The Milwaukee Road used a total of three different
locomotives to pull the consist between Chicago and Olympia, WA in the
early 50's - two electrics (used on electrified portions of the journey)
and the EMD FP7 - a specialized variation of the F7A which was
lenghtened to accomodate a larger water resevoir for its steam
generators (a necessity for long distance passenger service like that of
the Olympian Hiawatha). While E units could also have filled this role
(and did, in later years), their A1A truck design (spreading their
weight and giving them less traction) made them less than ideal for
handling the steep grades of the Milwaukee's route through the Rocky
Mountains.
For the Olympian Hiawatha release, Kato will be
making a new FP7A locomotive and a new tooled version of the F7B
featuring a winterization hatch (a necessity for trips through the
northern US and across the Rockies!)