That's not how it works.

With such big projects, the decision that really matters is the start of the main construction tenders.

When the 'decision' is a joint government or even EU-level declaration, that can be drawn out indefinitely, with repeated joint declarations that now we really mean business. Or worse, the decisionmakers might be only willing to pay for preliminary studies, and sell those as the start of the project, but then solicit ever more studies (an example: Brenner Base Tunnel). Even when the decision is tendering the detailed plans, that may be followed up by several plan modifications, or disputes over the price tag that may delay the construction tender (example: Malmö city tunnel), even indefinitely.

I should probably do a diary on it

You should!

(And with the political boundaries clearly drawn, I'd be curious at contrarian comments from other ETers versed in Swedish politics ;-) )

_{*Lunatic*, n.
One whose delusions are out of fashion.}