Most rail cars are not actually owned by the railroads that bear their reporting marks. Many are owned by banks, investment trusts, car builders, leasing companies and more.
The same applies to locomotives too. Very few of either cars or locomotives are owned by the railroads for which they operate. Many of the older reefers that the UP did own,
the 57-footers, were sold to leasing companies that rebuilt the cars and updated their heating and cooling systems to comply with California clean air rules and it was then that
the reporting marks were changed from UPFE or SPFE to ARMN. The leasing railroad does basic
upkeep but when something big happens, like in this case, then the car owner may be on the
hook for the repair. If the repair is costly, and the car is over a certain age, then the owner may decide to scrap the car. (Sometimes if the car is newer, but in low demand, the car may also be scrapped.) If this car has sat as long as has been stated, it is quite possible that the copper thieves have ruined the car, or have stolen the diesel generator,
or in some way made the car in worse shape than it was and the additional damage might finish it off. And before the rivit counters get excited, I do know that some recently built reefers also have ARMN reporting marks.