It is in no way going to be a "crack" route even if HS2 East is discarded entirely.
Essentially all London-Scotland traffic will decamp to the WCML anyway once HS2 reaches Crewe.
You would be carting air up and down the ECML all day, every day, for occasional use during disruption.
That's a very very expensive way of providing "redundancy".
Bilge. The journey time from Edinburgh to Euston even if Phase 2 had been built in full was 3h 48 minutes according to the HS2 journey planner
All of 12 minutes faster than the 05:40 from Edinburgh to Kings Cross which does it in four hours precisely with a call at Newcastle, without ever exceeding 125mph.
Interestingly, the HS2 journey planner wrongly states that the fastest current Edinburgh to London time is 31 minutes slower than it will be via HS2. The correct figure is 12 minutes slower.
It then compounds this error by stating "HS2 journey time savings are compared against current rail times. Current rail times are based on current fastest regular rail journey available in either direction"
So it won't take a great deal of investment and upgrading of the ECML for it to be faster than HS2, a few billion perhaps, but nearer £3 billion than £30 billion and without tangling it up with West Coast and Midland Main Line over one pair of tracks from London to Birmingham International.
www.hs2.org.uk