They've been running the Siemens Charger locomotives for a little while, and are phasing out the GE Genesis locomotives (which are at end-of-life) as new Chargers are delivered.

The new trainsets are the Siemens Venture cars. Brightline in Florida is already running a version of them - their cars are set up for high platforms only (all their stations have high platforms). The Amtrak cars will work with both high & low platforms, as the older stations on their network still have low platforms (passengers need to step up into the cars)

https://www.trains.com/trn/news-reviews/news-wire/first-look...

I wonder if it's like the double-decker passenger cars used for Metra in Chicago. These trains never change direction (like Amtrak) but just run forward (IIRC) into the city and reverse back out to the suburbs. The car on the end has a small cab where the engineer sits and controls the train when it is running reversed. From the outside the difference between that and a passenger car is pretty subtle.