ba 4-8-2 "Mountain" Locomotives in the USA

The Bangor & Aroostook Railroad took delivery of four "Mountain" locomotives (road numbers 100 through 103) in 1929 and three more (road numbers 104 through 106) in 1930. Three more would follow: two (road numbers 107 & 108) in 1935 and the last one (road number 109) in 1945. All ten of these locomotives were designated Class M and were built by the American Locomotive Company.

The BAR "Mountains" had 22.5 x 30 cylinders, 63" drivers, a 240 psi boiler pressure which resulted in a tractive effort of 50,000 pounds. The weight on the drivers was 214,500 lbs and the total weight for each locomotive was 318,500 lbs. With a full load of 12,000 gallons of water and 18 tons of coal the combined weight of the locomotive and tender was 551,500 pounds.

The BAR also purchased five used "Mountains" from the NYO&W in 1946 and scrapped them by 1949. The ten from ALCO were retired by 1953. There are no survivors.


ClassRoad NumbersYear BuiltBuilder
Specifications for Class M
Wheel Arrangement:4-8-2
Drivers:63" dia.
Weight on Drivers:214,500 lbs
Locomotive Weight:318,500 lbs
Locomotive & Tender Weight:551,500 lbs
Grate Area:65.6 sq ft
Cylinders:(2) 22.5" dia. x 30" stroke
Boiler Pressure:240 psi
Tractive Effort:50,000 lbs
Tender Capacity:12,000 gals. of water
18 tons of coal.
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Wes Barris