Is there really a need for a HSR network in Scotland though? Edinburgh and Glasgow are only 50 miles apart so you could achieve the same journey time by running selected services non stop using the loops already on the E&G line. Dundee and Aberdeen are far enough from Glasgow but is there really the demand to justify the costs?
The proposed Dunfermline bypass line along with a reopened Glenfarg route would no doubt improve the Edinburgh to Perth/Inverness journey time by 30 minutes or so but at several hundred million can a business case really be made for at best an hourly service?
You could transform Scotland's intercity routes:-
Phase 1 - Glasgow-Edinburgh HSR.
Phase 2 - Inverkeithing-Perth/Tay Estuary Spur - speeds up Edinburgh-Perth/Dundee/Aberdeen/Inverness journeys.
Phase 3 - Link the G2E HSR line to the Fife Line - speeds up Glasgow- Dundee/Aberdeen journeys.