Well, AMTRAK works on the North East Corridor. I can't say about anywhere else in the country.
Being from NJ, replacing the Portal Bridge, and building another rail tunnel across the Hudson (the Gateway Tunnel) is two projects that is well needed. That is a MUST, since it is a major problem that delays the whole line. More freight (which can reduce some truck traffic) into NYC via a second tunnel, and passenger trains (which can reduce car traffic) helps greatly. But we still won't get the very high speed trains between BOS and WAS, that's for sure. The way the Corridor was built historically would not allow it. It's not feasible, and you can only get the over 100 mph speed in certain areas. But Acela is a very nice ride between NYC and Washington. (I've taken it many times) If you want to get there slower, you can take the buses (BOLT, the Hound, etc.). If you need to get there faster, that is why the Shuttle services (AA & DL, and now UA with EWR-DCA) are there for. Plus not only AMTRAK gets that money, services like the METRO (in DC); MARC; SEPTA; NJ Transit; the MTA; and the "T" (in MA) gets some money too, to improve commuter service. That's where the real money is made, (along with the freight service) even though AMTRAK owns the trackage.
If you live in the densely populated Corridor, it is a major win. I agree with eolesen on this.