The east coast trains generally keep good time: it's the transcontinental trains that tend to be very late. When I took the Empire Builder a couple of years ago it arrived in Chicago about four hours late (although at one point in the journey we had been six hours down). The greatest delay I've ever experienced in the US was on a train from Chicago to San Antonio, which arrived 10 hours late.
Oh, I remember Hornepayne, long long ago, in the 1970s. The eastbound stop then was at about 2 am. The diner, which like the rest of the train had come right through from Vancouver, got a hot box on approach, and was detached in the middle of the night. This involved multiple shunts forward and backward in the absolute pitch dark beyond the handful of lights at the Hornepayne station building, using the 4 x F-unit train locomotives which all seemed to have different lags of responses to the throttle. Everybody was woken up by the jolts and brake applications, culminating in propelling the seating coaches back onto the sleepers at what must have been a good 5-10 mph, which probably threw half the occupants of the latter out of bed. We were hours late, and when the sleep-disturbed passengers got up for a 7 am breakfast they found nothing - no diner, no food.
Halifax and Montréal again.
When I travelled on Empire Builder in 2011 the dining car steward insisted that my travelling companion and I share a table with other passengers, even though the dining car was half empty, and even insisted that we had to sit side-by-side and not facing across the table.
Rock Island's bankruptcy didn't impact their liability to run the passenger services - many US rail companies had been bankrupt, some multiple times, in the 20th century and the liability just carried on (note that in the US bankrupt companies are often able to continue and rebuild). There was a 5 year requirement of service after Amtrak was founded, for those who didn't join at the start, and when this was up the RI passenger services, entirely within Illinois by this time, were supported by the state. They ended about 1979 when the state support money was cancelled. The company, still legally bankrupt, was still operating at this time, it shut down some years afterwards, mainly due to a strike.
Sometimes we wanted to meet and talk to other passengers and sometimes we didn't: I think that's perfectly reasonable on a long train journey. Obviously, at times when the dining car was full we had no problem whatsoever with sharing a table - and yes, as you say, it was often great fun - but there were times when the staff seemed determined to lay and serve as few tables as possible and made everyone sit at one end of a mostly empty car. The tip they got from us reflected their willingness to accommodate our wishes (which is as it should be).
The food was passable, although not nearly as good (or as plentiful) as you would find at a proper diner. Furthermore, some items on the menu were unavailable from the outset and by the end of the journey there was extremely limited choice.
