Update: All good things come to an end, and so it is with this two-day sale. Amtrak is constantly offering deals and promotions, however,  so stay vigilant as you plan your next trip.

Train travelers, rejoice: now's your chance to go from Seattle to Portland for as little as $18 or from New York to Boston for $42. Amtrak has made a number of September routes 50% off, but not for long — you only have until midnight tonight, August 17, to take advantage of these exceptionally low fares.

It isn't just Amtrak regulars who should be excited about this, of course. If you've been meaning to take the scenic route from, say, Chicago to St. Louis ($16) but have never gotten around to it, there's no time like the present; ditto Los Angeles–San Francisco, which can now be done for just $33. Or, for the diehards who don't mind spending nearly 36 hours on a train, Seattle to L.A. is $62 — just make sure you get a seat with an ocean view.

Not every route is heavily discounted, alas: Capitol Corridor, Hiawatha Service, Keystone Service, Pacific Surfliner, and the Pennsylvanian are all excluded from this half-off event. Nearly 40 different routes — with major cities like Chicago, Philadelphia, New York, Washington D.C., and Los Angeles being the most common — could make for great weekend trips, however.

Travel dates must be between September 1 and September 30 of this year, which should be ideal for anyone hoping to escape the summer heat for a bit. Find all the information you need here, and don't forget to act quickly.