Southern Pacific class MC-6

Southern Pacific Company's MC-6 class of steam locomotives is made up of two batches: the first consisting of 15 locomotives weighing 435,800 pounds (197.7 tonnes) built in 1912, the second consisting of 5 locomotives weighing 437,100 lb (198.3 tonnes) built in 1913. All of the locomotives were built by Baldwin Locomotive Works. This was the last class of 2-8-8-2 locomotives that Southern Pacific (SP) ordered as cab forward locomotives.

Southern Pacific class MC-6
Type and origin
Power typeSteam
BuilderBaldwin Locomotive Works
Serial number38523–38534, 38711–38713, 39673, 39731, 39857, 39858, 39874
Build dateOctober–December 1912 and April–May 1913
Total produced20
  Whyte2-8-8-2 Mallet
  UIC(1′D)D1′ h4v
Gauge4 ft 8 12 in (1,435 mm) standard gauge
Driver dia.57 in (1,448 mm)
Axle load51,200 lb (23,223.9 kg; 23.2 t)
Adhesive weight400,700 lb (181,800 kg; 181.8 t)
Loco weight435,800 lb (197,700 kg; 197.7 t)
Total weight615,200 lb (279,100 kg; 279.1 t)
Fuel typeFuel oil
Fuel capacity3,200 US gal (12,000 l; 2,700 imp gal)
Water cap10,000 US gal (38,000 l; 8,300 imp gal)
  Firegrate area
60.4 sq ft (5.61 m2)
Boiler pressure200 psi (1.38 MPa)
Heating surface4,177 sq ft (388.1 m2)
  Heating area5,016 sq ft (466.0 m2)
High-pressure cylinder26 in × 30 in (660 mm × 762 mm)
Low-pressure cylinder40 in × 30 in (1,016 mm × 762 mm)
Valve gearWalschaerts
Performance figures
Tractive effort94,880 lbf (422.05 kN)
OperatorsSouthern Pacific Company
Numbers4029 4048
First runDecember 17, 1912
Retired1946 1949
DispositionAll rebuilt as AC-3 class; all of which were scrapped

Locomotive number 4043, the newest of the early class of MC-6 locomotives, was displayed at the Panama–Pacific International Exposition along with SP's first locomotive, C. P. Huntington.

All but three of the locomotives in this class were rebuilt as the AC-3 class with "simpled" uniform cylinders of 22 in × 30 in (559 mm × 762 mm) by 1930. The last three were thus rebuilt in 1937. During the rebuild, 4¼-BL Worthington feedwater heaters were also installed on the fireman's side of the locomotives.

After their rebuilds, the locomotives were used through the end of World War II with the last one scrapped on August 20, 1949.


  • Diebert, Timothy S. & Strapac, Joseph A. (1987). Southern Pacific Company Steam Locomotive Conpendium. Shade Tree Books. ISBN 0-930742-12-5.
This article is issued from Wikipedia. The text is licensed under Creative Commons - Attribution - Sharealike. Additional terms may apply for the media files.