If it is emissions related they may be federally prohibited from transferring to the dealer until corrected.My dealer has informed me that they were able to get a couple of small bits of information from the rep.
First they said the car is not damaged, good news.
Second that the hold is for a "canister" issue.
Only thing that comes to mind with a canister is emissions. Even then it seems it would be better addressed at the dealers facility rather than in a rail yard.