Onboard WiFi on NEC regional trains seems to be getting worse every time I ride. The problem is there simply isn't enough band width on board to provide 400 or so passengers with anything resembling 'reasonable' service, mostly between WAS and NYP. What seems to happen is that although I've successfully 'connected' to the WiFi, unless the Amtrak 'Agree/Greeting' screen comes up on its own, going directly to any website will fail. I used to be able to go to that screen myself (I saved it as a bookmark) but even that doesn't work any more. And should you 'wait it out', internet response times are worse than dismal...minutes some times.
On the other hand, Wifi on the Acela works far better all the time. A quick check with my Wifi 'checker' app reveals considerably more available WiFi channels than on the regional trains.
These days, I've routinely switched to using my cellphone connected via USB to my laptop between WAS and NYP. Problem solved. NYP-NHV is usually OK, but sometimes slow. Too often, WiFi on the 2-car shuttle trains NHV-SPG doesn't connect to the internet. Cellphone to the rescue.