Welsh Govt took the decision to take responsibility away from NR for upgrading the CVL after the massive cost overspend and delays with GWML electrification and NR's inability to stay within budget with the Ebbw Vale re-doubling project, which as is known, had to be abandoned after NR blew the allocated budget pretty quickly.
So to answer your Qs. 1) WG took the decision to upgrade the CVL after the failiure of the projects mentioned above and didn't trust NR to stsy within budget after GWML and Ebbw Vale failiures.
2) No idea, but there's a well known, finite budget available for the CVL, we've already seen the CVL re-scoped several times to stay within budget.
3) No, it's all being done to Network Rail heavy rail standards, even though the CVL through Pontypridd will be 100% tram-train operation, so in theory there's no need for more expensive HR standards to be applied to these lines (but you already know this I suspect
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