The streamlined engines like this one pulling the Pacific Limited are called E4s (E class engines) by the Chicago & North Western. Their wheel arrangement is 4-6-4.  Chicago and North Western had nine like this designed to pull fast passenger trains. They were built in 1938 by ALCO or the American Locomotive Company in Schenectady, NY.   For more railway photos unrelated to Ames, try this site and this one.