Abilene & Southern 2-8-2 "Mikado" Locomotives in the USA

Class Details by Steve Llanso of Sweat House Media

Class 20 (Locobase 16156)

Data from T&P 1 - 1951ca Locomotive Diagrams Combined supplied in May 2005 by Allen Stanley from his extensive Rail Data Exchange. Works number was 67102 in September 1926.

One of only two locomotives purchased new by the A&S, this small Mikado had generous amounts of heating surface area, 11" (279 mm) piston valves to admit the dry steam into the cylinders, and low drivers to generate good starting tractive effort.

The 20 enjoyed a long career. It put in almost 25 years of steady service on the A&S. In 1950, that railroad converted to diesel power and the 20 moved over to the Texas & Pacific, which operated it out of Alexandria, La until its retirement in February 1953. The Louisiana Eastern bought the 20 in October 1953 and renumbered it three times (5, 13, and 11) before its scrapping in 1962.

Principal Dimensions by Steve Llanso of Sweat House Media
Locobase ID16,156
RailroadAbilene & Southern
Number in Class1
Road Numbers20
Number Built1
Valve GearWalschaert
Locomotive Length and Weight
Driver Wheelbase (ft / m)15 / 4.57
Engine Wheelbase (ft / m)31.08 / 9.47
Ratio of driving wheelbase to overall engine wheebase 0.48
Overall Wheelbase (engine & tender) (ft / m)60.08 / 18.31
Axle Loading (Maximum Weight per Axle) (lbs / kg)
Weight on Drivers (lbs / kg)135,000 / 61,235
Engine Weight (lbs / kg)175,000 / 79,379
Tender Loaded Weight (lbs / kg)124,521 / 56,482
Total Engine and Tender Weight (lbs / kg)299,521 / 135,861
Tender Water Capacity (gals / ML)6000 / 22.73
Tender Fuel Capacity (oil/coal) (gals/tons / ML/MT)2584 / 9.80
Minimum weight of rail (calculated) (lb/yd / kg/m)56 / 28
Geometry Relating to Tractive Effort
Driver Diameter (in / mm)56 / 1422
Boiler Pressure (psi / kPa)200 / 13.80
High Pressure Cylinders (dia x stroke) (in / mm)20" x 28" / 508x711
Tractive Effort (lbs / kg)34,000 / 15422.16
Factor of Adhesion (Weight on Drivers/Tractive Effort) 3.97
Heating Ability
Firebox Area (sq ft / m2)141 / 13.10
Grate Area (sq ft / m2)41.50 / 3.86
Evaporative Heating Surface (sq ft / m2)2166 / 201.23
Superheating Surface (sq ft / m2)551 / 51.19
Combined Heating Surface (sq ft / m2)2717 / 252.42
Evaporative Heating Surface/Cylinder Volume212.75
Computations Relating to Power Output (More Information)
Robert LeMassena's Power Computation8300
Same as above plus superheater percentage9960
Same as above but substitute firebox area for grate area33,840
Power L114,356
Power MT937.76

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