Make sure that you drop a line to Amtrak each time this happens. Service fails such as plastic aren't the attendants' fault and should not affect their tip. It's also fine for one attendant to take a break (it's 8+ hours WAS-BOS) once the main service is done, but topping up drinks has to be done by the other attendant and, if it gets busy, wakey-wakey.

Amtrak charges a significant premium for F and is cutting back the service. They did this once before (one attendant, no hot meals) during the recession and the result was empty F cars. That's going to happen again. There is a lot of demand for paid F, but people want value too and Acela J is hardly uncomfortable.