Thanks for the answers. Maybe I need a trip to NYP to explore more in detail. Anyone have a good map?
I think the more and more I hear issues at other stations, Philadelphia is about the best station out of the top 4 (NYP, WAS, PHL, and CHI).
Website with a handy floor plan for NYP which also shows where the platforms are (eastern end anyway) with respect to the boarding areas above. Shows where the escalators and elevators are, but not a detailed look at where they are on the platforms and how much space is taken up on the platforms by the stairs, elevators, and support pillars.
Of the four stations, PHL is the only one that was not subjected to being rebuilt or having part of its passenger space taken away in the 1960 to 1980s. PHL also has reasonably wide platforms, so there is room for people to wait and board the train after people get off the train. But as jis points out, at PHL they do the single entrance checkpoint/chokepoint for tickets before letting people down the escalator to the platform.