Thanks for posting.
There's lots of fascinating detail in the Wrexham-Bidston document - £207m!
The NW electrification project is costed at £200m and buys you about 90 double-track route miles.
This has some significant complications (Manchester approaches, Chat Moss, Farnworth Tunnels etc).
Wrexham-Bidston is 27 of the simplest miles you could find on NR.
So why does it cost any more than say £70m?
£200m doesn't even buy you speed increases or signalling upgrades.
The steel sleepers on the route would need to be replaced for DC.
The study was only done on a DC basis, and the whole ethos of NR is now pro-electrification instead of anti, so maybe a new study on an AC basis would produce a nicer figure.
Anyway, I think the debate has moved away from the "where can we usefully extend the Merseyrail network?" to "how quickly can we get strategic routes wired?"
On this basis Wrexham-Bidston, useful as it is, falls behind the main lines.
As I mentioned in another thread, I'd go for wiring Wrexham-Chester(-Crewe) first.