I think I mentioned this before but I think the line to Zebulon is perfect for a Tram Train. Run on the train tracks from Zebulon to WakeMed, and then on-street (by adding tram tracks to the upcoming BRT lanes) from there to DTR. (And, perhaps, from there on through to the line to Fuquay, which is similar from a traffic perspective.)
This would probably require time separation - meaning running freight trains in the middle of the night. It’s a bureaucratic headache but from an ops perspective it should be feasible. There are several freight customers along Yonkers Rd in Raleigh, but few between WakeMed and Zebulon, none with high volume, and no through freight at all anymore to the best of my knowledge.
Battery-Electric multiple unit hybrid trains are getting to the point where they would be quite practical for a line like this. This is a 30 mile line, you could have trains charge at the endpoints and then probably make the entire run off-wire with ease.