Taking a cue from recent airline promotions, Amtrak is offering Buy 3, Ride Free on Acela. 3 roundtrips or even 6 one-ways on the Acela Express by May 19 earns an Acela Business class or Regional Coach class roundtrip.

Registration is required.

And in one of the more annoying clauses I’ve seen (for folks like me looking for every angle), they’ve pretty much ruled out the possibility of doing the promo cheaply or quickly:

Minimum spend of $75 per qualifying trip one-way or $150 per roundtrip. Limit of one qualifying roundtrip or two one-ways per member per day.

Grr.