Something else I think should be noted is that despite the historical prestige we saw with some East Coast Main Line rolling stock, I believe some of Beeching's recommendations for development of major trunk routes would mean that all London-Scotland traffic would be funneled along the West Coast Main Line while the east would stop short at Newcastle. This never happened of course, but it is somewhat reflected by the original HS2 service plans before the Y-shape was butchered into what it is today where all Scotland trains ran up the west coast.
The Elizabeth Line might be premier by the standards of a London commuter line, but it's not exactly a backbone of the nation's railway compared to something like the WCML which connects the most major metropolitan areas and population centres along with carrying almost half the UK's rail freight traffic.Given that “premier” means “first in rank” what about the Elizabeth Line (also nicely named after a Head of State)?
It might even have more journeys than any of the other candidates.
You're very welcome! Always a pleasure to get people caught up on Railway Series lore!Thank you - that’s saved me a hour or two tonight!