Roger,
The units are ex-EMD sd40-2's and sd40t-2's. They've been modified for narrow guage (meter guage I think) operations in South America. Part of the exercise is to add axles, to reduce loads, and part is usually to also reduce height for clearances. There are lots of ex-North American EMD and GE products adapted to narrow guage operations in South America.
Some units have shorter fuel tanks, to make room for the additional truck length. Others, like the sd40-2 variants, have had their frames lengthened to maintain the fuel tank size while adding room for the trucks. That's why the front and rear porches are so long.
Often, the fans are recessed into the roof, or moved elsewhere. The sd40t-2, exemplified by the ex-DRGW unit, has had the dynamic brake grids and fans moved into the cavity at the rear of the carbody where the screens for the radiator air intake are located. The radiator fans themselves are already located inside the carbody on the tunnel motor locos, so they do not need to be moved.
Note the horn located on the face of the cab, which is another modification for clearance.
There is a fellow out on the west coast somewhere, named Edson Yamazaki, who models quite a few of the South American prototypes, including the bb40t-2.
https://pbase.com/tracktime/image/150961381https://pbase.com/tracktime/image/150961380https://pbase.com/tracktime/image/150961395Yes, those are 4-axle EMD trucks on that sd45. The problem isn't the wheelbase, but rather the axle loading.
Jim
P.s. They may need to clear off the roof to allow for the increase in top of rail to top of deck due to adding in a span bolster between the trucks. Not sure about that, but it makes at least a little bit of sense.
P.p.s. Lots of photos at the following link. There are some models that were built new by EMD apparently, and many more that are rebuilds. If you scroll down to the Rebuilt EMD section, you can find many more photos, including markups on modifications, as well as photos of the various changes during and after rebuilding.
http://pedrop.rrpicturearchives.net/modelList.aspx
