From Jan. 22 through May 19, members of Amtrak Guest Rewards who take three qualifying roundtrips on Acela Express — the only high-speed train set in the U.S. running between Boston, New York, Philadelphia and Washington, D.C. — will receive a voucher redeemable for one free Acela business class or regional train roundtrip. This “Buy 3 Get 1 Free on Acela” offer is also available if a passenger takes six one-way trips on Acela. There is a minimum spend of $75 per qualifying one-way or $150 per roundtrip and a limit of two qualifying trips per day (roundtrip or two one-way). The free roundtrip voucher is valid for reservations starting Feb. 1 for travel June 1 through Aug. 30, 2007. Members must register for the promotion at http://www.Amtrakguestrewards.com/12207 or call (800) 307-5000 (option 2) using registration code 12207.