Proper noun
(US, rail transport) The service mark of Amtrak's high-speed rail service in the Northeast Corridor of the United States.
(US, by extension) The Northeastern United States, generally north and east of Washington, D.C..
Source: en.wiktionary.orgAmtrak first offered free Wi-Fi service to passengers aboard the Downeaster in 2008, the Acela Express and the "Regionals" on the NEC in 2010, and the Amtrak Cascades in 2011. Source: Internet
Northeast Regional and Acela lines will still operate between Boston, New York, and D.C., but with some reductions in frequencies for certain markets. Source: Internet
Frequent service will be available on Acela and Northeast Regional trains between Boston, New York, Washington, and Virginia. Source: Internet
Last October, the Northeast US was plastered with ads for something called Acela, a new express train running from Boston to Washington. Source: Internet