As a railway buff, I know a lot about the current network and journey times. I can be in Kings Cross in two hours from the front door on a good connection now.
HS2 won't be any quicker from here because getting to it will take just as long as now, and you can lose 20 minutes on a connection.
Much of the current system has capacity for four tracks because there used to be four. Occasionally there are bottlenecks where viaducts enter cities, such as North of Sheffield and North of Leeds.
The Woodhead line from Sheffield to Manchester is almost intact and could be reinstalled without much effort.
The whole HS2 project stinks of jobs for mates, and based on the Panorama priogramme, many people will pay dearly by being under compensated for business disruption and house CPOs.
Work has started in Birmingham around the old Curzon Street station. Now that is a building worth bringing back into use. The oldest surviving station building from 1838.
https://en.wikipedia.org/wiki/Birmingham_Curzon_Street_railway_station_(1838-1966)
