I think it would be great to have a class 55 " Deltic" locomotive on our collection! One of the legends of engineering that made a history...
My absolute dream route would be ECML Peterborough to York or if that's a bit too long Peterborough to Doncaster in late 70s with Deltics and HSTs with valentas.
Like what matt#4801 says we would need the ECML along with the deltics. It would be fun thrashing vintage diesel locomotives at 100mph or 125mph down the ECML. I completely agree with you.