>>1509812>It's technically viable to live in Providence and commute to Boston, and vice versa
It's been viable for decades. Commuter rail has always been active as far south as Attleboro, which is painfully easy to get to from Providence. The T extension in '88 made BOS-PVD commuting an absolute no-brainer.>Acela reaches its top speed in RI
Both between East Greenwich and Kingston in Rhode Island and between Attleboro and Sharon in Massachusetts are the only 150mph segments of the NEC as of posting this, making Mansfield the most dangerous train station in America, since it's on a 2-track line with a limit of 150mph, and mostly low-level platforms, and the mini-highs it has are deteriorating.>>>1509691 is right, the major impediment to cutting down the time on the Boston-NYC run is Connecticut. Eastern CT is very twisty and New Haven to NYC is plagued with low speeds and delays.
That, and Southeast CT STILL has 11 level crossings, all of which can (and should) be grade-separated. Sure, it'll necessitate a rebuild of New London and Mystic's station platforms, but it's more than worth it. Between New Haven and New Rochelle is owned by Metro-North; it's a lost cause to speed it up without legal action.