As a former Amtrak rider during my college years in the 80's in the Northeast Corridor (BOS/PVD-Stamford, CT), I see that NOTHING has changed! If I just had a one hour delay, I considered myself lucky.
As a previous poster mentioned, AMTRAK does not own the tracks. AMTRAK trains have the lowest priority. The track owners let their own freight and commuter trains go by and shuffle AMTRAK off on a side track for 30 minutes. I had it happen a number of times in the NE (the "best" part of the country for riding trains).
One time a commuter train caught on fire in the Stamford station and the stupid Conrail people wouldn't tell the AMTRAK people what was going on. I actually overheard the conversations and, trust me, it wasn't pretty. Meanwhile, we sat just outside the station for 90 minutes. In retrospect, I'm lucky my relatives just didn't give up and go home!