Double deck carriages - worth it ?

[Haydn1971]

Putting aside all the issues re track clearance and such, has anyone actually sat and thought about the actual increase in seating capacity and loading performance given by double deck carriages in terms of carriage length vs space taken by stairways (and lifts of course for DDA).

Whilst something like a 26m long fully seated carriage may give theoretically something like 80 seats, how much would a twin deck yield ? 140 perhaps including space taken by stairs/lifts - could the design work around DDA and force people with mobility issues into a specific carriage ? Would you need double width end doors to load/unload quicky enough ?

 

[swt_passenger]

Yes people have thought about, and there have been recent threads about it. There has been a fairly detailed DfT/NR report, which basically concludes the seating increase is a much lower proportion that you suggest - they basically give double decker stock within UK gauge no chance.

I'd read the report first: http://webarchive.nationalarchives....railwhitepapersupportingdocs/provevalddtrains

Interestingly, in the latest Modern Railways HS2 articles they also suggest that they are NOT actively considering double deck stock for HS2 - as the capacity increase is not proportional. (This might surprise a few posters who, in the past, appear to have assumed that HS2 will operate DD stock as a matter of course, just because it can...)

 

[DJL]

You could substantially increase the available capacity by not having internal staircases or lifts and having double deck platforms instead.
Obviously there would need to be some kind of emergency ladder in case an evacuation is needed. How this would fair with various health & safety laws is an important question.

As for DDA rules - the easy solution to that is anyone with DDA requirements only use the bottom deck.
No lifts are needed.

 

[upnorth71]

If the aim is to increase line capacity in terms of passenger throughput, better to lengthen trains and/or increase the number of trains. Any double deck design is going to have longer station dwell times than a single deck design, OK if your system is not a high frequency service, but not good if you expect future growth in traffic.

 

[jopsuk]

generally speaking DD stock is a better idea on limited-stop services, where the dwell time of funnelling more people through the same number of doors is less of an issue

 

[starrymarkb]

I believe dutch stock has wheelchair spaces at the intermediate level over the bogie. Swiss stock has boarding and a toilets on the low floor lower deck

 

[HSTEd]

The primary reason that HS2 is not currently plotting DD stock as the baseline is because someone noticed there is really only one manufacturer [Alstom] which means that you would be unable to actually have a competition for production of sets. This is the same as the reason given for CAHSR.

The fact that SNCF have not ordered a single single deck high speed trailer since the first Duplex sets arrived is rather telling though.

 

[themiller]

I believe dutch stock has wheelchair spaces at the intermediate level over the bogie. Swiss stock has boarding and a toilets on the low floor lower deck

Intercity Bahn 2000 and Zuerich S-Bahn stock has boarding at a mezzanine level with steps down to the lower saloon. The upper deck which is accessed up a curving staircase is the only way to walk between coaches. The trolley has to be put in a lift to service the lower saloons. The fixed catering facilities are on the lower deck along with the toilets - I can't remember what the disabled toilet arrangements are but if anyone's interested I think I have a reference book somewhere with sectional views which should reveal all. I'm a little out of touch with the new EMU trains as I haven't travelled in one - yet!
--- old post above --- --- new post below ---

The primary reason that HS2 is not currently plotting DD stock as the baseline is because someone noticed there is really only one manufacturer [Alstom] which means that you would be unable to actually have a competition for production of sets. This is the same as the reason given for CAHSR.

The fact that SNCF have not ordered a single single deck high speed trailer since the first Duplex sets arrived is rather telling though.

Agreed that Alstom are the only European company with a DD HS train in their catalogue but Bombardier produce the Zefiro which is quoted to be capable of up to 380 kph and they have a product called Twindexx in service so a combination of the two shouldn't be too hard.
http://www.bombardier.com/en/transportation/products-services/rail-vehicles.html
For a bit of competition there's also Japan to look at where they have bi-levels on the Shinkansen metals!
http://www.khi.co.jp/english/rs/product/detail/pro_e4.html

 

[CC 72100]

generally speaking DD stock is a better idea on limited-stop services, where the dwell time of funnelling more people through the same number of doors is less of an issue

To be fair, the SNCF pretty much destroys this theory. We have double deck trains on high speed (TGV), on Regional semi-Intercity services, and on large parts of the Parisian suburban network. On the latter, it is used on the RER D (two wide end doors on each carriage) which is obviously as suburban as it comes, but also acts as a sort of 'express' metro between Stade De France - Gare du Nord - C. Les Halles - Gare de Lyon - before Southern Paris where things become quieter, first stop Créteil.

