Dwell times were just as short as my earlier journeys with SWR to Clapham and Southern to Gatwick.

Finally, similar to double decker buses which we're fairly good at, if you're going a few stops, stay downstairs or near stairs on the top deck. If you're going for longer you can make your way well into the top deck.

 

[HSTEd]

Are there any examples of double deck rolling stock with gangways about 2 metres abiove coupling height?

As has been stated, American stock is relatively good for this.
The upper deck gangway is basically as high as it can be without fouling the roofline, so is at a comparable height to what we are talking about.

Also we actually potentially gain passenger area because whilst we need two or three staircases per set, we get a full second deck but don't need to duplicate the cabs or disabled toilets. (Not much point of a wheelchair compatible toilet on the upper deck is there!)

EDIT:

Stadler claims the coaches it built for the Rocky Mountaineer are also good to 110mph!

 

[AM9]

Apart from HS2 (and HS1 if needed) double deck in the UK just won't happen and not necessary.

 

[HSTEd]

Apart from HS2 (and HS1 if needed) double deck in the UK just won't happen and not necessary.

If HS2 Ltd got their way there will never be a double deck train on HS2 because their insane platform specification has rendered it impractical. Still trying to figure out what happened in the end.

But I would argue about it is very necessary, large parts of the network are creaking at the seams and new line construction turns out to be astronomically expensive.
Unless they can make new lines cost something like they do on the continent, there will be no more new construction beyond HS2-2a (and that might be optimistic)

 

[JKF]

I would imagine you will need stairs in each carriage just for safety purposes - in the event of an accident where the coach with stairs becomes crushed or engulfed in flames there has to be some other means of egress from the other carriages, as dropping several metres from an upper window won’t be safe. Could be done aircraft style with inflatable stairs I suppose!

 

[JKF]

& a more elaborate solution to dwell times would be having platforms on either side of the train at different heights, with the upper level detraining on one side and lower on the other. Plenty of issues with this I can think of though...