Banner
Navigation
loco-info.com
The reference for locomotives and railcars
Navigation
Random
Search
Compare
Settings
Southern Pacific classes AC-7, AC-8 and AC-10 to AC-12
go back
United States | 1937
143 produced
AC-7 No. 4154 shortly after its delivery in 1937
AC-7 No. 4154 shortly after its delivery in 1937
R.J. Foster / collection Taylor Rush

After the AC-6 class cab forwards, 26 slightly larger AC-7 class locomotives were built in 1937. They were technically almost identical to their predecessors and differed visually in that they had a larger tender and a cab that was sloped at the front. The two frames of the locomotives were now cast together with the cylinders in one piece each. These were followed by 27 almost identical AC-8, 40 AC-10, 30 AC-11 and 20 AC-12. The last AC-12 was also the last steam locomotive to be built for the Southern Pacific. These five subclasses were retired between 1954 and 1959. So far there is only a short text for this vehicle. In the future it will be described in more detail.

VariantAC-7, AC-8AC-10 to AC-12
General
Built1937, 19391942-1944
ManufacturerBaldwin
Wheel arr.4-8-8-2 
Gauge4 ft 8 1/2 in (Standard gauge)
Dimensions and Weights
Wheelbase66 ft 10 in67 ft 3 in
Rigid wheelbase16 ft 10 in
Total wheelbase112 ft 2 in
Service weight639,700 lbs657,900 lbs
Adhesive weight514,800 lbs531,700 lbs
Total weight934,700 lbs977,900 lbs
Axle load67,000 lbs69,100 lbs
Water capacity22,000 us gal
Fuel capacity6,400 us gal (oil)6,100 us gal (oil)
Boiler
Grate area139 sq ft
Firebox area513 sq ft478 sq ft
Tube heating area5,992 sq ft
Evaporative heating area6,505 sq ft6,470 sq ft
Superheater area2,988 sq ft2,615 sq ft
Total heating area9,493 sq ft9,085 sq ft
VariantAC-7, AC-8AC-10 to AC-12
Power Plant
Driver diameter63.5 in
Boiler pressure250 psi
Expansion typesimple
Cylindersfour, 24 x 32 in
Power
Power sourcesteam
Indicated power6,000 hp (4,474 kW)
Starting effort123,364 lbf
Calculated Values
steam locomotive
freight
passenger
Articulated
cab forward
last changed: 03/2023
AC-11 No. 4269. Note the staff member on the “Monkey Deck”
AC-11 No. 4269. Note the staff member on the “Monkey Deck”
collection Taylor Rush
Search
loadding loading...

We use cookies to save the following settings:

  • selected navigation structure
  • selected language
  • preferred units
  • spelling of railway company names

If you refuse the use of cookies, the settings will only be retained for the current session and will be reset to the default values the next time you visit the site.

Display of units

Here you can set the desired unit system for the technical data.

  • Metric: Lengths in meters, weights in tonnes, and volumes in cubic meters
  • Imperial (UK): Lengths in feet/inches, weights in long tons and volumes in imperial gallons
  • Imperial (US): Lengths in feet/inches, weights in pounds, and volumes in US gallons
  • Individual: Depends on the country of origin of each locomotive
Operator names

Here you can set the display of railway company names.

  • Short: Abbreviation or short form of the name
  • Standard: commonly used name, partially translated to English
  • Complete: full name in local language