Interestingly enough, it is exactly the same door layout as used on the loco-hauled push-pull stock I used from Rouen to Paris in December, which was non-stop throughout having originally come from Le Havre.

On the RER A, the double-deck stock have 3 doors per carriage, which works well on the busy section.

The primary reason that HS2 is not currently plotting DD stock as the baseline is because someone noticed there is really only one manufacturer [Alstom] which means that you would be unable to actually have a competition for production of sets.

No longer true. Bombardier are producing the Regio 2N (2N = deux niveau = double-deck) at exactly the same time as Alstom are the Regiolis (also double-decked). This is the 'big' Intercity/ regional order which will all but kill off loco-hauled sets on many TER and (formerly Corail) Intercités services. It is interesting to see which regions choose which train - they've got exactly the same target market, although I understand that the Bombardier attempt is also being looked at by Transilien (SNCF Ile-de-France) for replacement of the V2N push-pull double deck loco-hauled sets. The idea of tomorrow's Intercity train being the same train underneath as inner-suburban stuff - bit different!

 

[HSTEd]

Regio 2N is not high speed though.
And the Japanese have abandoned DD trains in the face of falling passenger counts.

DDs are politically expedient though thanks to the capacity argument.

 

[CC 72100]

Regio 2N is not high speed though.

Nope - but the double-deck TGVs obviously are.

In short, I was trying to de-bunk the myth that DD is a specialised thing, used in specific situations only and available from just one train builder.

 

[87015]

generally speaking DD stock is a better idea on limited-stop services, where the dwell time of funnelling more people through the same number of doors is less of an issue

Pretty much the entire continent disagrees, deckers are used on stopping trains from Liege/Amiens to Constanta and no doubt beyond. Somewhere like Germany RE and RB trains are in the majority and continue to increase, dosto/146 sets replacing 440 sets on commuter turns out of Munich by the month.

 

[Loki]

Interestingly, in the latest Modern Railways HS2 articles they also suggest that they are NOT actively considering double deck stock for HS2 - as the capacity increase is not proportional.

So what if the capacity is not proportional? How would a single decker be a better option for the captive services?

(This might surprise a few posters who, in the past, appear to have assumed that HS2 will operate DD stock as a matter of course, just because it can...)

I in particular have assumed the captive sets could be DD because DfT said they could.

 

[talltim]

So what if the capacity is not proportional? How would a single decker be a better option for the captive services?




I in particular have assumed the captive sets could be DD because DfT said they could.

There's a difference between could and would

 

[WatcherZero]

40% extra capacity from DD outweighs 40% longer trains in most assessments where it is feasible to provide.

 

[edwin_m]

From an HS2 point of view, most of the peak time trains are already proposed to be at the maximum 400m length assumed by European standards, and longer trains probably aren't an option because of the space constraints at many of the planned stations.

It is prudent for HS2 to plan on using single deck stock and keep the double deck option "in the back pocket" in case demand projections neaer to opening date suggest that overcrowding is likely. With the trains built to Euro-standards they could even buy single decks initially and sell them on to replace by double deck if there was overcrowding in service. This does of course only apply to the captive units, the classic compatibles would have to be single deck.

 

[Peter Mugridge]

Whilst something like a 26m long fully seated carriage may give theoretically something like 80 seats, how much would a twin deck yield ? 140 perhaps including space taken by stairs/lifts - ?

The trailer carriages on the Paris area Z20500 class ( my favourite double deckers ) seat 204 each; the driving motors seat 110 each ( the end part behind the cab is taken up with the motors because there is no room under the floor as the lower deck is, well, very low slung ).

 

[RichmondCommu]

generally speaking DD stock is a better idea on limited-stop services, where the dwell time of funnelling more people through the same number of doors is less of an issue

DD stock works very well in Sydney regardless of whether the trains are limited-stop services. However there does tend to be a slight delay when boarding as people make a decision on which deck gives them the best chance of getting a seat!

 

[jopsuk]

but DD isn't used on true Metros generally- eg in Paris it is used on RER but not Metro.

 

[RichmondCommu]

The primary reason that HS2 is not currently plotting DD stock as the baseline is because someone noticed there is really only one manufacturer [Alstom] which means that you would be unable to actually have a competition for production of sets. This is the same as the reason given for CAHSR.

The fact that SNCF have not ordered a single single deck high speed trailer since the first Duplex sets arrived is rather telling though.

