Can high speed train sets like TGV or Acela be double headed?
TGV: Yes they are regularly doubled especially between Paris and Lyon. At Lyon they are split / combined for going to the French riveria and toward Spain. All the platforms at stops from Paris to Lyon are long enough to handle 2 - 10 or 11 car sets.
Acela: Yes as I understand it. They were tested before revenue service doubled. However the platform lengths at New York Penn ( NYP) are only capable of 14 conventional car lengths. ( will edit when I check Acela lengths ) Other stations I am not sure (suspect BOS, NH, Baltimore, WASH not long enough ). Another problem may be is the CAT power supply does not have enough capacity to handle 2 double Acelas passing each other?? ( The power problems are being addressed on Amtrak owned NEC completion unknown and also unknown on MNRR ). Amtrak wants to buy 40 Acela cars to lengthen from 7 to 9 cars each train set. If that will occurr in the present political climate is questionable. Also some parts on original Acelas are no longer built. At present there is not enough Acela equipment to double them for trips at present ( only 20 sets with 4 out of service at any time for programmed maintenance ).
Edit: Acela cars are actuall 87 ft long each vs conventional cars 85 ft. So 14 cars would be 28 ft longer + the 2 power cars in middle woould not allow them to fit in NYP. If the Penn station south is ever built that length requirement may be mitigated.
Many pre-Amtrak trains made intermediate stops at stations with platforms shorter than the train’s length. In fact, I believe there were cases where trains were ‘doubled’ at their initial or final terminals. I don’t have documentation of either case but I do have clear memories of long NYC trains making the Albany stop. Passengers simply walked through cars to get to or from the car(s) at the platform.
Can passengers not pass from one car to the next in these trains? Better yet, I believe that all seats are reserved on these trains; can’t the reservations system reserve seats so that they will be in a car or cars that are at the platform?
The “Lake Shore” often makes two stops at Utica - especially if they have both coach and sleeper passengers.
Passenger destination can be an issue eastbound, as the train splits at Rensallear (?) for NYC and Boston. That’s even an issue with checked baggage, as there are two baggage cars on the train through Utica.
Back in PRR days, long trains on what is now called the Northeast Corridor would sometimes make double stops and sometimes just have passengers walk up through the train to get to a car that would make the platform. Have been on trains that made a double stop at Philadelphia and then had passengers walk up at Wilmington. Both methods had their disadvantages and there would usually be somebody who “didn’t get the message” Either way takes time which would work against the “high speed train” idea.
As mentioned above, maybe something could be worked out with the reservation system?
While is Spain a couple of years ago I actually road an Ave train (Spain’s high speed rail service) that consisted of two coupled complete trainsets. No doubt it was part of the service design to deal with peak period loadings. Gives a new meaning to “second section”.