USRA Heavy Mikado

USRA Heavy Mikado
Type and origin
Power typeSteam
BuilderALCO, Baldwin, Lima
Build date1918–1944
Total produced233 originals, plus 724 copies
Specifications
Configuration:
  Whyte2-8-2
  UIC1′D1′ h2
Driver dia.63 in (1,600 mm)
Wheelbaselocomotive: 36 ft 1 in (11.00 m)
Fuel typeCoal
Fuel capacity14.5 t (14.3 long tons; 16.0 short tons)
Firebox:
  Grate area70.8 sq ft (6.58 m2)
Boiler pressure190 psi (1.31 MPa)
Superheater:
  Heating area92.25 m2 (993.0 sq ft)
CylindersTwo, outside
Cylinder size27 in × 32 in (690 mm × 810 mm)
Valve gearWalschaerts
Loco brakeWestinghouse air brake
Train brakesWestinghouse air brake
Performance figures
Power output3,194 hp (2,382 kW)
Tractive effort60,000 lbf (270 kN)
Career
Scrapped1938-1961
DispositionAll scrapped

The USRA Heavy Mikado was a USRA standard class of steam locomotive designed under the control of the United States Railroad Administration (USRA), the nationalized railroad system in the United States during World War I. These locomotives were of 2-8-2 wheel arrangement in the Whyte notation, or 1′D1′ in UIC classification. A total of 233 locomotives were built to this plan for the USRA; postwar, it became a de facto standard design, which was built to the total of 957 locomotives including the USRA originals and all subsequent copies.

Heavy Mikado used the same running gear as the USRA Light Mikado but were built to a higher axle load, larger cylinders and a much larger boiler for more power and steam-generating ability. Many aspects of the PRR L1s class were carried over to the Heavy Mikado, although not that locomotive's distinctive Belpaire firebox.