The GCR is of course the only preserved main line railway, not merely some sort of branch line. By nature of the original engineering work when the line was built, much more recently than any surviving main lines I might add, the alignment can take a lot more than 25mph. Some of it might still be the fastest alignment we’ve got.
Churnet Valley was a double-track, 60mph mainline back in the day. In fact many of our heritage railways were built as more than light railways originally, GWSR / NYMR to name just two. GCR might be the only double-track preserved line, that is simply beacaue there was the will and determination to create such back in the 90s.
Why does Staffordshire, or indeed any county council own any disused railway trackbed if they have no intention of the line reopening? Obviously you would build a new entrance to the theme park immediately adjacent to the station, geared towards people arriving by rail and not by road. Nothing says visitors would actually have to scale a cliff face of any height by hand.
It's currently set up as permissive footpath, used extensively by walkers, dog-walkers, horse riders and cyclists. Not all railway trackbeds need to be re-opened. Not only have you got issues at Alton, but at Oakamoor there is the bridge over the River Churnet at Oakamoor that will need significant repair, Oakamoor tunnel is now a protected bat habitat (and you can't just smoke them out), a new level crossing requires installation the other side and at Oakamoor station itself the old access road bridge was demolished and the road diverted onto the former trackbed so this will need replacing. As for the park entrance, if it was that easy it would of been done by now, but it hasn't as how do you scale such a cliff-face - especially in the days of access for all?
There is a need (and capacity) for more trains to run to Manchester Airport from the south, but do you propose Stoke - Leek to be electrified, or for Diesels to run under the wires all the way from Stoke to Manchester Airport? Llandudno is less of an issue due to the lack of electrification from Crewe onwards.
They haven't got the money to open Stoke to Leek as it is, let alone upgrade for electric! However that is a complete non-starter as well, as the Council can only actually re-open Stoke to Leek Brook Junction (SCQ1 and SCQ2). LBJ to Leek is under a 150-year lease to CVR, and whilst they are obliged to grant access to any mainline connection I can never see OLE being approved onto a heritage operation.