Southern Pacific class AC-11

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Southern Pacific class AC-11
Southern Pacific class AC-11
SP 4274 leading an excursion train out of Reno, Nevada, on December 1, 1957.
Power type Steam
Builder Baldwin Locomotive Works
Serial number 64677 – 64706
Build date November 1942 – April 1943
Configuration 4-8-8-2
Gauge ft 8½ in (1435 mm)
Driver size 63 in diameter
Weight on drivers 531,700 lb
Total weight 657,900 lb
Boiler pressure 250 psi
Feedwater heater 6SA Worthington
Cylinder size 24 in dia × 32 in stroke
Tractive effort 124,300 lbf
Career Southern Pacific Railroad
Class AC-11
Number 4245 – 4274
First run November 24, 1942
Retired 19541958
Disposition scrapped

Southern Pacific Railroad's AC-11 class of cab forward steam locomotives was the seventh class of 4-8-8-2 locomotives ordered by Southern Pacific (SP) from Baldwin Locomotive Works; SP was so pleased with the AC-10 class built a year earlier that the railroad began placing orders for AC-11s while the AC-10s were still being built and delivered. They were built between November 1942 and April 1943, closely resembling the AC-10s.

The first AC-11, number 4245, entered service on November 24, 1942, and the last, 4274, on May 9, 1943. SP used these locomotives for between 12 and 15 years, with the last retirements from this class occurring on September 24, 1958. Shortly after their retirement, the AC-11s were scrapped, with the last, number 4262, on August 27, 1959.

[edit] References

  • Diebert, Timothy S. and Strapac, Joseph A. (1987). Southern Pacific Company Steam Locomotive Conpendium. Shade Tree Books. ISBN 0-930742-12-5.
Cab forward steam locomotives of Southern Pacific Railroad
2-6-6-2: MM-2 (rebuilt as 4-6-6-2)
2-8-8-2: MC-1 · MC-2 · AC-1 · MC-4 · AC-2 · MC-6 · AC-3
4-8-8-2: AC-4 · AC-5 · AC-6 · AC-7 · AC-8 · AC-10 · AC-11 · AC-12
Preserved: SP 4294 (AC-12)