The fact they don't mention they are any faster is disappointing. I'm all for a better cabin experience (I take the Acela at least once a month) although first class was perfectly acceptable. Much better than flying.
The new trains can go to 160mph, which is slightly faster than the old ones. But...Acela's speed is really limited by the safety of the tracks not the train sets. I remember when they were testing 155mph service in 2010, but they could only do it on tiny sections of the track. Sadly it only really gets faster once they fix the infrastructure like bridges.
That’s only true with short distances or crappy trains. I’ll drive DC to NYC rather than take the train, as it’s cheaper and not much slower. If Acela were a proper high-speed line I might switch. DC to Boston is close to a toss up, ~7 vs ~9 hours, but a proper high-speed train that did it in 2.5 hours would be really attractive.
With modern high-speed rail and a fairly modest average speed of 200 km/h (taking stops into account, because modern HSR can go >350 km/h), it would only take 3.5 hours to get from DC to Boston (passing through NYC).
I have to drive about an hour in the wrong direction to get to Amtrak from west of Boston. But I hate driving into NYC so I generally do it anyway rather than driving solo even though it takes longer and costs more.