actually began production on the RSD15 while its RSD12 line was also
still being manufactured. The model entered the company's catalog in 1955 and
remained there until 1960. It was one of just a few Road Switcher models to receive the upgraded and far more reliable 251B prime mover,
which had replaced the troublesome 244 model. The six-axle RSD15 came equipped
with some serious pulling capacity at 2,400 horsepower, which was a 25%
increase over the RSD12. Additionally, thanks to its C-C truck setup (six powered axles) it offered quite
impressive tractive effort with a
continuous rating of 79,500 pounds. Unfortunately, since the company had experienced so many issues with the 244 engine many railroads were now leery of its products and the Alligator found few buyers.
Those that did purchase examples included the Santa Fe, Pennsylvania, Cotton Belt, Southern Pacific, and Duluth Missabe & Iron Range. The Santa Fe's RSD15s are of particular
note. The AT&SF was not necessarily a loyal Alco customer.
However, the company did regularly purchase from the builder trying out
most models that Alco produced. Interestingly, despite
all of the manufacturer's reliability issues by the time the RSD15 entered the assembly line in 1955 Santa Fe was quite impressed with the design.
Aside from the earlier RSD7 and Fairbanks Morse's H24-66 "Train Master,"
the RSD15 offered the higest horsepower rating available on the market at
|The nose of Santa Fe RSD15 #821 gives you a good idea as to how these locomotives gained their nickname as "Alligators." This unit is seen in Flagstaff, Arizona on July 19, 1962 just a few years after she entered service.|
This was something the Santa Fe was after as it
looked to supply ample horsepower on heavy freights crossing stiff main
line grades located in western California, New Mexico, and Arizona.
As a result the railroad wound up purchasing a sizable fleet of RSD15s, 50 in all, which
constituted nearly 58% of the total produced. They became famous on
the AT&SF system seen throughout all three states in a range of
liveries from black and silver to the "Blue Warbonnet" paint scheme. The
Santa Fe was apparently pleased with their Alligators as the units
remained in regular service well through the 1970s. After their time on the AT&SF some found their way to Michigan, working heavy mineral trains on ore-hauler, Lake Superior & Ishpeming.
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Production Roster Of Alco RSD15s
|Duluth, Missabe & Iron Range||50-55||6||1959|
|St. Louis Southwestern (Cotton Belt)||850-859||10||1960|
|A Santa Fe RSD15 Alligator, #825, leads a freight consist past the station at Flagstaff, Arizona as personnel attend to the grounds on July 19, 1962.|