Yupp, that's just like the NZR's quill drives, except that we have a narrower gauge and the axle goes all the way from wheel to wheel! (just joking :-)
The driving axle still needs vertical movement in relation to the electric motor and I don't like the sound of the quill springs slapping loosely between the driving wheel spokes =8^] I had something like that on an old Triumph motorcycle "sprung-hub" rear wheel once the rubbers wore out - it wasn't nice and I'd guess it would be even worse on a loco wheel, given the forces involved!
Greg.P. NZ