Re: Silver Line to Chelsea (Study Meeting)
I'm assuming nothing they do with this extension will prevent an eventual conversion to LRV UR. Are they building it in such a way that it makes a future conversion fairly simple (if possible)?
F-line, you've talked before about LRV UR tracks running north of the CR tracks when crossing over the Mystic. But eventually, somewhere in Chelsea (just east of Broadway?), it would have to cross over the CR tracks to get to stay on the ROW and get to the Chelsea bridge on its way to the Airport. Does this require a flyover, or can LRV trains simply cross over CR tracks? And I apologize if i've asked this question in another thread, I've been to ask for a while now and can't remember if i've typed it or not.
Flyover or flyunder. No way is it safe to cross at-grade diagonally in a blind spot like that. Would have to switch sides between where the Everett Terminal spur peels off at the 99 rotary and 2nd. Note there's that small stream next to the tracks near 2nd; that goes underground at 2nd into a culvert, turns south, and empties into the Mystic at the boat landing on Beacham St. On the other end it crosses directly under the tracks in a culvert, turns north, and goes underground between Spring and Paris streets (about a third of the way west of Spring).
If it's a duck-under you probably have to do it between the stream culvert and the rotary on that grassy median separating the freight turnout from the commuter rail tracks. And assume that the stub freight storage tracks that end at 2nd have to go and be compensated by new storage tracks constructed in the terminal (plenty of unused land for that).
If it's trolley you'd do something like the Wellington tunnel on the Orange Line, only shorter. Wellington incline + tunnel is 1000 ft. long because it carries commuter rail too...you can go way shorter and steeper at full speed on a trolley, like you do through all those pretty steep Green Line portals. 500-700 ft. in length is probably enough to whip down and up without making your stomach unsettled from the G's.
Bus...harder, a lot harder. You're gonna have a really difficult time working in a longer dip between the stream and the curve by the rotary, and a dip + quick transition onto the curve is gonna come at a painful speed penalty. And we know how painful the speed penalty in a Silver Line tunnel can be. Flyover bridge is probably the only practical way to switch sides if they're that wedded to BRT. In which case the stream doesn't matter much and they have more running room to work with...but the residents along Paris St. aren't going to be happy about that ugly-ass ramp rising high above their backyards.
Alternately, as *trolley-only* (not bus) they can shove a duck-under between 2nd and 3rd if the 3rd grade crossing is outright closed (which should've been done long ago except that Peter Pan Bus would scream and bitch about losing its back driveway shortcut across the tracks). Narrower land strip, though, so might involve taking a few feet from abutters to do the dip. No compelling reason to attempt it if the rotary area has space (Paris St. residents don't care about a tunnel they can't see). But this is not an option for BRT as flyover
or duck-under...too much width, guaranteed property takings. And if/when the 2nd grade crossing is eliminated it'll be on a road bridge over the tracks, so a flyover can't be done between 2nd-3rd-Market Basket (nowhere near enough room to rise halfway to the sky). Basically, there has to be some disastrous engineering blocker around the rotary for this location to be the fallback option because the westerly site is superior in every way except for *certain aerial circumstances only* re: the Paris St. residents.
All of this is why they are is no way in hell they'll consider wrapping this ongoing Silver Line build around to Everett if the casino is built. Not even some Wynn Fun Bucks sweetening the pot are going to float the cost in extra steel and concrete for switching sides.
Of course,
anything you build as BRT can be converted to rail later. Or shared by bus and LRT if tracks go in the pavement, because these buses are not running in electric mode on the surface. That does beg the question: why build something twice for twice the price? But politicians don't have the spatial reasoning skill to ask themselves that one on account of all the crayons shoved in brain during childhood, so. . .
