I bought this set of engraving bits some time ago from a tool seller at a train show. Not sure if the diameters are metric or English units.
I use them to smooth journal pockets, enlarging, cleaning and reaming holes, etc.
The two I use the most are the ones with shrink wrap tubing on them for better grip as I don't like to use these in a drill, unless the rpm is slow.
The other bit I use is a Dremel 105 bit for the very bottom of the journal pocket. Its size is between the one on the left and the second from the left.
The other bit with the shrink wrap, is sized perfectly for an Micro-Trains bolster pin shank.
Just thought I'd share.