In reply to Timmd:
Since HS2 is supposedly to increase capacity, I propose we take a leaf out of the Swiss rail book.
They went for double decker trains, there by doubling their capacity, tunnels and bridges were raised or the track lowered in some places, much of it through rock. While I realise this might be a difficult job and it's sometimes harder to work in mediums that aren't rock surely it's not beyond our engineering skills to do the same.
The work was carried out over night mainly and disruption to the existing system was minimal, as far as I know.
Getting to Manchester 30 minutes earlier isn't going to make that much difference to anyone, being able to get there at a time that suits you is much better.