The Bangor and Aroostook Railroad (reporting markBAR) was a United Statesrailroad company that brought rail service to Aroostook County in northern Maine. Brightly painted BAR box cars attracted national attention in the 1950s. First-generation diesel locomotives operated on BAR until they were museum pieces. The economic downturn of the 1980s coupled with the departure of heavy industry from northern Maine forced the railroad to seek a buyer and end operations in 2003.
BAR began hauling potatoes in heated box cars in 1895. Potatoes provided a stable income source through the great depression, and provided 50% of the railroad's revenue following World War II. BAR had the 2nd largest United States railroad-owned reefer fleet (after Santa Fe) during the 1950s. BAR made an arrangement with Pacific Fruit Express whereby PFE reefers shipped Maine potatoes during winter months and BAR reefers carried California produce during the summer and autumn. While potatoes started moving by truck following completion of the Interstate Highway System into northern Maine in the 1960s, what actually resulted in the railroad losing its potato business forever was the Penn Central Transportation Company (PC), whose interchange service became so bad during the winter of 1969–70 that a large portion of the 1969 potato crop was spoiled by freezing when car heaters ran out of fuel. The claims process against PC was not resolved prior to PC's bankruptcy declaration the following June. As a result, several potato farms went out of business; and those that survived distrusted rail service and never returned to using the railroad.
Inbound chemicals and outbound paper from mills on the Penobscot River at Millinocket and East Millinocket were major revenue sources for the BAR from 1900. Another paper mill was built in Madawaska in 1925. Pulpwood and wood chips to the paper mills became increasingly important as potato loadings declined. The remote port facilities at Searsport were a preferred loading point for ammunition during World War II; and BAR transported heating coal and aircraft fuel to Loring AFB for Strategic Air Commandbombers through the Cold War. BAR painted 2,500 box cars in the red, white and blue colors of the US flag during the 1950s. A less expensive oxide red paint scheme with large white reporting marks was adopted during the Vietnam War.
The Bangor and Aroostook rostered some 150 different steam locomotives over its history. Most were built by the Manchester Locomotive Works or the American Locomotive Company (ALCO), which absorbed Manchester in 1901. The most popular type was the 4-6-0, with nearly 60. Diesels began arriving in the late 1940s; general purpose types such as the EMD GP7 and EMD GP38 were common. Unusually, the BAR also rostered eight EMD BL2 "branch line" locomotives, precursors to EMD's GPs. Many first-generation diesels remained in operation on the BAR until they were museum pieces. In the 1950s its red, white, and blue boxcars attracted national attention.