The Atlantic (French: L'Atlantique) was a passenger train operated by Via Rail, serving both Canadian and U.S. territory between Montreal, Quebec, and Halifax, Nova Scotia.

The Atlantic also holds a unique spot in U.S. railroading history as it operated the last regular-service steam-heated passenger train in the United States until Via converted its trainsets to "head end power" in 1993.

Since its cancellation, citizen's groups in southern New Brunswick and the Eastern Townships of Quebec have periodically organized petitions or lobbied to have Via Rail Canada reinstate passenger service to this route.

The service operated overnight using the CPR's former International Railway of Maine line which formed the direct route between Saint John and Montreal.

During this time, Fredericton saw its first passenger trains since the early 1960s when Rail Diesel Cars were instituted from Halifax via Moncton and Saint John to replace the Atlantic's connections.

Southwestern New Brunswickers were incensed at the cutting of the Atlantic's route, one which had seen daily passenger rail service in both directions between Saint John and Montreal since the International Railway of Maine opened in 1889.

Community leaders along the route, led by rookie Saint John mayor Elsie Wayne, quickly rallied local populations to lobby the federal government.

After several years and a personal promise by Brian Mulroney that his government would reinstate Via service on the route, the PC Party won election in 1984 and that December it was announced that the Atlantic would be returning to the rails.

Paul Martin was making aggressive budget cuts throughout the federal government, thus concentrating service on the Ocean's route would likely save some money.

The Atlantic also passed through the only two ridings in the country which elected Progressive Conservatives - Elsie Wayne in Saint John and Jean Charest in Sherbrooke.

Leaving Montreal, the Atlantic followed the route of the Ocean on CN trackage through Saint-Hyacinthe, where it turned south and followed the Saint-François River valley into the Eastern Townships to Sherbrooke where it regained CP tracks.