Where on earth is there clear blue sky thinking on this topic please? We are into the minutiae of line speeds, loops, line capacity etc when we haven't even got a route.
Perhaps we need to stand back and remember what we had seventy years ago, on nationalisation when effectively the GNR and the LNWR got their own back on the Midland and the Great Central - by closing them down.
London to Manchester was available from Marylebone, St Pancras and Euston. Inter Regional journeys spurred in and out along the way allowing all sorts of exotic journeys such as Bradford to Paignton, Manchester to Bournemouth, the Harwich Boat Train etc. Suggest that now and you get some bean counter telling you what is affordable - result - half of the Borders line built single track - madness!!!
The few miles of line from Millers Dale to Matlock must re-open and the negotiations there are with PPPB and Haddon Hall. We should hear no more about congested WCML. No wonder the poor thing is full - its trying to carry the capacity of three lines and more- see above.
Woodhead needs to follow - with a triangular junction at Penistone and a curve where the current tram depot is at Sheffield to access Midland. No need to electrify Standege. We have an electric tunnel but Network Rail would prefer you forget about it!
Now you have three routes from the Great Wen to civilisation again, plus renewed capacity to the North and North East again, choices of inter regional, diversionary routes, and multifarious reasons why HS2 is not the answer - I know it won't happen - so do you - but at least someone is thinking out of the box!