Lehigh & Hudson River 2-8-2 "Mikado" Locomotives in the USA


Class Details by Steve Llanso of Sweat House Media

Class 70 (Locobase 14531)

Data from DeGolyer, Volume 55, pp. 13+. Works numbers were 43062-43063, 43079-43080 in March 1916.

Bearing a 9 1/2-foot (2.896 m) wide Wootten firebox, the 70s were nevertheless conventional-cab locomotives. The Mikado wheel arrangement doubtless simplified the arrangement of crew around the big furnace. The fuel was two-thirds buckwheat coal and one-third bituminous.

The L&HR didn't invest much in 2-8-2s, taking delivery in 1918 of five USRA Light Mikados described in Locobase 16581. The two classes compared very closely in most respects, which helps to highlight how different the conventional firebox of the USRA design was in grate area than these classic culm burners.


Class 80 (USRA) (Locobase 16581)

Data from American Locomotive Company, Standardized Locomotives, US Railroad Administration (Alco Pamphlet 10049, 1918), pp. 16-17, reprinted by (Ocean, NJ: Specialty Press , 1973) and DeGolyer, Volume 58, pp. 61+.

See also "Standard Equipment Specialties," Railway Mechanical Engineer, Volume 93, No 3 (March 1919), pp. 137-138 for a list of all the "special equipment" by manufacturers--everything from air brakes to lubricators to rolled steel wheels--and the USRA designs on which they appeared. (Thanks to Chuck Zeiler for his 26 January 2023 email correcting the Baldwin works numbers.) Works numbers were 49616-49618, 49678 in August 1918

625 engines were built to this basic, and very successful design in 1918-1919, but the L&HR took only four. Compared to the 1916 70 class described in Locobase 14531, these were lighter and smaller in heating surface areas and grate area.

Principal Dimensions by Steve Llanso of Middle Run Media
Class7080 (USRA)
Locobase ID14531 16581
RailroadLehigh & Hudson RiverLehigh & Hudson River
CountryUSAUSA
Whyte2-8-22-8-2
Number in Class44
Road Numbers70-7380-83
GaugeStdStd
Number Built44
BuilderBaldwinBaldwin
Year19161918
Valve GearWalschaertWalschaert
Locomotive Length and Weight
Driver Wheelbase (ft / m)16.50 / 5.0316.75 / 5.11
Engine Wheelbase (ft / m)35 / 10.6736.08 / 11
Ratio of driving wheelbase to overall engine wheelbase 0.47 0.46
Overall Wheelbase (engine & tender) (ft / m)68.21 / 20.7971.38 / 21.76
Axle Loading (Maximum Weight per Axle) (lbs / kg)
Weight on Drivers (lbs / kg)216,000 / 97,976221,500 / 100,471
Engine Weight (lbs / kg)290,000 / 131,542290,800 / 131,905
Tender Loaded Weight (lbs / kg)168,000 / 76,204188,300 / 85,412
Total Engine and Tender Weight (lbs / kg)458,000 / 207,746479,100 / 217,317
Tender Water Capacity (gals / ML)9000 / 34.0910,000 / 37.88
Tender Fuel Capacity (oil/coal) (gals/tons / Liters/MT)14 / 1316 / 15
Minimum weight of rail (calculated) (lb/yd / kg/m)90 / 4592 / 46
Geometry Relating to Tractive Effort
Driver Diameter (in / mm)57 / 144863 / 1600
Boiler Pressure (psi / kPa)190 / 1310200 / 1380
High Pressure Cylinders (dia x stroke) (in / mm)25" x 30" / 635x76226" x 30" / 660x762
Tractive Effort (lbs / kg)53,125 / 24097.1254,724 / 24822.42
Factor of Adhesion (Weight on Drivers/Tractive Effort) 4.07 4.05
Heating Ability
Tubes (number - dia) (in / mm)220 - 2.25" / 57216 - 2.25" / 57
Flues (number - dia) (in / mm)38 - 5.5" / 14040 - 5.5" / 140
Flue/Tube length (ft / m)21 / 6.4019 / 5.79
Firebox Area (sq ft / m2)300 / 27.87280 / 26.01
Grate Area (sq ft / m2)100 / 9.2966.70 / 6.20
Evaporative Heating Surface (sq ft / m2)4155 / 386.013783 / 351.45
Superheating Surface (sq ft / m2)964 / 89.56882 / 81.94
Combined Heating Surface (sq ft / m2)5119 / 475.574665 / 433.39
Evaporative Heating Surface/Cylinder Volume243.84205.15
Computations Relating to Power Output (More Information)
Robert LeMassena's Power Computation19,00013,340
Same as above plus superheater percentage22,61015,875
Same as above but substitute firebox area for grate area67,83066,640
Power L115,18014,943
Power MT619.74594.92

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