Well, I didn't know how they were powered, but I do know that the folks at Strasburg had worked on at least one Disney engine that was in the shops in 2019.
Tweetsie Railroad's shops at Blowing Rock, NC used to do a lot of Disney steam work in the past, but apparently hasn't in a while.
Of course, they couldn't name the Corprorate Mouse by name.
I took the WDW steam tour in 2010, it was great (if you ever do it, BAIL from the tour once it gets to Maintstreet Station, as it regressed into a insomnia-busting lecture of Disney railroad history when we did it).