I stand corrected. I wonder how often?
However, when one has a kid, the flight from Washington to NYC is faster, and AMTRACK is almost as expensive...so the "poor" way to travel is to take a bus, which takes forever, and would not be cost effective.
Actually, Amtrak is much cheaper and just as fast, door to door. There have been plenty of "races" to show this. The people on the Shuttle going DC to NY are people who think they need to look important. The people concerned about money (the large majority of ordinary travellers and businesmen) ride on Amtrak.