The Mountaineer was a summer-only passenger train connecting Boston with Littleton, running via Dover, North Conway and Crawford Notch.

Like most summer trains, it was suspended during World War II, but resumed service in August 1945 and operated until 1961.

By 1946, the train's popularity outstripped the Yankee's seating capacity and it was replaced with deluxe coaches, a parlor-diner car and a diesel locomotive.

[3] Budd Rail Diesel Car’s replaced the locomotive-hauled train in 1953 and daily service resumed.

For the summer of 1956, the terminus was moved from Littleton to Intervale, eliminating the scenic run through Crawford Notch and ending service to the Mount Washington Hotel.