Realistically, where would the Glasgow HSR terminus be located?
Edinburgh seems like it's a definite underground type solution, unless somebody is willing to get the cheque book out to drill two tunnels into the mound and under the castle, and rationalise the station layout. Glasgow seems a little less clear. St Enoch initially seeming sensible before considering the curves, and Central obviously being the prefferred option for connectivity - but with the added hastle of having to decide which adjacent street to bulldoze to make way for an extension.
I certainly can't imagine punters will be happy to see the four corners torn doon!
But then again, a new side extension to the west of Central for HSR would be a planning nightmare without a grade seperated crossover. Mind you, you could still build the west side extension to house a sizeable proportion of the regional services, and then rationalise the current layout of Central to convert 4 platforms to HSR, and allow dual gauge compatibility of UK and UIC gauge between Central and Polmadie? Keeps the regional services to one side and provides enhanced peak capacity for them, as well as allowing maximum flexibility by having dual compatibility (minus the platforms) between Central and Polmadie such that HSR lines needn't be kept seperate until crossing the Clyde into Central
The whole issue certainly is intriguing.