I dislike the term "power car". It's not a car, it's a locomotive. It has a cab, traction motors, machinery to provide power to traction motors, directional orientation, and no prospect of providing any revenue space or passenger services. It can be uncoupled and moved to other trains, albeit by shop forces only.
It reminds me of people trying to act smart by using big or novel words to describe the same thing.
The Brits tried this decades ago when some genius decided the HST 125 (class 43) was actually a train of DMU's that so happened to be 8 intermediate blind trailers bracketed by two single-end-cab-powered cars with no coach seats. Uhhhh noooooooooo... it's two locomotives top-and-tailing eight coaches and a diner.
Amtrak is proud to announce a new train to Florida that doesn't stink: The Floaterian. An all-star just like Babe Ruth.