#1365 is one of forty S-4 class Vauclain compound Ten Wheeler (4-6-0) type locomotives built for the Northern Pacific in 1902 by Burnham, Williams & Co., an early incarnation of the Baldwin Locomotive Works. As built, it had 15½" x 30" high pressure and 26" x 30" low pressure cylinders (few Vauclains had such a long stroke).
#1365 was first assigned to haul the Northern Pacific's prestige passenger service, the North Coast Limited, between Missoula, MT, and Spokane, WA. The assignment was shortlived, however, as NP’s Q class Pacifics (4-6-2) soon took over. It was then reassigned to branchline freight, mixed and passenger service.
By this time, compounding, other than in Mallets, was falling out of favour amongst US railroads. The main advantage was claimed to be lower fuel and water consumption, but the arrangements were mechanically complex, Vauclains produced uneven forces and excess wear at the crosshead, and increased maintenance costs largely offset any fuel economies. The S-4s were consequently superheated and simpled with 21" x 30" cylinders at NP's South Tacoma Shops in 1917.
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After the rebuild, #1365 weighed 184,850 lbs, 146,000 lbs on its 63” drivers. The engine wheelbase is 26’ 5” and the driver wheelbase 14’ 10”. It has a 49.7 sq ft grate, 155 sq ft firebox, including 28.46 sq ft of arch tubes, and total heating surface of 2,732 sq ft, including 485 sq ft superheating. Operating at a boiler pressure of 200 psi, it delivered 35,700 lbs tractive effort, close to 25% more than as a saturated compound.
Right, the engine has inside Stephenson valve gear and steam chests.
After completing its last run on 16th June 1954 helping the Mainstreeter over Evaro Mountain, #1365 had run over a million miles in service, working every branch line on the Rocky Mountain Division.
Slated for the torch and actually moved to South Tacoma for disposal, the locomotive was rescued by the determined efforts of enthusiasts like the photographer Ron V. Nixon and the interest of Northern Pacific Director Walter H. McLeod amongst others. #1365 was cosmetically restored and moved to Missoula and dedicated at its current site on 10th November 1955.