At what point are we hurting ourselves by having the green line bear every extension we ever make because its easy? So green line south/west goes to Nubian, Hyde, Needham, Riverside, Cleveland Circle (with provisions to cut it off), and Boston College with a theoretical, if not considered, reinstatement of the Watertown branch or a considered Harvard. North/East goes to Watertown (via porter), Waltham, Medford, Malden via Northern strand, and Everett via Broadway. THEN we layer in the Urban ring loops with the Silverline transit way added? What an operational nightmare we're creating. They are literally trying to reduce the use of the Park loop to push for the type 10s but stacking everything on it defeats the purpose. Why have type 10s if you cannot even use them?
At what point are we hurting ourselves by proposing whole-cloth megaprojects to provide service that could be provided sooner, cheaper, and much more easily by glomming off of existing infrastructure?
I'm curious as to the sourcing on the idea that they're trying to reduce the use of the Park loop, because I haven't seen that. I know plans can change, but the same 2018 MBTA documents that laid out the basic proposals for the Type 10s to the FMCB specifically stated that the Park Street loop was required for operational flexibility, so at least at that point in time the agency itself was aware of the need for the new cars to be able to use the loop, so I'm very curious if that part of the plans has indeed changed, and if there's any documentation of that.
There is obviously a saturation limit to the Central Subway and to the various bits of the Green Line outside the main tunnels, which does put a ceiling on the number of cars that can run through it. We don't even know what those numbers will look like going forward in a world of Type 10s and a proper, modernized signaling system that doesn't yet exist, so it's not exactly as though we're talking about taking the current operation and just throwing more cars from more branches at it. It's also the case that the line was designed, when it was handling numerous more branches, such that not every car/service ran to every station. So while the system does have a limit, between operational and infrastructural changes it's not likely to be anything like what it looks like today, so I think the hyperbole is a little premature.
With regards to Nubian/Washington St. in particular, I should make it clear that I don't have an objection to the idea of linking it to Congress Street/Chelsea as much as I consider it a far less preferable option to the Green Line option. Nubian has been starved of proper transit service since the Elevated was taken down with the lie that was "equal or better" replacement. That that replacement turned out to be a Silver Line bus that got shotgun-married to the Seaport/Logan service resulting in the never-built Phase III leaving it a broken mess (see the details of that debacle for why tunneling down Essex Street is a scary prospect) only increases the need for an actually-adequate replacement that serves the main goal of hitting the transfer stations in the core. A Green Line F-branch via Washington serves that goal; it would probably be slower and maybe a little less reliable than a new subway to Congress street, but, critically, all it requires is rehabbing the disused Tremont Street tunnels, a bit of tunneling from Elliot Norton Park to the other side of the Pike, an incline up out of the pit, and then surface tracks along the Silver Line's route on Washington. Not free, but nowhere in the same ballpark as a brand-new subway under Washington, and under Congress, then to the choose-your-own adventure to the north. In the real world outside of Crazy Transit Pitches, shotgun-marrying the supposed-to-exist-already proper replacement for the Elevated to the pie-in-the-sky Congress Street megaproject means it doesn't get built, just like shotgun marrying Elevated replacement to Seaport transit in the form of the Silver Line begat the Phase III debacle that makes the Nubian end of the Silver nothing more than a silver-painted bus. The Green Line option is the easiest one for actually getting the transit there; yes it's imperfect and relying on the GL for so many extensions eventually becomes untenable, but I don't see any reason to prefer a conceptually better project with a slim-to-none chance of being built anytime soon (for a route that was promised a proper Elevated replacement decades ago) versus one that's maybe less perfect on paper but a hell of a lot easier and cheaper to do. One of the two is way more likely, in my opinion, to go from Crazy Transit Pitch to actual functioning transit.
). My point was not specifically about the visual impact, so much as the broader political/cultural impact. The Central Artery wasn't hated just because it was ugly, it was hated because it tore the city in half and and functioned as a psychological and physical barrier between the city and its waterfront. The idea of putting anything elevated along the Greenway would provoke backlash disproportionate to its effect on the views because of that history (not to mention the fact that it would detract from the park, and ruining green space also tends to make people touchy). Part of what makes that different from Ink Block is that the existing roads and railroads around Ink Block are part of the bargain to anyone who wants to live there; if they're eventually decked over that's great and an improvement, as opposed to the idea of taking a current open space in the Greenway and (partially) decking it with an elevated railway. Respectfully, in my opinion we go beyond Crazy Transit Pitches into God Mode territory if we simply ignore the political/community horror that would accompany any suggestion of putting anything elevated along the Central Artery route.