Yeah, in the old underground Penn Station it was quite something. It was kind of like the herds of antelopes in the Serengeti. You know, those nature movies where they show the herd milling around, then one of them gets a sniff of a lion or something, and movement ripples through the herd, and very quickly, the herd starts moving very quickly as a mass....They post the track numbers and make the first announcement for boarding simultaneously.
That's was sort of what happened at Penn in the few seconds after the track numbers flipped up on the Solari. Back in the day, the didn't bother with gate ushers, either, the mass of people just headed for the stairs or escalator.
I wonder if animal behaviorists ever went to Penn to study the crowds. It might have made a nice doctoral dissertation, at least.