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 ...

's MC-4 class 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 locomot ...

was the second class ordered and built as

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. Southern Pacific (SP) found the MC-2 class sufficient for a proof-of-concept for cab forward locomotives and sought to continue with now tested designs. In service, SP found that the locomotives were a little too slow for the traffic needs. By 1930, all of the MC-4 class had been "simpled" to use uniform size cylinders and feedwater heaters were installed to address the issue. They were then reclassified as

AC-2 Yellow / AC-2 (Atlantic Crossing 2) is a submarine telecommunications cable system linking the United States and the United Kingdom. The cable is wholly owned by CenturyLink (formerly Level 3 Communications) in the US following its acquisition ...

locomotives. As rebuilt, the locomotives continued in service through the end of World War II.

References

* MC-4 2-8-8-2 locomotives Baldwin locomotives Mallet locomotives Steam locomotives of the United States Railway locomotives introduced in 1911 Scrapped locomotives Standard gauge locomotives of the United States {{steam-loco-stub