The easiest way to get to DC by train is to take NJ Transit to Trenton, then take Amtrak the rest of the way. Ourbus and Greyhound provide bus service. Google maps has schedule and fare information.
There is 3 trains from new Brunswick to union station in Washington DC. One at 555am, 640am and 120pm. All run by Amtrak. Make reservations ahead of time and price is cheaper.
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