Is the quarry not part of the Preserved line? that may explain why it's being maintained a bit better than might be expected.It would be interesting to see the Meldon Quarry be re-opened. I went down there this August and was shocked at how well preserved things were. All signals seemed in order and there was even some rolling stock and standby.
If not for Quarry uses, could the Meldon site be used as a freight hub? It would be the only such hub west of Exeter and with decent road links to North and Central Devon might be worth investigating
Regarding the Freight hub, I'm afraid I will prove @BrianW prophetic and ask, what business is there for a freight hub in that part of the world, given the difficulty of getting trains to it. If there was business for it, you'd have a hub at Exeter with the M5 as well as the A30, and the much bigger city.