THE MOST RADICAL DESIGN CHANGEin
American steam power evolved from one simple
fact: Southern Pacific’s Sacramento Division up
and over the Sierra Nevada subjected crews to ap-
proximately 30 miles of suffocating tunnels and
snowsheds. Thus, for safety’s sake, came the
unique cab-forward locomotive, in which the en-
gineer’s and fireman’s controls were switched, al-
lowing for what essentially was backward run-
ning. The first were MC-2 2-8-8-2s of 1910. The
concept reached full bloom beginning with the
10 4-8-8-2s of the AC-4 class in 1928. Eventually
SP would buy a total of 195 AC engines. At the
height of the war, SP ordered 20 AC-12s, the
road’s last new steam as it turned out. The
cab-forwards operated over much of the SP sys-
tem, from the Cascades of Oregon to the deserts
of New Mexico, but they were identified most
strongly with battling the snows of Donner Pass.
The last one to be built is also the only one to sur-
vive: 4294 at the California State Railroad Muse-
um in Sacramento.
Southern Pacific AC-12 4-8-8-2
Waging war
in the Sierras
Southern Pacific AC-12 4278 (a Baldwin product,
like all the cab-forwards) departs Santa Barbara
with a westbound Coast Line freight. The fireman is
watching his smoke, while a few cars back a brake-
man is up on a roofwalk. E. J. Lukas