Register by March 14, 2014, for the Go Three, Go Free promotion from Amtrak Guest Rewards.

Take three qualifying roundtrips on Acela through March 14, 2014, and you’ll get one free roundtrip on Acela for use July 1 through Aug. 31, 2014.

There is a minimum spend of $90 per one-way segment for the trips to qualify for the promotion and a limit of two qualifying one-way segments per day.

Free trips are redeemable for Acela business class travel (first class travel for Select Executive members) from July 1, 2014 through Aug. 31, 2014 and are subject to Acela award travel time-of-day restrictions on weekdays.

Standard blackout dates apply: July 3, 2014; July 6, 2014; Aug. 29, 2014.

A maximum of four free one-way trips may be earned.

Visit http://insideflyerus.wpengine.com/link/?10895 to learn more and register for the promotion.