> Part of the issues are that the funding and construction resources and accountability here is much higher for cars here whereas it’s for trains there.

Not sure what you mean about this. We're already looking at spending $850M on a connector; surely that kind of money gets us a <5 year timeline. 8 years is just... insane. NYU has been studying the GLX project for example (study here), we spend significantly more than many other countries on transit as is.

> A second piece is mitigation like managing detours, noise, and utility reroutes as mentioned above. There’s also more uncertainty about what’s under the ground and where it exists, which requires more exploratory digging and planning.

Yeah so maybe I was hybolic about it being done in 2 years. I still don't see how this basic extension takes 8 years to complete. It's a pretty critical extension too, since the lack of a connector leads to more people using the Green, Orange and Silver Lines instead of just hopping on the Blue Line and skipping a third transfer altogether. That added traffic/inconvenience really drives people to drive over just leveraging our pretty awesome (for American standards) public transit system. Especially as more people look to live and work around Cambridge, Somerville, Eastie, Revere, etc.