I finally had a chance to ride the new NextGen Acela and I have to admit, I was wrong: this really is Amtrak’s train of the future. What’s a NextGen Acela? Reserved seats: Seats on all Acelas are now reserved. Boarding advice: The cars on the NextGen Acela are much shorter than the regular trains, so position yourself carefully on the platform to minimize walking once the train arrives. The food cart on the NextGen Acela train.