TGV duplex, would it fit through the channel tunnel?

[gsnedders]

That’s SNCF really wanting to stick with end power units.
That’s why it’s not an AGV, as the AGV has distributed power.

Would a double-deck AGV be able to fit within the axle weight limit with transformers and such on carriages?

 

[edwin_m]

Would a double-deck AGV be able to fit within the axle weight limit with transformers and such on carriages?

I don't think it would be a problem because the power cars are full of traction gubbins and manage to stay within the limit. If the traction equipment was located in passenger cars then some of those cars would remain as passenger space, so they would be lighter than the power cars. The absence of a distributed power double deck TGV may be more about the fact that there is no spare space in a double deck vehicle so any traction equipment would reduce passenger space, unlike a single deck where it can go under the floor or perhaps above the ceiling.

 

[rf_ioliver]

I find it interesting that the EU, governments, etc. insist on a free market and competition, but when parts of the free market decide to merge to improve their competitiveness, they get jittery.

There are well defined rules both in the EU and internationally regarding free market, competition etc.

However when two [large] companies merge, especially in an industry where there is relatively little competition then regulators of various governments are very right to get involved to prevent monopolies and cartels forming. So in this case, yes, the EU (and the various national goverments) are very right to get "jittery"

Wikipedia has a good summary of UK law in this respect: https://en.wikipedia.org/wiki/United_Kingdom_competition_law

t.

Ian

 

[LLivery]

That’s SNCF really wanting to stick with end power units.
That’s why it’s not an AGV, as the AGV has distributed power.

Ah, makes sense. This there any particular reason? Surely it's not the BR style rules where trains basically had to be loco hauled over 100mph/160kph as they allow Velaros on their metals.

 

[AlexNL]

My guess: it maximised interior space available to passengers, providers a more quiet ambiance due to no traction equipment being under the coaches, and it makes maintenance easier as power cars can be swapped around without having to take the entire set out of service.

Pretty much what people love about IC125's

 

[MarkyT]

I don't think it would be a problem because the power cars are full of traction gubbins and manage to stay within the limit. If the traction equipment was located in passenger cars then some of those cars would remain as passenger space, so they would be lighter than the power cars. The absence of a distributed power double deck TGV may be more about the fact that there is no spare space in a double deck vehicle so any traction equipment would reduce passenger space, unlike a single deck where it can go under the floor or perhaps above the ceiling.

The ever changing fashions with respect to distributed versus centralised drive configuration in high speed operations may also be related to European standard platform heights and the desire for level boarding. Floor heights in 'traditional' very high speed distributed drive units, as offered by Japanese manufacturers and Siemens, are fairly high, at around 1200mm, while the highest standard platform allowed by EU TSIs is 760mm. This means a step or two up into the passenger cars of these traditional HS units is inevitable, which is not ideal from a PRM perspective nor for fast boarding generally. Talgo and Alstom, with their latest 'motrice' (power car) configurations, can both offer lower floors to match the TSI platforms, as they don't have to accommodate bulky power bogies or axles beneath the passenger vehicles. HS2 are intending to use a higher Japanese style platform at approx. 1150mm, that could allow level boarding to be compatible with all manufacturers' products as well as permitting a reasonable vertical gap for 'classic compatibles' when running on UK legacy infrastructure, but the EU are not minded to allow such a TSI variation, not that their opinion may matter very much shortly. Stadler have yet to move into the very high speed market but are currently delivering EC250 trains to SBB which are capable of 250kph and will be used on long distance intercity routes through the new Gotthard base tunnel. These have 760mm internal floor height so are fully TSI compliant with level boarding. As to drive configuration, they are similar to the same manufacturer's FLIRTs, without dedicated 'power only' cars but with a limited number of power bogies accommodated under sections of passengers cars with floor height raised locally. It is possible they may attempt a 300/350kph unit with a similar configuration in the future, but interestingly in mainland Europe outside France the tide is generally turning against very high speed operations, with 250kph or thereabouts being settled on as a reasonable cost/benefit compromise, in Germany for instance using their new ICE4s. These very lightweight trains have excellent acceleration performance, which helps make up for their lower top speed, and high energy efficiency. Their manufacturers have also managed to squeeze power bogies beneath a 760mm floor height, which ensures level boarding at TSI standard platforms is possible.

 

[MarkyT]

My guess: it maximised interior space available to passengers, providers a more quiet ambiance due to no traction equipment being under the coaches, and it makes maintenance easier as power cars can be swapped around without having to take the entire set out of service

Not such a big issue with electric (only) rolling stock though. For the first time, I sampled the new GWR cl. 800 a few weeks ago between Bristol and Didcot. Going one way I was seated in a driving trailer, without any motors or diesels underneath, and I found the ride rather poor, especially at speed clattering through junctions. Later in the day I returned in one of the powered centre cars where by complete contrast the ride was as smooth as I'd ever experienced in any train ever in the UK. Importantly I could feel no vibration nor hear any noise at all from the diesel.

 

[MarcVD]

SNCF sticks to end power units for good reasons, in my opinion.
First of all, as far as I know, there is no double decker with distributed traction unit capable of 320 km on the market today.
And whether this is feasable while keeping the weight per axle below 17 tons remains to be proven.
Second, this is more flexible. SNCF plays with exchanging power units to better follow the market needs, and it works.
Why should they change a winning team ?

 

[jopsuk]

we really need a split in this thread.

There's been basically three true double deck High Speed trains:
TGV Duplex (across several generations)
JR East E1 Series
JR East E4 Series

The latter two are 240km/h max compared to the 320km/h of the Duplex. The Shinkansen are a little bit taller and benefit from a more square loading gauge but I think it's telling that none of the Japanese conglomerates have come up with a 300km/h+ double decker, and JR East are even withdrawing the E4 despite the last of them being delivered in 2003- they clearly see the future in faster single deck trains and the railway culture there has always been about EMUs on the Shinkansen

SNCF clearly has no cultural objection to EMUs but I'm guessing that attempts by Alstom to fit the traction gear into a double decker EMU resulted in too great a loss in seating, hence the consolidation into "compact" power cars?

