> Axial movement is controlled by the inside of the wheel boss bearing
against the flange of the axle box, as in the plain type.

I considered doing the same, but felt that the advantages of needle
roller bearing would be negated by the friction of the wheel boss
bearing against axlebox to provide axial bearing - maybe it is my
usual tendency to evercomplicate :-)

Would be interested in the success of your arrangment and any
practical findings once you tested it.

May I suggest that you post pictures etc in the "Files" section rather
than in "Photos" (very limited in size and quality.

thanks
Chris