<p>But you want to be sure you get on a train which will stop in New Brunswick. There are various versions of the Northeast Corridor Line, some express various places, end early, etc. There will be a schedule posted, and you can tell which train will stop where. It will probably cost you $13-14 each way. You can buy the tickets in machine (cash or credit card) at the top of the escalator after you get off the last stop of the air train. Then you use the train ticket (hold onto it-it is also what you need to show the conductor!) to get through a turnstile, go to the appropriate track (6 in total I think), go down the stairs/elevator/escalator and wait for your train (there is an air-conditioned waiting room). When you go back to the airport, be sure to keep your train ticket, do not give it to the conductor, you will need it through the turnstile going back to the air train to get to your terminal. It is all self-explanatory once you see it, but I always like to know how it will be…hope it helps.</p>