Ah, how quickly they forget the first time around: AT&T Wireless once installed Wi-Fi at six Amtrak stations across the Northeast Corridor, but I don't believe it worked very well. The manager at Baltimore's Penn Station quoted in this Baltimore Sun article said they'd "experimented with a Wi-Fi connection." Hrmphf. In any case, AT&T Wireless became part of Cingular and now is just AT&T (wireless), and they've shed some of offering along the way.
The new Amtrak station Wi-Fi is run by T-Mobile, which doesn't forget that Wi-Fi is part of its business, and can also be found at the other Penn Station in New York City, 30th Street Station in Philadelphia, Wilmington Station (Delaware), and Union Station (D.C.).
The same station manager might be talking out of turn when he confirms a reporter's question about Wi-Fi on the trains. Amtrak has been rumored in the past to be considering it, but there are few trains in the U.S. that have any form of Internet access on board, and many projects have gone awry in recent months. I expect Amtrak would prefer that they make that sort of announcement directly. There's enough 3G along the Northeast corridor that it's likely a cell-based, somewhat continuous service could be offered with EVDO Rev. A backhauling it.
A typo in the article might reveal the heights to which Wi-Fi hype can climb: an expert consulted estimated "500,000 million" people use Wi-Fi worldwide. Adding the hyphen in makes that statement so much less interesting. But it's also less accurate. Tens of millions of people use Wi-Fi worldwide, not 500,000 to 1,000,000.