Interesting. Other Youtubes that pop up around the one in the Trains article show the cars testing on the San Joaquin line in California. My first impression: they look like slightly updated versions of the Horizon cars that were used on the SJ's about the time I moved to Fresno (many years ago). Hope they don't meet the same fate; the first set of Horizon cars to go into service there was largely destroyed in a fiery grade crossing crash, in the fog, near Stockton, shortly afterward.

And the paint job ... the Amtrak cars don't look bad, but the California cars look like somebody borrowed a few from Brightline. It's also painfully obvious in the lighting of the videos that the logo in the top panel is a vinyl stick-on; that won't age well in SJ Valley heat or Illinois/Michigan winters.