My understanding is that the problems of NYC -> Boston high speed rail are purely political, and basically come down to CT resistance to change

The current track alignment is not conducive to high speed travel, and CT as a state has no interest in supporting a new alignment that is conducive because they would likely get _negative_ value out of it: as it stands, Acela trains pretty much all stop in New Haven and Stamford: why wouldn't they?

If you go with a high speed link that aims to speed up Boston <> New York travel, it's more likely that you have trains that skip those stops, because additional stops are much more expensive for HSR from a speeding up and slowing down perspective, from a percentage of time added to trip perspective, and for an inefficient alignment perspective.

In my view this is kind of a microcosm of the political problems of the geographically small states of the north east: states like CT/RI/DE especially have very narrow and niche concerns but because of their geographical position have effective veto power over regionally important things like "how expensive are the tolls to drive between New York and DC?" and "can you have HSR between new york and boston?"

Yeah that's true, even in the Netherlands our high-speed line between Amsterdam, Rotterdam and Antwerp was a nightmare. It cost billions, way more than budgeted, many of the bridges turned out to have construction faults (despite all the cost overruns) so the trains aren't able to actually go fast, and the high-speed trains were bought on a budget and had so many flaws that the Belgians refused to allow them. Now we're stuck with a non-highspeed train on the track that was supposed to be highspeed and cost a fortune to build.

In other countries like Germany, France and Spain the high-speed network works like a dream though. Though the good stuff is all nationally focused.