Freight and light rail physically cannot share the same tracks by definition. The catenary height of the hblr and the nec are different. But yea exactly the common carrier laws are pretty strong to prevent forced abandonment or any kind of eminent domain by the state

So in both of these proposals, the highlighted blue section (not the blue line but the blue highlight) is Norfolk Southern owned tracks that still serves active customers. And there is no way they would allow freight shifting on a light rail track, not to mention it wouldn’t even fit under the catenary. Good luck getting them to give up their active line.