Southern Pacific 4294 is a class " AC-12" 4-8-8-2

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 ...

type

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 locomot ...

that was owned and operated by the

Southern Pacific Railroad The Southern Pacific (or Espee from the railroad initials- SP) was an American Class I railroad network that existed from 1865 to 1996 and operated largely in the Western United States. The system was operated by various companies under the ...

(SP). It was 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 t ...

in March 1944 and was used hauling SP's trains over the

Sierra Nevada The Sierra Nevada () is a mountain range in the Western United States, between the Central Valley of California and the Great Basin. The vast majority of the range lies in the state of California, although the Carson Range spur lies primarily ...

, often working on

Donner Pass Donner Pass is a mountain pass in the northern Sierra Nevada, above Donner Lake and Donner Memorial State Park about west of Truckee, California. Like the Sierra Nevada themselves, the pass has a steep approach from the east and a gradual appro ...

California California is a U.S. state, state in the Western United States, located along the West Coast of the United States, Pacific Coast. With nearly 39.2million residents across a total area of approximately , it is the List of states and territori ...

. Today it is preserved 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 Historic ...

(CSRM) in

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

History

No. 4294 was the last of 20

Southern Pacific class AC-12 Southern Pacific Railroad's AC-12 class of cab forward steam locomotives was the last class of steam locomotives ordered by Southern Pacific. They were built by Baldwin Locomotive Works during World War II, with the first, number 4275, entering s ...

4-8-8-2

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 ...

locomotives in a larger series of 256 Southern Pacific articulated cab forwards starting with class AC-1. Articulated locomotives are essentially two locomotives sharing fire box, boiler and crew. The front locomotive has its cranks quartered 90 degrees apart. The front and rear drive axles are free to roll out of phase with respect to each other. If unloaded, the locomotive has a vertical oscillation, near 50 mph, that can lift the tires above the rails. Its most distinguishing feature was that the cab and firebox were at the front of the locomotive instead of the traditional rear. This was done essentially by running a 2-8-8-4 machine backwards with appropriate modifications. The engineer and fireman swapped sides and faced away from the firebox. The tender remained behind the locomotive to maintain the improved forward vision; this was possible because the locomotive burned Bunker C fuel oil rather than

coal Coal is a combustible black or brownish-black sedimentary rock, formed as rock strata called coal seams. Coal is mostly carbon with variable amounts of other elements, chiefly hydrogen, sulfur, oxygen, and nitrogen. Coal is formed when dea ...

, so the fuel could easily be piped from the tender to the firebox, unlike a coal-burning locomotive. The smoke box end coupling was strengthened. The power reverse lever ( Johnson Bar) and steam

throttle A throttle is the mechanism by which fluid flow is managed by constriction or obstruction. An engine's power can be increased or decreased by the restriction of inlet gases (by the use of a throttle), but usually decreased. The term ''throttle'' ...

motion direction were reversed. The drive wheel axles were also reversed, end for end without rekeying the return "fly" cranks, to reverse the expansion link timing on both sides. SP4294 Standard Fly Crank

The cab forward design was useful in the long tunnels and

snow shed Avalanche control or avalanche defense activities reduce the hazard avalanches pose to human life, activity, and property.Sacramento, California ) , image_map = Sacramento County California Incorporated and Unincorporated areas Sacramento Highlighted.svg , mapsize = 250x200px , map_caption = Location within Sacramento C ...

, where it was put on outdoor display October 19, 1958 at the SP station next to the '' C. P. Huntington'', the railroad's first locomotive. Construction for

Interstate 5 Interstate 5 (I-5) is the main north–south Interstate Highway on the West Coast of the United States, running largely parallel to the Pacific coast of the contiguous U.S. from Mexico to Canada. It travels through the states of Califor ...

necessitated a move for the locomotive and it was stored in the SP shops until May 1981. At that time it was moved again, this time to its current location, the

, where it remains on static display. If it had never been for the negotiating efforts of the Railway and Locomotive Historical Society in the 1950s, No. 4294 likely would have been scrapped along with all of the other SP cab forward locomotives. As a result, No. 4294 is the only SP cab forward that has been preserved. At one time, it was hoped that No. 4294 could be restored to operating condition. According to CSRM personnel, the biggest impediments toward such a project are the estimated costs and the current policies of both

Union Pacific Railroad The Union Pacific Railroad , legally Union Pacific Railroad Company and often called simply Union Pacific, is a freight-hauling railroad that operates 8,300 locomotives over routes in 23 U.S. states west of Chicago and New Orleans. Union Paci ...

and

BNSF Railway BNSF Railway is one of the largest freight railroads in North America. One of seven North American Class I railroads, BNSF has 35,000 employees, of track in 28 states, and nearly 8,000 locomotives. It has three transcontinental routes that ...

in regards to operations. The cost of such a restoration is estimated between $1 million and $1.5 million, an amount that the museum feels would be prohibitive given the current prospects for its eventual operation.Wyatt, Kyle K., Curator of History and Technology, CSRM, August 21, 2007.

History

References

Further reading