Missouri-Kansas-Texas 4-4-2 "Atlantic" Locomotives in the USA

Class Details by Steve Llanso of Sweat House Media

Class M/E/I (Locobase 7085)

Data from MKT 1904 Locomotive Diagrams supplied in May 2005 by Allen Stanley from his extensive Rail Data Exchange. See also DeGolyer, Volume 20, p. 37. (Thanks to Chris Hohl for his 9 April 2018 email reporting the correct valve gear and cylinder diameter.) Works numbers were 14346 in July 1895 and 14455-14460 in August.

Pretty unusual Atlantics for the time. Note the small drivers, 50" trailing wheels, a very long, straight boiler with the steam dome over the second driving axle and sand dome just ahead of the first set of drivers. Locobase doesn't know what motivated the MKT to buy these 4-4-2s. The Baldwin spec was quite specific (so to speak) when they noted that the last locomotive would use 19 1/2" (495 mm) cylinders. The larger cans inched the calculated tractive effort to 21,610 lb (9,802 kg or 96.1 kN).

Locobase notes that, whatever the reasons for this Atlantic design, the purchase didn't go to waste. The class gave almost three decades of service before being scrapped in 1923-1924.

Principal Dimensions by Steve Llanso of Sweat House Media
Locobase ID7085
RailroadMissouri-Kansas-Texas (MKT)
Number in Class7
Road Numbers296-302/201-207
Number Built7
BuilderBurnham, Williams & Co
Valve GearStephenson
Locomotive Length and Weight
Driver Wheelbase (ft / m) 6.25 / 1.90
Engine Wheelbase (ft / m)24.17 / 7.37
Ratio of driving wheelbase to overall engine wheebase 0.26
Overall Wheelbase (engine & tender) (ft / m)41.04 / 12.51
Axle Loading (Maximum Weight per Axle) (lbs / kg)
Weight on Drivers (lbs / kg)71,600 / 32,477
Engine Weight (lbs / kg)131,750 / 59,761
Tender Loaded Weight (lbs / kg)95,050 / 43,114
Total Engine and Tender Weight (lbs / kg)226,800 / 102,875
Tender Water Capacity (gals / ML)4300 / 16.29
Tender Fuel Capacity (oil/coal) (gals/tons / ML/MT)9 / 8.20
Minimum weight of rail (calculated) (lb/yd / kg/m)60 / 30
Geometry Relating to Tractive Effort
Driver Diameter (in / mm)70 / 1778
Boiler Pressure (psi / kPa)180 / 12.40
High Pressure Cylinders (dia x stroke) (in / mm)19" x 26" / 483x660
Tractive Effort (lbs / kg)20,515 / 9305.46
Factor of Adhesion (Weight on Drivers/Tractive Effort) 3.49
Heating Ability
Firebox Area (sq ft / m2)147.60 / 13.72
Grate Area (sq ft / m2)28.10 / 2.61
Evaporative Heating Surface (sq ft / m2)1935 / 179.83
Superheating Surface (sq ft / m2)
Combined Heating Surface (sq ft / m2)1935 / 179.83
Evaporative Heating Surface/Cylinder Volume226.79
Computations Relating to Power Output (More Information)
Robert LeMassena's Power Computation5058
Same as above plus superheater percentage5058
Same as above but substitute firebox area for grate area26,568
Power L16579
Power MT405.15

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