It makes more sense if you know that there used to be multiple competing private passenger railroads. Penn Station was the station for the Pennsylvania Railroad. The Pennsylvania Railroad had stops in Newark and in New York. Other railroads had their own stations. Some railroads had shared stations, hence Grand Central, and all of the stations called Union Station.

Of course the PRR hasn't existed in 50 years so maybe it's time to change the name...

> between going to Newark Penn Station or New York Penn Station, which are in opposite directions from the airport.

They're in the same direction from the airport, and the train will stop in Newark Penn on the way to New York Penn. Some people will be confused and try to get off in Newark, although the conductors normally try to announce this really clearly.

Oops, my bad! I was thinking of going from Secaucus station, another big NJ train station, from which they are in opposite directions.

True - it's confusing from there as well!

I’ve seen foreign tourists get off at Newark instead of New York multiple times. I alwaya hoped they figured it out before it’s too late...