Amtrak is celebrating the start of fall with a Northeast flash sale that has big savings on popular routes.

The rail company is offering 25 percent off select routes when travelers book by Oct. 5 and travel on Mondays, Tuesdays, and Wednesdays from Oct. 7 to Dec. 18, according to the company. The discount is valid on the regular-priced flex fare rate.

“With our Northeast Fall Flash Sale, guests can experience the convenience of Amtrak at a great value,” Eliot Hamlisch, Amtrak’s executive vice president and chief commercial officer, said in a statement. “With these discounts, it’s a perfect reason for travelers to escape for a fall getaway, see breathtaking views of vibrant fall foliage, or snap up tickets for holiday travel early.”

With the sale, travelers can zip between Boston and Washington, D.C. with many popular options to stop in between. Travel from Boston to Providence starting at just $16 each way in coach or starting at just $62 each way in business class, or travel from Philadelphia to New York City starting as low as $26 each way.

Travelers can also head from New York City all the way to Boston or from Washington D.C. to the Big Apple starting as low as $42 each way.

The promotional fares are available in both coach and the company’s Acela Business class, but upgrades are not permitted. The sale is also not available during blackout dates from Nov. 25 to Dec. 2.

The promotion is valid on any trains except the Crescent, Cardinal, and Silver Service lines.

The Northeast fall sale comes ahead of Amtrak’s plans to create a brand-new route, the Floridian line, temporarily combining the Capitol Limited and Silver Star lines. The new route will run from Chicago all the way down to Miami and comes ahead of the East River Tunnel Rehabilitation Project in New York, which will close one tunnel tube at a time.