The Atlantic () was a passenger train operated by Via Rail, serving both Canadian and U.S. territory between Montreal, Quebec and Halifax, Nova Scotia. It was previously operated by Canadian Pacific Railway as The Atlantic Limited between Montreal and Saint John, New Brunswick. It formed part of the transcontinental service for both systems. The Atlantic and its predecessor The Atlantic Limited (along with several other CPR local trains) was the only passenger rail service in the U.S. state of Maine from the late 1960s until discontinuance of operations in December 1994. (Maine is now served by Amtrak's Downeaster.) 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 Atlantic Limited Inaugurated by the Canadian Pacific Railway (CPR) as a "limited stop" service on September 25, 1955, The Atlantic Limited used numbers 41/42 (westbound/eastbound) and took the schedule and equipment for what were previously numbered trains between Montreal, Quebec (Windsor Station) and Saint John, New Brunswick (Union Station). The service operated overnight using the CPR's former International Railway of Maine line which formed the direct route between Saint John and Montreal. Although this was CPR's first named passenger train to the Maritimes, daily passenger service had been offered since 1889. The Atlantic Limited saw the first major change to its route around 1970 when the Saint John Union Station was demolished and CPR's Mill Street yard redeveloped to accommodate the Saint John Throughway and associated urban redevelopment. A new passenger station was built on the city's west side in the former city of Lancaster where new rail yards were developed. During the 1970s, CPR operated the service at minimal levels with usually a single 1800-class E8 locomotive (one of only three, later two, operated in Canada, both by CPR) and a baggage, coach, diner, and sleeper car. Some of the stainless steel Budd Company cars originally ordered for The Canadian also made their way onto this train and there was infrequent availability of a dome car as well. While The Atlantic Limited name was only used officially after 1955 on the Montreal-Saint John