At this point, notice several important things:
1) There might be some very small metal washers around the axle of the removed wheelset
As far as I can tell these are only for making sure there isn't too much side-to-side
slop in the axle sliding back and forth. If you can, I just re-used those washers
on the replacement axleset - but if you didn't do that, I don't think it would matter.
2) The silver truck sides can separate, so be careful they don't separate too far
3) You can see the small hole that the axles ride in. Carefully make sure that the
replacement wheelset's axles are placed back in these holes when you re-assemble
4) Work slowly, carefully, under good light, observe carefully, and you should not
have problems.
I hope all this helps. John Sing ATSF_Arizona http://home.comcast.net/~j.sing