Alstom’s TGV Duplex is an articulated trainset, there are Jacobs bogies in-between the cars.

The Talgo 21 DMU/22EMU are also articulated bi-level trainsets. The Spanish company’s patented wheelset, passive steering and passive tilt technologies are all included. With each wheel on its own axle, designers were able to create aisles that run the length of the train on both levels. The individual cars are very short (~8m = 25ft) but wide enough to seat five abreast. However, this particular product is aimed at the regional rail market so top speed are 140-200km/h (90-125mph). No word yet on when/if the company intends to apply this innovative bi-level concept to the HSR market, where it currently offers the single-level Talgo 350.

TGVs do not meet federal standards for running on shared rail systems with freight trains (meeting those standards would cause the TGVs to be much heaver so they wouldn’t be able to go as fast - that’s one of the problems with Amtrak’s Acela). This is also why CA is having to build all new dedicated tracks for their high speed rail. Unless the standards for passenger only trains gets changed, the dedicated tracks situation will have to remain.

The interior of the trains are a bit cramped compared to some of their bi-level European counterparts, but are plenty comfortable. The absurdly huge Amtrak Superliners cannot fit through any of the NYC tunnels, and are (as far as I’m aware) taller than any other rolling stock in widespread use around the world. The loading gauge of the American rail system is generally quite a bit larger than what is seen in Europe.

Articulated bi-level coaches would be a particularly neat trick, and would likely increase capacity even further. Amtrak could possibly even run bi-level TGVs on the northeast corridor without extensive modification if they’re allowed to use NJTransit’s new tunnel. Why they didn’t do this to begin with boggles my mind… (European rolling stock also tends to offer much greater ride comfort than what’s available in the US, with the new NJTransit coaches coming immediately to mind)

Your assertion is to general to be accurate: a double decker can be as fast as or faster than single decker. You should read the wiki about the TGV Duplex, it’s very informative and exact. Because of the very special train structure (articulated train with bogies in between the cars) and very strict requirement of a 17-ton axle load limit, a Duplex weights the same than a TGV Réseau. The train set can reach speeds of 320kph and develops 23kW/t… This power to weight ratio is the real meter for any speed related issue.

All the figures given for an emtpy train set.

First TGVs (Sud-Est) - 16.7kW/t (weights 385 t)
ETR 500 - 14.72kW/t (598 t)
Eurostar (London-Paris) - 15.00kW/t

all similar, and by comparison;

TGV Duplex - 23kW/t (380 t)
Series 500 Japan - 28.9kW/t
ICE 3 - 19.5kW/t (409 t)
Velaro E - 20.7kW/t
AGV - 22kW/t

I think you’re mistaken about the single deck trains being faster, the record setting TGV was a double deck train.

Andrew in Ezo is right about using double deck on the at-capacity lines: The TGV Duplex was first used on the Sud-Est line from Paris to Lyon, which has always been the busiest line.

The same system can be designed for the Acela and Cal-HSR (if they haven’t already thought of it) if it was needed without problems.

We already have a bunch of double-decker trains in New Jersey, Long Island, California, and Chicago. Unfortunately the double-deckers cannot be used on the busiest (and oldest) areas of the American system (Hudson River tunnels and East River tunnels to Penn Station, entire New Haven Line) because of clearance problems with tunnels, bridges, and catenary wires.

I do wonder if the California HSR program and other potential HSR networks throughout the country have studied the feasibility of double decker trains in their construction plans.

When it comes to Acela, Congress and the FRA get the black eye. The designers had virtually nothing to work with. Its a feat that Acela gets up to 150 mph, considering it is designed like a freight train to withstand a wreck with a freight train because tracks are shared and god forbid anybody using 21st century train control and signaling systems.

The whole rail industry over here needs a colossal make over. They need a definitive plan of action and it needs to be executed. Its really that simple. If Congress doesn’t have a clue, well the rest of the world does, ask them to do it, they will be more than happy too.

Look at the plan SNCF has for the US HSR systems. Now there’s something, the Company that has run the TGV for 30 years and made it profitable wants to come here and do the same thing here….Oh but wait its FRENCH and EUROPEAN and they’re SOCIALIST. I had this argument this weekend and those were the reasons I was given as to why its a bad idea, nothing else just those three things.

Alstom has hinted that a duplex AGV is on the way, but they haven’t released any details or timelines.

Not entirely true. Several of the American “Flyer” series of lightweight trains used Jacobs bogies. But most had been retired by the time the TGV was developed, and Budd certainly wasn’t making new ones.

While the Acela train order left a sour taste, I wonder if it’s Alstom or Bombardier who gets the black eye for that? Conversations I’ve had suggest it’s Bombardier who’s reputation got damaged. (And some versions of the story suggest the problems came from Amtrak.) Of course reputation and truth are not necessarily the same thing.