Brooks-Scanlon 2-8-2 "Mikado" Locomotives in the USA

Class Details by Steve Llanso of Sweat House Media

Class 4 (Locobase 14691)

Data from Baldwin Locomotive Works Specification for Engines as digitized by the DeGolyer Library of Southern Methodist University, Volume 62, pp. 293, Vol 71, pp. 198+, Vol 73, pp. 393+. Works numbers were 52726 in December 1919, 55399 in May 1922, and 1923, 56290 in March 1923, and 58361-58362 in April 1925.

These logging Mikados burned oil, so they used straight stacks. The superheater dictated the use of piston valves (8"/203 mm diameter). Steep 5% grades prompted a note that the fire box crown was to be arranged for such inclinations.

Only the 4 was delivered with an adhesion weight of 114,000 lb (51,710 kg). All of the others put more weight on the drivers, but 4,800 pounds less (2,177 kg) on the rear truck under the firebox. The difference seems to have originated in an increased amount of water in the boiler. The 4's tender carried the same amount of fuel and water as the later engines, but somehow came in 18,000 lb (8,165 kg) lighter at 70,000 lb (31,752 kg).

A sister to the 6 was sold to the parent's British Columbia operation as their #2; see Locobase 14692.

Georgia-Pacific acquired the 5 in 1956. After its retirement, the engine went on display at Corvallis, Ore. , 7, later renumbered 8, went to the Valley & Siletz as their #56 in 1939.

The #9 later moved to B-S's operations in Foley, Florida. It was then sold to the Albany & Northern in Georgia. After its retirement, the 9 went on display in Camilla, Georgia. It is marked for the Southern and is saluted as the "Spirit of Camilla" on the roof of its display.

Principal Dimensions by Steve Llanso of Sweat House Media
Locobase ID14,691
Number in Class5
Road Numbers4-7, 9
Number Built5
Valve GearWalschaert
Locomotive Length and Weight
Driver Wheelbase (ft / m)12 / 3.66
Engine Wheelbase (ft / m)27.58 / 8.41
Ratio of driving wheelbase to overall engine wheebase 0.44
Overall Wheelbase (engine & tender) (ft / m)50.17 / 15.29
Axle Loading (Maximum Weight per Axle) (lbs / kg)
Weight on Drivers (lbs / kg)118,100 / 53,569
Engine Weight (lbs / kg)144,000 / 65,317
Tender Loaded Weight (lbs / kg)88,000 / 39,916
Total Engine and Tender Weight (lbs / kg)232,000 / 105,233
Tender Water Capacity (gals / ML)4000 / 15.15
Tender Fuel Capacity (oil/coal) (gals/tons / ML/MT)2000 / 7.60
Minimum weight of rail (calculated) (lb/yd / kg/m)49 / 24.50
Geometry Relating to Tractive Effort
Driver Diameter (in / mm)44 / 1118
Boiler Pressure (psi / kPa)190 / 13.10
High Pressure Cylinders (dia x stroke) (in / mm)18" x 24" / 457x610
Tractive Effort (lbs / kg)28,541 / 12946.00
Factor of Adhesion (Weight on Drivers/Tractive Effort) 4.14
Heating Ability
Firebox Area (sq ft / m2)141 / 13.10
Grate Area (sq ft / m2)25.50 / 2.37
Evaporative Heating Surface (sq ft / m2)1576 / 146.41
Superheating Surface (sq ft / m2)328 / 30.47
Combined Heating Surface (sq ft / m2)1904 / 176.88
Evaporative Heating Surface/Cylinder Volume222.96
Computations Relating to Power Output (More Information)
Robert LeMassena's Power Computation4845
Same as above plus superheater percentage5669
Same as above but substitute firebox area for grate area31,344
Power L110,315
Power MT770.22

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Wes Barris