Those narrow gauge GEs are neat -- their couplers are truck mounted and so they swing as the trucks pivot. If I'm remembering correctly, the smaller ones, like the "Golden City & San Juan" #4 in the photo, have their two trucks pinned together under the center of the unit, so they make really interesting motions on curves. Big Al" #7 has a fuel tank between its trucks, so its trucks are not pinned together, but its steps are truck mounted, so those swing out on curves (like Lionel diesels.)
Here's a photo of #7 pulling two coaches on the D&SNG back in 2014:
Railpictures.net #550521Note the small cab and how the fireman is riding the platform.