The Ambassador was a passenger train that traveled from Boston, Massachusetts and New York City, New York to Montreal, Quebec. The train was jointly operated by the Boston and Maine Railroad, the Central Vermont Railroad, and the Canadian National Railway. Beginning service on April 26, 1926, the Ambassador operated on a daytime schedule between Boston and Montreal, with coach, dining, and parlor cars in the consist. There were also through cars to New York City offered until the mid-1950s, split from the Ambassador's consist in White River Junction, Vermont and added to the Connecticut Yankee train for points south.