So far only Morocco's ONCF has bought any sort of TGV Duplex outside of France though

 

[MarkyT]

... JR East are even withdrawing the E4 despite the last of them being delivered in 2003- they clearly see the future in faster single deck trains and the railway culture there has always been about EMUs on the Shinkansen

I read that it is the collapse of the mass long distance commuting market into Tokyo that has led to double deck stock being abandoned, coupled with the desire for higher speeds. The demand for such heroic commuting was driven by Tokyo's stratospheric property prices which have stabilised or fallen in recent decades allowing many more people to live closer to their places of employment. Interesting too that in Japan there are a few double deckers even on the narrow gauge (with its very British like loading gauge). There were a number of long distance sleeper trains with two levels, but these have largely been withdrawn now following recent Shinkansen extensions although some of the stock may have been recycled into luxury cruise trains I believe. Some shorter express suburban routes around Tokyo feature a small number of bilevel cars for 'green' class only which is the Japaneses equivalent of first class. It's possible that the lower density in the premium accommodation makes bi-level feasible because total capacity on both levels is approximately equal to a standard class singe deck car on the same train, so loading speed through standard size doors is similar.

 

[43096]

That’s SNCF really wanting to stick with end power units.
That’s why it’s not an AGV, as the AGV has distributed power.

Does a double-deck AGV design exist? One reason retaining the power cars might be that fitting power equipment for 9MW of output in double deck cars may be difficult without losing too much space.

 

[MarcVD]

No there is no double deck AGV... As you say, finding space for traction equipment in a car body with two levels would not be easy, as well as keeping up with the 17 tons axle load limit.

 

[MarkyT]

Does a double-deck AGV design exist? One reason retaining the power cars might be that fitting power equipment for 9MW of output in double deck cars may be difficult without losing too much space.

The most recent series of French record breaking runs took place in 2007, where a speed of 554.3 km/h was achieved using a specially modified short TGV train incorporating three duplex coaches sandwiched between two power cars. To boost the total power available, the bi-level coaches were specially fitted with additional power bogies in the manner of AGV trains:
https://en.wikipedia.org/wiki/TGV_world_speed_record#Record_of_2007
This suggests that a complete duplex AGV might be feasible, but some space needs to be found for the traction control equipment, main transformers, pantograph wells etc. For the special runs all this was in the end power cars, but with a fully distributed drive train load space within the passenger cars would have to be sacrificed.

 

[AlexNL]

Does a double-deck AGV design exist?

Maybe some vague sketches or rough designs linger around in the Alstom offices, but they for sure have never built one.

The AGV has been a project years in the making (it was first mentioned in 1998!) which Alstom paid for out of their own pocket. There were no customers who were looking for an AGV until NTV (finally) placed an order for 25 of them in 2008.

This was the only order Alstom ever got for that product: SNCF was only interested in getting more TGV Duplex trains, while Siemens and Bombardier managed to win orders for their Velaro and Zefiro platforms throughout the world. Coming up with a full design for an "AGV Duplex" would have cost Alstom even more money, and would likely have produced little to no result.

A similar trend can be seen with the Prima 2 locomotive: the only customer Alstom ever got for that were Moroccan railways ONCF, who bought 20 of them (and ordered 30 more this year). While Alstom have managed to sell 800 Prima 2-derived locomotives to Indian Railways, the Prima 2 never managed to make a dent in the Vectron/Traxx duopoly.

 

[CMS]

You'll have to take my word for it as I cannot find any online sources, but I'm pretty sure there is a maximum 1000 people per train limit on any train using the concession as this is the maximum number of people manageable for the relevant authorities at a given time in an evacuation of one given train. This would seem to be why Eurostar e320's 900 seats + crew is just about ok. A TGV Duplex is 510 seats, so a UM is a definite no - you might as well use an e320.

If TGV Duplex stock did run on the line, or be acquired by Eurostar, that would pretty much be it for Ashford International as I don't think they would get through the junctions there. Given the e320 problems with Ashford too, it could just be the final nail in the coffin.

From personal experience though, the TGV Duplexs which have been OUIGO'd have been done so very well and are very, very well loaded. I once joined a OUIGO with 1224 passengers according to the train crew! This makes me question if the OUIGO model is exactly applicable to HS1, as even if the 1000 people rule I have mentioned is untrue/removed, only St Pancras has the capacity to process 1224 passengers per train and it's at breaking point with Eurostar alone. I doubt Stratford would have the space.

 

[jopsuk]

I know we're wandering a little off topic, but one issue with the occasionally floated "use stratford as a budget/ouigo-style terminal" is that the track layout is a bit rubbish for that- trains would need to run empty into St Pancras and reverse there*. It wasn't planned for it to be used in that way, it was supposed to be a London stop for North of London services. Wha it really needed for this to be viable (never mind the political situation and the technical requirements) was a reversing siding between the tracks to the west of the station, accessible from all platforms (and from the depot)

*Or: A- run into the Up tunnel towards St Pancras, stop, reverse up the depot road, stop, reverse again back down into the down tunnel, stop, reverse into the Departure platform or B: reverse in the Up tunnel , head back through either on the through line and the crossover onto the domestic platform loop and thence through the crossover to the down line, stop in the tunnel, reverse into the Departure platform. Both of these seem like terrible ideas.

 

[edwin_m]

Couldn't they run empty most of the way to St Pancras and then reverse on the WCML connection? i don't think it's used except by night-time freight.