But even if thats true I still doubt HS2 will be finished before 2026 for phase 1, some ten years away and stage 2 in 2032 and therefore HS3 is unlikely to begin before then never mind finish. I just don't believe the resources will be available to complete the jobs simultaneuously and thats without consideration to Crossrail 2.
I sympathise with your view, working in the civil engineering industry, it's clear that staff numbers are really ramping up... My office in Manchester has a huge proportion of engineers with good degrees and good experience, from Ireland, Spain, Greece and Poland for a start, there's an Iraqi, another guy from Napal and even a bloke from Barnsley ! These mega projects have a degree of commitment that is coming through into the private sector, my current firm and previous firms are both massive US firms, with very talented staff around the world, we currently outsource work to India... The construction industry will be doing the same - when staff and equipment is needed, it's found - where the difficulties come are with artificial constraints - primarily access time restrictions to track.