The main reason for HS2 is to increase capacity: existing routes are full! Talking of upgrading existing lines is to give current travellers regular doses of purgatory. A good example of this is when the WCML was upgraded a few years ago. The works were hugely delayed, grossly over budget and what did it produce? - marginal line speed improvements and a footpath the length of the line. Anyone who wants to have bus replacement services every weekend and overrunning engineering works affecting weekday running is welcome to promote upgrading the existing network.
I have endured the Thameslink upgrade through London for the last five years and that will not be complete until 2018: it was originally promoted as Thameslink 2000! For all these reasons that is why HS2, HS3 and others are long overdue. Then we can upgrade the existing lines with alternatives in place. Projects such as Crossrail show how it can, and should, be done.
Tim
