Good point the WCML was badly in need of upgrading anyway, as the last time it was modernised was when it was electrified in the 60s & 70s, all the infrastructure was knackered, they were only papering over the cracks, train times were slow compared to other main lines, London to Glasgow via the WCML took 5 to 6 hours
It's now about 15 years since the major WCRM renewal and upgrade works on the WCML.
That's just about the time interval that it took for the original WCML electrification (London-Birmingham-Manchester-Liverpool) to become troublesome, and it got steadily worse over the next 20 years before WCRM was authorised.
BR did not keep up with the obsolescence of the kit installed, some of it pre-1960 and designed originally for 90mph running.
It's to be hoped that the maintenance regime under NR has kept the present infrastructure in good shape, despite the hammering it gets at higher speeds and frequency.
We don't want to have another WCRM in the 2030s.
Both WCML projects (original electrification and WCRM) also starved other parts of the railway of investment, as they consumed all the cash and priority for a decade each.
WCRM was split into three incremental projects, core, PUG1 and PUG2.
Core was the bulk of the work and would have been needed whatever solution/franchisee was chosen (110mph).
PUG1 was the 125mph tilt upgrade we ended up with, PUG2 was 140mph south of Crewe which was canned.
Only the PUG1 upgrade was really attributable to the eventual Pendolino project.
However, I'm not sure RT/NR ever really planned the work in these phases.
I suspect much of the route is fit for 140mph (track/OHLE) but stymied by the cab signalling issue over 125mph.