BB40T-2s are standard EMD SD40T-2s that were sent to FCA (Ferrovia Centro-Atlantica SA) in Brazil. FCA operates a large (4,400 mile) meter-gauge rail network, and was created when the nationalized Brazilian railway, FEPASA. was broken up and privatized in 1996. To meet the need for additional power, FCA and the other new
Brazilian railroads have been importing second-hand US power and regauging it to run either on the meter-gauge network or on the broad gauge (5 foot) system. For meter gauge conversion, usually the fuel tank is shortened, a span bolster is put in, and where each truck was before, two smaller two-axle trucks replace it. In addition, units occasionally have fans and such removed from the top to deal with clearance issues on the narrow gauge system. Because the top fans for the dynamic brake housing were removed, the dynamic brake resistor grids were moved inside the fan housing at the back of the tunnel motor, and the side grills were completely redesigned. If you look at the photos of 4821, you'll see the new dynamic grids clearly.
Pedro Rezende (pedrop) on RailroadFoums.com has kept those of us here in the US up to date on these odd units, and has given me permission to repost his photos here. In addition to the photos of the units in operation, he also sent three photos of the delivery to the Port of Vitoria: