Schnellzug
Established Member
The tunnel's open access- but I bet there's no requirement that the Shuttle terminals are, and I doubt that you could take a shuttle-sized carriage very far past the terminal without it be hilariously out of guage.
They'd be within the loading gauge as far as London on HS1, wouldn't they? How about a lorry shuttle as far as some convenient interchange point with the m25, saving a fair bit of trucking around London.
doing nothing innovative for years, by now we should have had all sorts of things like this.