Oh man how I miss out on this one?????
OK for the sake of argument ...all in FUN now.....just a tibit of info. UP did have the switcher in a black scheme back in the day before the Armour Yellow came about....
see... below....info provided by our very own guru Don Strack....
1940
The first switchers were delivered in an all-black scheme with striping and
11 inch yellow lettering. The lettering on the cab sides was for "Serves All
The West" on the left (fireman's) side and "Road of the Streamliners" on the
right (engineer's) side, with the word Streamliners in red (UP 1000
initially had multi-colored Overland shields on both cab sides). All switch
locomotives delivered between 1940 and 1947, when the yellow and gray scheme
became standard, were delivered in the black switcher paint scheme. Included
were the EMD NW2s 1000-1075, Alco S-2 1036-1054 (later renumbered to
1100-1118) and 1119-1153, Baldwin VO-1000s 1055-1060 (later renumbered to
1200-1205), Fairbanks Morse H10-44 1300, and GE 44 ton 1399. Locomotives
were lettered with "D.S." prefixes on their numbers, denoting "Diesel
Switch", similar to the "M" character in the road numbers of the road's
Streamliner passenger motive power, which denoted "Motor".
http://www.uphs.org/Dieselpaint.htm
here are some pics...
http://www.rrpicturearchives.net/locoPicture.aspx?id=53928
Alco out!