USA Trains, NW2 block: 28mm dia. 84mm centres.
Bachmann, 37mm dia. 87mm centres.
You would need to cut the 'axle extensions' off the USA-T block. This block is the same width, but a lot thicker. - 27mm(B) to 39mm(USA). Top of block to axle centre-line is 15mm(B), 25mm(USA).
The Bachmann block has contact strips on the top, and there are 'fingers' to connect to these on the bottom of the tram. - There are also 'spacers' these fingers are screwed to. Removing these gives you 6-7mm more height for the taller USA-T block.
The side-frames fit to the Bachmann block in four holes (in the side) they are just sprung in. - I drilled holes in the USA-T block, so fitted in same way.
Couple of not very good photo's:
Unmodified tram sitting on USA-T block (no side-frames) height (ignoring end of ruler, so more than this!) to underside of tram: 45mm.
Original Bachmann block: 40mm
Trust me.. The angles are wrong, so the dimensions look wrong on the photo's. - Remember I am just quoting the number, there is that extra bit on the ruler..
So by taking the spacer-bits off the bottom of the tram (you have to sort the wiring anyway) it comes out about right.