However, that doesn't stop people from arriving. Eventually, the stations fill up and policemen start to appear. Eventually, the crowding will create a safety hazard and they'll close the station to new arrivals. Avoid the crowds. Penn Station is like a big assembly line.
Earlier events influence later events.
If you can leave work earlier than usual, do it. The main terminal fills up first, where the waiting room is. Also popular is that area just in front of Kmart. Ignore both of them. This is an ideal spot.