Alaska Railroad obtained four EMD SW-1 Locomotives in 1947 and numbered them 1201, 1202, 1203, and 1204.  These locos were retired by 1965.  I have poor black and white right side view of 1203 and a fair right front 3/4 view of 1204. Both shots were taken a few years after the locomotives were removed from service and the blue paint has faded to a powder baby blue.    You can represent this paint with the following Polly S colors.    Mix just enough for each locomotive and expect that each loco will vary in color just as they did on the ARR.   Hint:  Use  clear 35mm film canisters to mix your paint in as it will keep for months in the sealed container, better than in the original jar.    For the "OLD ARR. Blue" start with a 50/50 mixture of 414221 CSX Blue and 414179 SP Lettering Gray.  You can then lighten or darken it to fit the condition and age of your prototype.   For the "Old ARR. Yellow/Gold" start with 75/25 mixture of 414191 CNW Yellow and 414179 SP Lettering Gray.      For black areas exposed to the sun, I use PollyS Tarnished Black.  The shaded areas are painted flat black so they contrast with the Tarnished Black to raise details in the "sun".  The black decals are from an old Walthers set no longer available.   I am working with Rounhouse Hobbies to possibly produce a generic set of decals in various sizes to do these early locomotives.

My model of 1204 represents her about 1950 still in decent paint as she was used in the Anchorage Yard.   Starting with a Walthers SW1 the modifications are simple additions:   the box under the step on left front side of the cab, fixed shades attached to cab roof above not under the drip cap,  flag/lamp brackets on the front hood corners, a decent looking bell, larger horn, shroud around stack, cut levers, fuel fillers, single brake hose on each end and radiator water fill pipe and cap.

These SW1 switchers will look good with a string of the Cannonball Troop Sleepers and some of the converted TS Box Cars I am building for sale through the MATI gift shop.   MATI has a good stock of the Cannonball kits in stock.