One of the drivers of cost has been the high speed part. It meant the route needed to be straight which meant more tunnelling to avoid certain areas. Lower speed track would have allowed them to route around problem areas.

China has run at 360kmh before, but last I checked they mostly run slower.

Air resistance is a killer as you go faster. So for trains 300 is usually about the best compromise between energy use and speed. If you want to go faster a jet at altitude is going to be much faster at a better fuel efficiency. High speeds make sense for long distances.

> Max line speed of HS2 is 360km/h, with provision for 400 in some sections in future.

That's already been reduced to 320 km/h under this year's "HS2 reset". Which I imagine in reality will be 300 km/h normally at most, with even lower speeds seen day to day

Interestingly the written report to the government stated "However, no railway in the UK, or globally, is currently engineered for 360 kph". Are you incorrect or did they forget to include China in their research?

Anyway, I thought these were last decade's talking points? I thought it was all about capacity now, not speed? Except I thought there were also rumblings about reducing capacity from the previous announcements? Hard to keep up...!