F-Line to Dudley, thank you for all the detail.
This is moderately off topic, but I personally doubt that there's enough development demand to justify any deck over any Widett Circle or environs yard in the next 20 - 30 years. That area is so isolated from everything that it would require new elevated access roads connecting to Dorchester ave or the bypass to support the scale of most developments. The exception would probably be monolithic constructs like Hudson Yards, or a new stadium, mall or convention center, where I'd hope there's a provision for a infill station on the Fairmount under it all. Now I admit that's no reason not to include a provision of columns and whatnot (as long as you don't lose the plans for them) but I wouldn't want to saddle the project with the financial burden of underwriting it all.
That said, is there any reason the T wouldn't air rights Cabot yards first, where the potential parcels are more manageable in scale, can possibly directly tie into the Travellers/Fourth st bridges, and has the "desirable waterfront" of the Bass River? It's basically the only thing seperating the new developments of SoWa and Broadway.
The Red Line yard is spaced for air rights pegs on the Travelers/4th blocks, so no question those are head-and-shoulders above Widett on desirability. Moreso once the SSX project logjam gets unstuck and Dot Ave. gets re-knitted together into the area by Broadway. Blame our regional ineptitude on planning anything air rights-related for those not being hotter parcels than they are. If we can't make hay on the Pike parcels at all, even the attractive siting of those Cabot super-blocks are unfortunately a reach too far.
The reason this is such a hot topic with Widett's future is because the Olympics bid just *had* to impale itself on ironclad promises that the Widett 'bowl' would be decked over, become a major Games facility, then be turned over to private redevelopment. Blame Boston 2024 for inverting the air rights order-of-priority that way, but unfortunately because they raised the stakes there so high it becomes a major point of negotiations. The fatal flaw there that upended it all was sticking one Master Developer with all the risk. And also pooh-poohing any MassDOT involvement on the lower-level, thinking that would just be pornographic number of parking spaces for Olympic Stadium or whatever.
So with the BDPA still having acid fever dreams of supertalls rising above a deck there, Job #1 on the land sale is baking in the M.O.U. provisions of how the deck would be underwritten by the permanent ground-level transpo easement and chaining the property taxes for the redev to amortizing the deck costs. At very minimum you have to "fix the glitch" that killed it for B24's Master Developer hail-mary or the barely-cooperative-on-a-good-day BDPA will simply never play along on a MassDOT transaction that's needed ASAP. "Underwriting" wouldn't mean sacking the project up-front with costs.
The T's own layover analysis says the track spacing will be compatible with peg mounts...a zero-cost design provision. It's more that since we've already proven that no developer on earth--not even with Olympics-size slush funding--finds acceptable risk in building the deck on their own dime, that the only means possible is if there's public funding for that part.
That's where the property tax 'lockbox' comes in as source of amortization funds, and MassDOT can also trade out its outright ownership sooner to a land 'trust' and flipping itself to just perpetual ground-level easement. The land trust can then chart a multi-decade course as clearinghouse for all air rights manners, much like South Station did eons ago for air rights that took till 2020 to become relevant. They can slow-walk it all they want because they do have the luxury of near-infinite time before they actually find somebody willing to build here.
The important thing is just inking the M.O.U. up-front so those transitional institutions can start doing their thing troubleshooting the deep long-term. That also qualifies as "fixing the glitch" from the Olympics disaster trying to do too much too soon on too many over-assumptions.
I fully agree with you that we'll all be dead before something ever rises on a deck there, because the location is what it is for craptacular access and in real-world pecking order won't be touched until we figure out how to infill the Pike canyon and Traveler/W. 4th superblocks. Which themselves will never happen without a drastic sea change in the utter brainlock that thwarts everything air rights-related in this city. So consider all of that a paper-only exercise settling up the "what-if's" as means-to-end for the institutional cooperation...and not anything that's odds-likely to be consequential in real 'concrete'.
If we get real lucky one of these decades with a compelling redev-on-deck proposal, then it's all gravy to have done the existential handshakes up-front and to have gone to the trouble to paper-enumerate the mechanisms. Serves same good as the South Station air rights dept. forming but not getting its first bite for 35 years.
I don't think we would've been all that surprised or deeply disappointed if SS Tower vanished into more vaporware because that's what we were conditioned to expect all along. But boy-oh-boy if that tower stays on-track for construction schedule does that mid-80's decision to form the SS air rights trust get retro-lauded as visionary. Same at Widett. If nothing ever happens, then we still solved the practical problems of perma-solving CBD transit storage (noting as well the bus coattails for post-NSRL reapportionment) and got the generally half-cocked Food Market relocated to pound-for-pound more efficient facilities in service of stabilization of local wholesale prices.
And BDPA and its umpteen planning successors have perpetual jerking-off material to keep them forever occupied even if nothing ever happens, which is probably a safer bet than letting their minds wander to too many new urban renewal canvases where their involvement instantly starts breaking shit.
Those are eminently good and productive outcomes even if you put zero stock in anything ever rising out of the 'bowl'. But in the one-in-a-million chance something ever does rise???...visionaries! Nothing whatsoever to lose by getting their stories straight up-front on that.