Even if a transit infrastructure project is announced and then funded right after an election, it would take up most of a term for the pre-project work to be completed before shovels even hit the ground. There’s utilities that would need to be mapped and relocated, land to expropriate to start, which I believe has to happen before contracts are signed.
Then there’s always going to be a vocal opposition group throwing obstacles in a major project, whether it’s because there’s no train station serving villages and hamlets, or the sight of a train will ruin people’s views of sprawling parking lots, or groups of people whose land is being expropriated at fair market value not wanting to give up property and going through legal challenges which take time to sort.
Even writing this out, it seems like a transit project does take a great deal of political will to push through, especially before shovels hit the ground.
With our current political representation setup, a big swing in majority governments means that an opposing party in power can just rip up contracts and pay out the penalty fees (or legislate away recourse for a project cancellation) which takes much less effort and provides an immediate win for their side.
That sounds like a sweetheart deal that’ll comeback to bite the STM in the coming years. Definitely Quebec is a somewhat refreshing edge case that proves that transit can be built fast, though it feels like it would be difficult to replicate on a level of building/rehabilitating several hundreds of kilometres of rail running between multiple city centres.