I definitely can’t speak for this upcoming production but the original from 2007 had a different minimum curve depending where you looked. I’m pretty sure the catalog said O-72 but the box claims O-54 or O-60. I am very sure mine has done O-60 but like the others have said O-72 is a definite if you looking for the grey line I depends on a lot of things.
I will say typically with the UP big three what is one of the limiting factors is that centipede tender