There is a drawing and some data on the earlier BB40-8 at
http://vfco.brazilia.jor.br/ferrovias/e ... h8as.shtml
Locomotive weight is given as 160,000 kg, which comes to about 44,000 pounds per axle. The wheelbase given (metric and I didn't convert it just now) of a bit over two meters is, I guess, that for a single B truck: the two center axles on a BB "span bolster truck assembly" (there's got to be a shorter term! Doubletruck?) seem to be closer together than the two axles on a single B. The drawing is big enough that you should be able to get a fairly close approximation by measuring the drawing! (Noting that the wheels are only 36 inches rather than the 40 or more that is standard on US standard-gauge freight diesels.)
Given the way such things usually develope, I very much doubt that the BB40-9WM is any lighter, but since it is built for the same service and the earlier unit was probably as heavy as the track would stand, it probably isn't much heavier either.
These are interesting locomotives. The truck arrangement is reminiscent of the "double diesels" on the Union Pacific back in the 1960s. In both cases EMD went for a four-axle truck (on the DD35 for UP and the DDM45 for Brazil), and GE for a BB "doubletruck": two B trucks on a span bolster. For the UP, the individual B trucks were of the then-standard design with a drop equalizer; Brasil got a version in which the individual B trucks look like a meter-gauge version of the FB-2 truck GE introduced on domestic 4-axle models in about 1973.