I really do not see a lot of difference in the crews as between one train and another. I think it is sort of chance the way we encounter that.ALso, of course, particular individuals can be much nicer(or much worse) than average.
Until I took a very long trip around the country two years ago, I had the following pet theory. I thought that on the whole the sleeping car crews on really long distance trains were better than those on shorter hops. I felt I had observed a pattern going on that. But then I reasoned it might be that we simply have more time to get acquainted with the crew on a long trip. On an overnight haul, say from ATL to DC, very little interchange is usually needed with the crew, even with the sleeping carattendant.
BUt I have left my point---that trip two years ago(ATl-NO-LA-=SF-CHi-BOS-NYC-ATL- almost all of the sleeping car attendants left a LOT to be desired. I enjoyed the trains but was pretty sickened by many of the crew....blew my theory to hell about long distance crews being nicer, or at least us getting to know them better.
Prior to Amtrak, the only railroad which stood out for me as being especially rude---and I don't want ot step on anybody's toe's here---was the Seaboard. And it advertised itself as the route of courteous service.I had a couple of bad encounters and witnessed some other bad encounters happening to other passengers. Other acts of rudeness through the years seemed to come more from specific individuals, not an entire train crew. Though maybe sometime an entire dining car crew, working together, can be very good or very bad, true......but you will can make a return trip on the same train and find just the opposite.