These Mikados had 12" (305 mm) diameter piston valves.
Rail weight was 75 lb/yard (37.5 kg/metre), grades sloped gently up 1%, and radii of 461 feet (140.5 metres).
All saw out steam on the L&A. 553-554 were scrapped in March 1952 while the others were broken up in July 1953.
The indefatigable Stanley later (February 2006) unearthed another diagram book that had slightly more legible numbers, which allowed Locobase to estimate most of the missing numbers. As it happens, the L & A, like some other railroads, did not record the superheater area separately. Locobase's estimate for the area is based on 5 other Mikados with identical numbers of flues of nearly identical lengths, properly interpolated.
Note the hefty booster engine - 16,500 lb tractive effort is among the highest Locobase has recorded. Few North American Mikes had cylinders as small as 23" in diameter.
|Specifications by Steve Llanso of Sweat House Media|
|Railroad||Louisiana & Arkansas||Louisiana & Arkansas|
|Number in Class||6||5|
|Locomotive Length and Weight|
|Driver Wheelbase (ft / m)||16 / 4.88||17.25 / 5.26|
|Engine Wheelbase (ft / m)||35.33 / 10.77||36.92 / 11.25|
|Ratio of driving wheelbase to overall engine wheebase||0.45||0.47|
|Overall Wheelbase (engine & tender) (ft / m)||70.83 / 21.59|
|Axle Loading (Maximum Weight per Axle) (lbs / kg)|
|Weight on Drivers (lbs / kg)||184,000 / 83,461||208,000 / 94,347|
|Engine Weight (lbs / kg)||259,000 / 117,481||282,000 / 127,913|
|Tender Loaded Weight (lbs / kg)||220,000 / 99,790||220,000 / 99,790|
|Total Engine and Tender Weight (lbs / kg)||479,000 / 217,271||502,000 / 227,703|
|Tender Water Capacity (gals / ML)||8000 / 30.30||9500 / 35.98|
|Tender Fuel Capacity (oil/coal) (gals/tons / ML/MT)||3806 / 14.40||4000 / 15.20|
|Minimum weight of rail (calculated) (lb/yd)||77||87|
|Geometry Relating to Tractive Effort|
|Driver Diameter (in / mm)||57 / 1448||63 / 1600|
|Boiler Pressure (psi / kPa)||200 / 13.80||240 / 16.50|
|High Pressure Cylinders (dia x stroke) (in / mm)||24" x 28" / 610x711||23" x 32" / 584x813|
|Tractive Effort (lbs / kg)||48,101 / 21818.27||54,814 / 24863.24|
|Factor of Adhesion (Weight on Drivers/Tractive Effort)||3.83||3.79|
|Firebox Area (sq ft / m2)||210 / 18.87||278 / 25.84|
|Grate Area (sq ft / m2)||57.20 / 5.32||60.10 / 5.59|
|Evaporative Heating Surface (sq ft / m2)||3491 / 323.14||3971 / 369.05|
|Superheating Surface (sq ft / m2)||782 / 73.42||1053 / 97.86|
|Combined Heating Surface (sq ft / m2)||4273 / 396.56||5024 / 466.91|
|Evaporative Heating Surface/Cylinder Volume||238.12||258.06|
|Computations Relating to Power Output (More Information)|
|Robert LeMassena's Power Computation||11,440||14,424|
|Same as above plus superheater percentage||13,499||17,453|
|Same as above but substitute firebox area for grate area||49,560||80,731|