Hi Lynn, I would like to add my condolences as well, on your loss.
Just to expand a little. The model you have was produced by Atlas in 2001, part number 42030, as shown. It can be found in Atlas's archives, which is where all the RS-3 models are listed. It appears to be DC (direct current) controlled, which is the basic electricity used on most U.S. models of the time. The N over H Logo, stands for the New Haven railroad, now, being no longer in existence, known as a "fallen flag". The real one, or as we model train nutters call them, "prototype", was built in 1950. The #520 is it's roster number among the locos owned by the New Haven RR'd. Here is the link to that Atlas Archive. Scroll down to the very bottom to find your locos listing. At the top, beneath the picture (Great Northern sample) is information both on the "prototypes" and the model's features.
http://archive.atlasrr.com/NLoco/arc-nrs3.htm
Here is a photo of #529, a relative of #520 showing what Alco diesels were famous (infamous?) for and earned them the title of honorary steam engines. This was the last surviving RS-3, the photo is from 1986. It's last one was taken in 2013 at the RR'd museum of New England,
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when it was said to be about to receive a new motor
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