The pistons were NOT torched off. They had to use a good sized hammer to knock out the keyed wedge holding it together; similar to a Morse taper on drill press.
However, one other 4000 had their pistons cut when they seized during the move to a museum, schedule was pressing and time was urgent.
This move's speed was restricted to 20mph, never exceeded 25. I was actually surprised that they moved so fast, honestly never expected more than 10-12mph.
As for real max, designed for 80mph, not intentionally ran above 70 in regular service. Some folks say one of them hit 83 on a troop train. Normal operating speed 35-50mph. So for the future? Whatever the FRA permits on the track rating, I presume.
Ben:
1. IDK you tell me.
2. Big Boy could navigate 20 degree curves, more of a problem with overhang than radius.
2b. Not mine, no place to put it.