Here is a thought - there are no real repair facilities or equipment at the CHS owned railroad. Perhaps it is more cost effective for Railstar to have the maintenance performed this way.
Who owns #9? I think the CHS does - so they may have control over the repairs and not Railstar.
As to #12 - it would make sense to outsource the new axles to the D&S who has the capability and experience to make new axles for the #12.
Railstar is going to do the re-assembly of the two locomotives. Perhaps in time, Railstar will be able to obtain the tools necessary to do these kind of repairs. The D&S had to purchase these tools and equipment - it did not happen overnight - same with the Ashbys. The C&TS outsources their driver repairs to the D&S.
So try getting off Railstar's back. Rome wasn't built in a day.