Come on, there's clearly efficiencies to be made given the land is mainly purchased and there are designs in place. Phase 2a is far less complicated than Phase 1 so a lot of the issue phasing Phase 1 aren't relevant. There's far less scope for government changing scope. Also the mitigation measures might be able to be reduced without impacting the actual line. There's also scope for efficiency savings through reduced speeds (although that want be huge).
Plenty of HS2s issues arent engineering related too. Its obviously pretty easy to adopt a new procurement strategy and given a decent proportion of the land is owned by the government, ground surveys can be undertaken which de-risks the potential engineering challenges.
Ground surveys might de-risk the potential engienering challenges in that they make them obvious, but they don't make them go away.
If anything is found the project will have to redesign the whole section nearly from scratch.
And if you want to reduce speeds to save money on engineering..... then the designs will have to be redone to account for this!
The below link suggests £5bn without Euston and 2a and £20bn with it.
https://news.railbusinessdaily.com/...-projects-potential-concession-value-to-20bn/
It is by Highspeed Rail Group so is lobbying but it will at least be prepared by somebody with more expertise on the matter than either of us.
£15bn uplift is probably not much more than Phase 2A and Euston will cost even if things go relatively well from here on out....
The upside risk to the cost will be absolutely enormous.
It's not going to be £1 billion a year in subsidy. Given that there's no immediate subsidy or government spending, the bond markets couldn't care less. France uses private finance to subsidise HSR and the world hasn't fallen in. The bond markets are worried about £10s billions a year, not £10s of millions.
If the a private sector body is going to be spending £20bn on a concession they are going to want to extract something like £2bn from it every year after operating expenses are covered.
The world of near zero interest rates are well and truly gone.
That £2bn will have to come out of the railway budget, because functionally HS2's only customer will be the state.
It is functionally signing the government up to £2bn in addtional spending every year for decades.
The bond markets will most certainly notice this, they are always alert for wheezes like this by desperate chancellors and will price accordingly.
In any case:
As to the design of Phase 2A...... given that we are apparently now actually doing NPR the environment has changed rather dramatically since the route was selected in 2009.
If, as it appears, a fast line will be between Liverpool and Manchester Airport, and a fast approach into Manchester from the Airport....... what is gained by going via Crewe?
The fastest route from London/Biormingham to Liverpool is likely to be to go to the Airport then along the east west line.
We would probably want a chord from the East West line to the WCML in any case to allow it to relieve the lines through Bolton, or it could certainly be added at comparatively low cost.
That means the fastest route to the northern WCML is probably going to be via Manchester Airport and joining the WCML near Warrington or wherever.
North Wales trains can't be fully electric so probably can't use HS2 in any case, and could always proceed to Handsacre regardless.
After that, most of the rationale for going to Crewe seems to just... fall away.
The route via Crewe imposes a significant dog leg and doesn't serve the primary urban areas between Manchester and Birmingham.
