Another possibility-
The old Kalmbach "Second Diesel Spotter's Guide" has a photo of a Missouri Pacific RS-3 rebuild that, in profile, looks a lot like the unit in the pics. With a similar manifold on top with 3 stacks. The photo does not show the roof, so I can't be certain about the fans, but it is described as being rebuilt with an EMD 567 prime mover, and those fans look like EMD fans.
The photo is MP 1080 (original number was in 961-999 series), which they referred to as a "GP-12" and they also rebuilt RS-11s, and called those "GP-16". MP rebuilt quite a few, the dates of the rebuilds according to the book are 1964-65.