Southern Pacific 4294, a cab-forward steam locomotive

Under the Whyte notation for the classification of

steam locomotive A steam locomotive is a locomotive that provides the force to move itself and other vehicles by means of the expansion of steam. It is fuelled by burning combustible material (usually coal, oil or, rarely, wood) to heat water in the loco ...

s, a 4-8-8-2 is a locomotive with four leading wheels, two sets of eight

driving wheel On a steam locomotive, a driving wheel is a powered wheel which is driven by the locomotive's pistons (or turbine, in the case of a steam turbine locomotive). On a conventional, non-articulated locomotive, the driving wheels are all coupled ...

s, and a two-wheel trailing truck. Other equivalent classifications are:

UIC classification The UIC classification of locomotive axle arrangements, sometimes known as the German classification''The Railway Data File''. Leicester: Silverdale, 2000. p. 52. . or German system,Kalla-Bishop P.M. & Greggio, Luciano, ''Steam Locomotives'', Cre ...

: 2DD1 (also known as German classification and Italian classification)
French classification: 240+041
Turkish classification: 46+45
Swiss classification: 4/6+4/5 The equivalent

is refined to (2'D)D1' for Mallet locomotives. A locomotive of that length must be an articulated locomotive; meaning all have a joint between the first and second groups of driving wheels. All examples of this type are

cab forward The term cab forward refers to various rail and road vehicle designs that place the driver's compartment substantially farther towards the front than is common practice. Rail locomotives In steam locomotive design, a cab forward design will ...

s. Normally, the leading truck sits under the smokebox and the trailing truck under the firebox. On a cab-forward, the leading truck supports the firebox and the trailing truck and smokebox are at the rear next to the tender. A 4-8-8-2 is effectively a 2-8-8-4 that always runs in reverse.

Southern Pacific

The Southern Pacific was the only railroad to operate engines of this wheel arrangement, all of which were built by the

Baldwin Locomotive Works The Baldwin Locomotive Works (BLW) was an American manufacturer of railroad locomotives from 1825 to 1951. Originally located in Philadelphia, it moved to nearby Eddystone, Pennsylvania, in the early 20th century. The company was for decades ...

. A total of 195 were produced between 1928 and 1944 in eight batches. The later ones had cylinders 24 inches by 32 inches, drivers 63-1/2 inches and boiler pressures of 250 psi, giving a calculated tractive effort of 123,400 lb. The locomotives were built as cab-forwards to protect engine crews from exhaust smoke and heat in the many tunnels and

snow shed Avalanche control or avalanche defense activities reduce the hazard avalanches pose to human life, activity, and property.Mallets'' these cab-forwards were built with simple expansion cylinders. The name stuck because the original classes of Southern Pacific cab-forwards were built as compound Mallets, though these were eventually converted to simple expansion machines.

Southern Pacific 4294 Southern Pacific 4294 is a class " AC-12" 4-8-8-2 Cab forward type steam locomotive that was owned and operated by the Southern Pacific Railroad (SP). It was built by the Baldwin Locomotive Works in March 1944 and was used hauling SP's trains o ...

is the only cab forward that was not scrapped when the locomotives were withdrawn from service. It was donated to the City of

Sacramento, California ) , image_map = Sacramento County California Incorporated and Unincorporated areas Sacramento Highlighted.svg , mapsize = 250x200px , map_caption = Location within Sacramento C ...

in 1958, but had to be moved due to freeway construction. It was subsequently given to the State of California, and is on indoor static display at the

California State Railroad Museum The California State Railroad Museum is a museum in the state park system of California, United States, interpreting the role of the "iron horse" in connecting California to the rest of the nation. It is located in Old Sacramento State Histor ...

in Sacramento.

References

General reference

External links

Web Site of ToyTrains1 4-8-8-2 Cab Forward Steam LocomotivesSteam Locomotive.com's Southern Pacific Cab Forward article, including detailed specs.
{{Whyte types 88,4-8-8-2 Simple articulated locomotives