One of the things completely "missed" in this thread is that of motivation.
Back in the "good 'ol days" ...say the 40s & 50s ... The passenger trains were the "shining stars" of the railroads. After all, the Pennsy was "the standard railroad of the world" and had an image to keep. The NYC also wanted to maintain a spotless image, as well.
In short, for the extra fare trains such as the Broadway or the Century, anyone delaying the train for any reason whatsoever was invariably "called on the carpet". In todays terms, they'd hear Donald Trump telling them "You're fired". Delays to other passenger trains also were not tolerated....or, at least, you better have a REAL GOOD excuse to have caused a delay...one they haven't heard before!
Today, there's no motivation whatsoever for the host railroads to get any of Amtraks' trains over the line 'poste haste'. Due to equipment problems, long station dwell times (in my opinion), slow orders, and what not, passenger train operation has been limited to "what is typically doable". In short, if, under "normal" circumstances, it takes Amtrak 18 hours to go from here to there, that's what the schedule will call for. Also, let us not forget rule #2 of railroading...a train cannot leave its' scheduled station ahead of schedule (or is that #3? behind "safety first" and "any train, any track, any direction, any time"?). So, even though circumstances today may allow an early departure, or running faster than the 'scheduled' 50 mph, passenger carriers are required to keep to schedule as much as possible, plus any delays encountered enroute.
Back in the early days of Amtrak, they originally had faster schedules between CHI and NYP/NYC. The problem was the trains were chronically late. Being always late caused a loss of passengers (rough track didn't help, either!). So, better a slow(er) train that is usually on time than a fast(er) train that is always late. That's what the schedules reflect today.
Unfortunately, in the past several years, track maintenance has fallen off, so even the schedules of 5 years ago cannot be reliably maintained. Unfortunately, due to train 'turn' times at endpoints, in many cases, it is impossible to lengthen the schedules any more than they are and still be able to turn the train and get it ready for the return trip 5-8 hours later. As has been seen repeatedly in the past years, especially on the Lakeshore Limited, is that a 5 hour late #49 into CHI becomes a 4-5 hour late #48 departing for NYP. The 'turn' times are already 'tight', and there's no extra equipment available to make an on time departure when the inbound equipment is quite late. I don't know about this winter, but last year Amtrak resorted to anulling a complete round trip of 48/49 to be able to get 'on time' departures when it was running 8-10 hours late each way (or was that 2 yrs ago?)
So, where to from here?
The solution would seem to be more equipment, to be able to make substitute trains that can go out on time as well as to handle maintenance schedules, problems, etc. That requires $$$. Ie, write your representatives and congress people in Washington!