You could also say the same for DB and their single deck ICE trains.
--- old post above --- --- new post below ---

but DD isn't used on true Metros generally- eg in Paris it is used on RER but not Metro.

Central Sydney is very much a true Metro service right from Central to North Sydney (and Circular Quay).

 

[themiller]

but DD isn't used on true Metros generally- eg in Paris it is used on RER but not Metro.

I'm just trying to imagine double-deck on the London Underground.
I think the reason why DD isn't used on "true Metros" is probably more to do with the existing infrastructure than anything else!

 

[DownSouth]

The primary reason that HS2 is not currently plotting DD stock as the baseline is because someone noticed there is really only one manufacturer [Alstom] which means that you would be unable to actually have a competition for production of sets. This is the same as the reason given for CAHSR.

That's not a reason, that's a lame excuse.

The HS2 captive set order will be a rather large order, large enough to prompt other companies like Bombardier or Siemens to develop a product combining their existing expertise in both DD stock and multi-level stock. Hopefully there would be some back-channel contact strongly encouraging Hitachi to dust off the E4 Series Shinkansen plans and make a TSI version - a healthy incentive for adding economic activity within Britain (i.e. assembly) should help there.

The Bombardier MultiLevel Coach mark II is already used at speeds of up to 200 km/h on the Northeast Corridor in the USA. As this is fitted with mid-level doors and vestibule sections for high level platforms (similar to a Sydney and Dutch stock) it would probably be the best point for Bombardier to start development on a HS version.

DD stock works very well in Sydney regardless of whether the trains are limited-stop services. However there does tend to be a slight delay when boarding as people make a decision on which deck gives them the best chance of getting a seat!

It's well worth it though. The roughly 40% increase in capacity more than balances out the slightly longer dwell times and the regular users tend to do a good job of keeping the sluggards moving along.

The increased total capacity (people per hour, not trains per hour) makes double-deck EMUs a winner for any sensibly organised transport system. Whether it will work in Britain where there is an aversion to good connections in favour of irrational timetables with convoluted "direct" trains is a different matter.

40% extra capacity from DD outweighs 40% longer trains in most assessments where it is feasible to provide.

I agree, mainly because if the extra capacity proves insufficient then you can go from short DD trains to long DD trains (as an option specified in the original specification) much more simply than tendering for the design and construction of a completely new order.

It is prudent for HS2 to plan on using single deck stock and keep the double deck option "in the back pocket" in case demand projections neaer to opening date suggest that overcrowding is likely. With the trains built to Euro-standards they could even buy single decks initially and sell them on to replace by double deck if there was overcrowding in service. This does of course only apply to the captive units, the classic compatibles would have to be single deck.

What a load of cobblers! It would be prudent to go with shorter DD sets from the start, with adding capacity being as simple as ordering extra intermediate cars to be inserted into each set, or coupling them together as is already done with pairs of TGV Duplex sets. This option would allow the improved energy efficiency of DD to be enjoyed immediately, and improvements in usage levels would not require the replacement of perfectly functional rolling stock.

Any public knowledge of such a plan would make it very hard to secure the necessary finance for the initial SD sets, the financiers would need to factor in the very real possibility that nobody else would want hand-me-down rolling stock from Britain which might need to be refurbished to meet their needs rather than those of the British who specified the trains in the first place.

--- old post above --- --- new post below ---

I'm just trying to imagine double-deck on the London Underground.
I think the reason why DD isn't used on "true Metros" is probably more to do with the existing infrastructure than anything else!

The difference between a Metro and heavy rail is that a Metro is for predominantly standing passengers and doesn't require timetables, while heavy rail only has standing passengers during peak loads.

I wouldn't call the inner end of Sydney's heavy rail routes a true Metro, you still need to rely on timetables.

 

[jopsuk]

I'm just trying to imagine double-deck on the London Underground.
I think the reason why DD isn't used on "true Metros" is probably more to do with the existing infrastructure than anything else!

Paris has built all-new Metro lines, stuck with single deck.

As for high-speed, the Japanese have done little more than dabbling in double decker stock, using it only where it is the only way to achieve the capacity needed.

 

[thelem]

I agree, mainly because if the extra capacity proves insufficient then you can go from short DD trains to long DD trains (as an option specified in the original specification) much more simply than tendering for the design and construction of a completely new order.

Only if you've already built your platforms long enough for the longer trains. Depending on the choice of station site, it may not even be possible to make the platforms longer.