In reply to deacondeacon:
You're worrying me now, I'm just perusing the 1:25,000 on line and it shows a dismantled railway disappearing into a hillside and coming out the other side, and there's a farm called 'Tunnel Farm'!
You can see part of the old railway when you're coming down to Buxton on the A54.
It's just West of Buxton.