In preparation for what it expects to be the busiest Thanksgiving holiday ever, Amtrak announced Wednesday that it will add 75,000 seats next week, increasing service nationwide by 15 percent.

On the Northeast Corridor between Washington, D.C., and Boston, Amtrak will operate some all-reserved trains to increase passengers’ chances of getting a seat. Passengers with general tickets who do not have reservations will not be able to board these trains.

Since the terrorist attacks on Sept. 11, Amtrak said it has experienced daily sold-out conditions on its new high-speed Acela Express services on the East Coast, as well as Metroliner service between Washington and New York.

Due to heightened security measures, passengers boarding at any station between Washington and Boston must now purchase tickets before boarding their trains. Passengers are required to present photo identification, such as a driver’s license or passport, to purchase tickets or check baggage.

Last Thanksgiving, Amtrak said it carried 567,000 passengers nationally.

–Yale Daily News