[CaptainZapp]

Just to put that in perspective :

Shinjuku station in Tokyo (the world's busiest train station by passenger count) serves 3.64 million passengers per day.

https://en.wikipedia.org/wiki/Shinjuku_Station

[dionidium]

Your numbers for that station include inter-city rail, commuter rail, and subway lines. My numbers were only for Amtrak (inter-city rail). If everything is included, then Penn Station serves about 600k passengers per day.