Acela150
Super Buff
Effort will be made to try to keep the Acela trainsets oriented the same with Car 1 on the South/West end closest to Washington and Car 6 on the North/East end closest to Boston ergo on an odd numbered train the first class *should* be at the front and on an even numbered train first class will *should* be at the rear.
They've done a fairly good job at it recently and before the Covid-19 crisis at least from what I've seen.