Well... it’s possible with at least two of the three railroads you named. As far as I know the CSX is still not very open to any steam on their rails however they have been allowing the 765 group to make some short movements on their mainline out in Ohio these past few years. Anything is always possible, just takes the right people and corporate goals to come together. The UP 844 and SP 4449 Pacific Northwest double header back in 2007 is a good example of never say never.