Matt: I haven't seen anything about this RS-1 being a Washington Terminal engine. It was built in March 1941, build # 69425, and started with the CRI&P (Chicago Rock Island & Pacific) as #749. According to one source, a post on a forum, it was requisitioned by the Army, numbered #8006, and was sent to Iran. Later it was bought by the Alaska Railroad, and numbered 1042. Later it went back to the Army, then to the TVA (Tennessee Valley Authority), and was numbered #48. That one source said it then went to Midwest Coal Handlers, but I haven't seen that anywhere else.
Here is a link to a photo of this RS-1 when it belonged to the Alaska RR:
http://www.alaskarails.org/pix/former-loco/JS-1042.htmlThe caption under this photo has some info, but it isn't exactly the same.
Here is another link to a roster for the Alaska RR, which has some of the same info for engine #1042:
http://www.trainweb.org/rosters/ARR.htmlThe following link is to a roster for model RS-1:
http://www.thedieselshop.us/Alco_RS1.HTMLLook for road number 749, opposite the name Chicago Rock Island & Pacific (first column). #748 is next to #749. Over in the middle column are the build numbers for both. There is no subsequent history for this engine, but it gives the beginning.
One more link, to the forum where I found a bit of history:
http://www.rypn.org/forums/viewtopic.php?f=1&t=29773 I saw that old engine parked out there (couple weeks ago), and saw that it was different, probably an Alco, so I made a picture. Didn't know what I had for a while. Finally looked it up. Very old one. I didn't know any diesels were made that far back. Anyway, it is interesting. I'll include a close-up of the cab, cropped out of the large photo of this engine, which is a cropping of the original photo that includes more than just the Alco. I included a 700 pixel version of the whole engine with my first post on this subject. This close-up shows the #48, and the letters "TVA".