>For instance I assume a city government couldn't compel, say, librarians to get smallpox or yellow fever vaccine given actual infectious disease risks in MA in 2023.

And if there ever was - somehow - an outbreak of smallpox or yellow fever, I would 100% expect librarians to be covered under any govt-mandates regarding vaccines for those diseases.

If you're going to use hypothetical arguments, at least make sure the whole thing matches, rather than picking and choosing.

An EUA is being approved. An EUA is authorized during public health emergencies, after all the hurdles regarding efficacy and hazards have been cleared, but the rest of the bureaucracy hasn't been completed just yet. There never were any "unapproved" vaccines or treatments floating around, at any point (excluding the times when covidiots were suggesting bleach enemas and horse de-wormer),

As I said: one line at a time.

So, yeah, it probably would take a couple of decades to do all the work. But it wouldn't be a couple decades of "No trains".

At this point, I'd be cool with them ripping all the hardware - rails, ties, switching, everything, even concrete in places where it needs to be repoured - out of the tunnels, and replacing it all with modern gear, one line at a time. And then they do the red line and orange line, dig another tunnel or two to connect the commuter rail between North Station and South Station. Would probably have to replace entire lines with bus service for years, while the line was being gutted and rebuilt, but it's honestly getting to that point. There is only so much you can do when you need spend half your maintenance time just getting equipment in and out of the tunnels. And maybe if we're really good, we can finally have the yellow line. As a treat.

Big-Dig-it-up, but for public transportation this time.

The main issue with this is that it would severely impede water changes in the bay. It would effectively be a sewer in fairly short order, if you tried to build sea walls between the harbor islands. You could maybe build a lock system between Castle Island and the Airport, and that would be small enough that you could submerge the whole system except during storms (like the Thames River, and the Venice Lagoon) and it would protect the waterfront in downtown, but you couldn't do that to the entire bay.

>Interestingly, that motion is anti-aligned with our motion about the galaxy, which means the Milky Way itself is moving at about 550 km/s with respect to the CMB.

So, given enough time for the sun to finish swinging around to other side of its orbit, will its net velocity WRT the CMB be ~150km/s?

Yeah, but counter point: you don't have to shovel rain.

Straight into the harbor, I say! There is room, and it would mesh with the spirit of past major construction projects.