Hi Russell,
It is true that MTH Electric Trains was making extra shells this past run for people with cracking shells. It is also true that they only made enough for the people that had contacted them before that build was made. They should be coming this spring, but all are spoken for.
I finally got around to contacting MTH parts and sales on March 21, 2022, and the message above was what I got back.
I have three Box Cab units from the 2008 run that are cracking so I guess I'm SOL.
If anyone else contacts them and receives a different response, please post it so we can all see it. Thanks
Russ