Cab-forward No. 4114, shown here in a Baldwin builder's photo, was a member of the AC-5 group delivered in 1929.

(ausdew, Public domain, via Wikimedia Commons)



Southern Pacific Railroad's AC-5 class of steam locomotives was the railroad's second class of 4-8-8-2 cab forward locomotives. They were built between July and September 1929 and placed in service soon after construction. The AC-5 class was only slightly larger than the AC-4 class.

The first locomotive of this class, number 4110, holds the dubious honor of being the first 4-8-8-2 cab forward locomotive to be scrapped when it befell this fate on February 3, 1953, at the railroad's Sacramento, California, shops. The rest of the class were removed from service and scrapped by mid-1955. None of this class was preserved.


SP,  BLW. Train No. 60 hauled by an early Baldwin built Mallet No. 4118 of cab foremost design.

Engine is of 4-8-8-2 type at speed of about 40 mph. ca. 1940s.

(Railroads: Photographs, Manuscripts, and Imprints’ digital collection at DeGolyer Library, Southern Methodist University, Texas)


A Gallery from 1952.


Southern Pacific cab-forward on freight passing Berkeley bound for Oakland, CA, August 16, 1952. (Brooksbank, CC BY-SA 4.0 <>, via Wikimedia Commons)


A lengthy Southern Pacific fruit train pulling away eastbound from Berkeley, CA. August 14, 1952. (Brooksbank, CC BY-SA 4.0 <>, via Wikimedia Commons)

Southern Pacific cab-in-front 4-8-8-2 Mallet at Oakland, CA, August 15, 1952. (Brooksbank, CC BY-SA 4.0 <>, via Wikimedia Commons)

Forward half of a Southern Pacific 4-8-8-2 disconnected from its tender, showing the elaborate connections, inside the Locomotive Depot at Oakland, CA, August 15, 1952.(Brooksbank, CC BY-SA 4.0 <>, via Wikimedia Commons)


Southern Pacific cab-forward 4-8-8-2 at Oakland, CA taking water or oil  into its immense tender, August 15, 1952. (Brooksbank, CC BY-SA 4.0 <>, via Wikimedia Commons

Southern Pacific cab-forward 4-8-8-2 westbound to Oakland on an endless freight passing Berkeley, CA, August 14, 1952. (Brooksbank, CC BY-SA 4.0 <>, via Wikimedia Commons)


Type and origin
Power type: Steam
Builder: Baldwin Locomotive Works
Serial number: 60866–60869, 60884–60889, 60952–60957
Build date: July–September 1929
Total produced: 16
Configuration: Whyte 4-8-8-2
Gauge: 4 ft 8+1⁄2 in (1,435 mm) standard gauge
Driver diameter: 63 in (1.600 m)
Adhesive weight: 482,500 lb (218,900 kg; 218.9 t)
Locomotive weight: 622,600 lb (282,400 kg; 282.4 t)
Boiler pressure: 235 psi (1.62 MPa)
Feedwater heater: 41⁄4-BL Worthington
Cylinder size: 24 in × 32 in (610 mm × 813 mm) (bore × stroke)
Performance figures
Tractive effort: 116,900 lbf (520 kN)
Operator: Southern Pacific Railroad
Class: AC-5
Numbers: 4110–4125
First run: August 16, 1929
Retired: 1955
Disposition: All scrapped