Green Line Extension to Medford & Union Sq

Arlington

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{pictures from viaduct lintel being placed upon viaduct posts}
How is something like this made earthquake proof (how do you keep the top from jumping the 4" "up" that an earthquake might jolt it?)

I've seen enough pianos and chests of drawers fall out of pickup trucks at rotaries to know that while "down" is dominant 99.99% of the time, it is not the only force that objects respond to.

Are those actually metal plates on the bottom of the lintel? (such that you could put a nut onto the bolts from the top of the posts?)
viaduct-mate.jpg
 
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Ruairi

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Was looking at this the other day, all those lintels are at the same height which seems to be something like 60% the height of the concrete charles river dam viaduct. I presume there'll be extra concrete pours to grade the track up to meet the viaduct, would it have not made more sense to gradually increase the size of the cone shaped piers as they approach the viaduct?
 

Jake_Jarmel

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Was looking at this the other day, all those lintels are at the same height which seems to be something like 60% the height of the concrete charles river dam viaduct. I presume there'll be extra concrete pours to grade the track up to meet the viaduct, would it have not made more sense to gradually increase the size of the cone shaped piers as they approach the viaduct?
You would have to consider the depth of the girders as well which will sit on top of the pier cap.
 

ceo

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Yup, look at the size of the girders they've already put up, and there's your answer.
 

sm89

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There used to be a path under the old viaduct. These columns are actually very closely spaced. Is the path/walkway not in the long term plan? It doesn't look like it can fit.
 

Arlington

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There used to be a path under the old viaduct. These columns are actually very closely spaced. Is the path/walkway not in the long term plan? It doesn't look like it can fit.
Clearly since the concrete is "fat" there's less room under there, but I think that you'd still have room to do a wider sidewalk in most places (which, under the steel EL would have been blocked by columns) or down the centerline, or on the apartment side.

Elsewhere (at the far outer end of the viaduct) this says there is 10'6" clearance between columns, good enough for an 8'6" path. Not sure if they were consistent, but it gives a sense. probably could even do
Fat concrete sidewalk
Stonedust "jogging" path along the centerline
Asphalt Bike path along the apartments' side
 

Arlington

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^ if Sullivan gets a RUR stop, looks like East Somerville / Inner Belt should too!
 

F-Line to Dudley

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^ if Sullivan gets a RUR stop, looks like East Somerville / Inner Belt should too!
Never. Not there. The only driver pushing the Sullivan superstation is access from RUR to the mega bus hub, particularly for North Shore linked-trip demand. And it's a slow-grower hedge at that, designed to safeguard from the 2-stop Orange transfer backtrack from North Station getting too overloaded after full-build RUR has swamped NS terminal with all kinds of new traffic sources. Even with that terminal saturation prospect it's expected to take many years for Sullivan RUR stop to start seeing sustainable utilization, because the RUR-induced transformation effect of linked trips enhancement really needs to sow itself across the whole system--including car-free commute options to the outer Purple Line stops--for behavior change to start cranking up demand at a bus terminal like that. The only reason the Mystic Working Group has eyeballed the build sooner is that the time to actually blow up chunks of retaining wall to create room for the Purple platforms @ Sullivan is when the City & MassDOT are executing their plans for a Square-tying grand headhouse fronting the current bunker, which will be pile-driving the shit out of enough concrete to begin with to make shotgunning construction jobs a potential cost-saver. It's widely expected, however, to take decade or more to attract more than flies at whatever platform does get carved out of that retaining wall after it does open.


There is no analogy to any other transfer stops, no matter how sky-high the surrounding TOD. Just Malden Center bus terminal and its pretty decent (at least alighting-wise) CR utilization that figures to get better with RUR frequencies, and Porter superstation. They already studied GLX/Purple superstation possibilities to the hilt in the initial scoping with Tufts and Union, finding no demand because those aren't major bus terminals. Umpteen-times rehashed "Zombie Wonderland" and "Zombie Alewife" likewise don't ever study out to demand despite presence of goodly amount of buses and promises of higher Purple frequencies because the transfers are shit-inconvenient by walking distance. For the same reason no amount of sky-high ceilinged TOD at Assembly is going to get an RUR stop plunked there, East Somerville will never qualify eiher. One 15-min. mode to one 6-min. mode simply isn't a behavior-changing draw. You need buttloads of frequent buses fanning out across the compass from a bona fide terminal--and the multi-modal rail transfer--to make it cook as a prospective superstation. The predictive data there has been so rock-solid consistent across a multitude of service configuration scenarios that it overpowers the quality/quantity of surrounding TOD.

East Somerville is mega TOD...especially after McGrath gets mercifully boulevarded. But it is not, in that best-case future, yet a diverging-route terminal of extreme significance...so the demand for a superstation isn't going to materialize no matter how high the neighborhood's fortunes go. Superstations consistently require certain discrete X-factor ingredients on the linked-trips. Many, many stratospheric dev. centers existing and future go big without ever having those ingredients...and thus they aren't ever superstation candidates despite their bigness.
 

vanshnookenraggen

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To piggy back on that, I've always felt that Regional Rail proponents (in all places) have far higher ambitions for their proposed systems than reality can deliver. The greatest advantage of RUR in Boston is for folks on the North Shore to get to South Station and Back Bay in one ride. Beyond that you're playing simcity.
 

George_Apley

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To piggy back on that, I've always felt that Regional Rail proponents (in all places) have far higher ambitions for their proposed systems than reality can deliver. The greatest advantage of RUR in Boston is for folks on the North Shore to get to South Station and Back Bay in one ride. Beyond that you're playing simcity.
Yeah, certainly the potential is there to allow much greater flexibility in the where you live/where you work calculus, but the idea that it will radically remake the development patterns of the past 75 years is unlikely. Boon to Gateway Cities maybe, but not a rail-commuter-topia.
 

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Spotted this morning: the next stage of retaining wall work beyond Ball Sq (to Tufts/Medford) has started, with
- on the GLX side of the right of way behind the Tufts outbuildings along Boston Ave, they're constructing a low knee wall that will hold the future ballast of the GLX trackbed.

- based on this, it can't be long now before they have to take the corresponding space that's currently used as the "back way out" of the car wash at Titan Gas (https://goo.gl/maps/amDpjepRHMER2uR79) I suppose they're being merciful to Titan by delaying this taking (or un-squatting Titan from its driveway), it was always a little unclear) for as long as possible

- on the CR side, they're putting the final fabric-and-stone dressing on the earth slopes atop the retaining wall paralle to Burget Ave and Charnwood Rd.


- At both Ball Sq and Tufts/College they've dug down to the "platform-and-elevator footings" level and are starting to build up the stations (they're still below grade, though)
 

Arlington

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^ It looks very much on schedule for a March 2021 opening of Lechmere and USq, (or am I deluding myself)
To me it looks like
Aug viaduct posts and spans
Sep month of viaduct floor & drains
Oct month of ballast
Nov month of ties
Dec a month of OCS rigging & signals
Jan a month of OCS connection & integration
Feb a month of Testing
Open March 2021?
 

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