Green Line Extension to Medford & Union Sq

I may have missed this being shared in here but the Lowell line is being shut down all week at all hours this week to allow for some GLX drainage work.

Reducing schedule risks:
• Install two (2) critical cross-track drainage lines
beneath Tufts Interlocking in Medford
• Reduces schedule risk to achieving on-time revenue
service on the GLX Medford Branch

They expect to save about $2 million by doing this. I must say this project being managed almost entirely outside of the MBTA is being handled so so much better than the ones they directly oversee.
 
I'm having a hard time imagining what this bridge(Washington St bridge) is going to look like underneath when they are finished. I can see where the sidewalks are going to go, but what is this secondary looking abutments underneath for? In my opinion, they completely missed the opportunity to widen this underpass so the lanes dont squeeze from 2 to 1 and back to 2 again on the other side. They also could have widened the sidewalks and included a nice wide bike path. Anyone care to explain what I'm looking at?
MVIMG_20200517_170941.jpg

MVIMG_20200517_170947.jpg
 
In my opinion, they completely missed the opportunity to widen this underpass so the lanes dont squeeze from 2 to 1 and back to 2 again on the other side.

It’s possible that we’re not seeing the whole picture because this underpass is also in scope of the McGrath grounding... if that ever happens.
 
Those secondary abutments are temporary. See Street View here for an earlier pic of the construction staging when west half of the bridge was new and east half was old. And then here from the other side in slightly earlier view from when the old bridge was chopped in half but the west-half new span had yet had to have its permanent abutments poured.

The new-pour concrete conjoined to the old stone blocks appears to be some sort of construction staging platform, as you can see from the first Street View it was ramped-up with rock ballast that's now mostly been scooped away. Those, along with the now-disused old stone abutments from the west half of the old bridge, should be removed pretty soon. Resulting undergrade width will then be about 1/3 wider than the old span and 2 ft. taller.
 
Those secondary abutments are temporary. See Street View here for an earlier pic of the construction staging when west half of the bridge was new and east half was old. And then here from the other side in slightly earlier view from when the old bridge was chopped in half but the west-half new span had yet had to have its permanent abutments poured.

The new-pour concrete conjoined to the old stone blocks appears to be some sort of construction staging platform, as you can see from the first Street View it was ramped-up with rock ballast that's now mostly been scooped away. Those, along with the now-disused old stone abutments from the west half of the old bridge, should be removed pretty soon. Resulting undergrade width will then be about 1/3 wider than the old span and 2 ft. taller.

Got it! Makes sense now. The sidewalk will be quite wide, that's great!
 
Also they need a level platform to sit on. Most of the drilled shafts on the southwest side of the corridor are getting installed through what is an existing slope. Imagine a right triangle - and trying to drill straight down while you're perched on its hypotenuse at a 45 degree angle.
Oh, that's a good point. So they build up the berm, install the pilings and then dig away the berm and the existing slope. Clever. I assume the pilings do an OK job holding back the soil before the concrete panels are installed.
 
Oh, that's a good point. So they build up the berm, install the pilings and then dig away the berm and the existing slope. Clever. I assume the pilings do an OK job holding back the soil before the concrete panels are installed.

As they excavate away the berm they also install temporary lagging (appears to be welded wire and shotcrete) between the piles on the way down to track grade, then the permanent precast panels are installed later.
 
next time i think i see you i'm just gonna yell "javier!" and see if the photographer turns around. for reference (and so as not to scare you), i'd be the skinhead walking the min-pin and holding a thermos of "coffee" -- usually around the HS/city hall/winter hill area, but sometimes union, ball, magoun, or inman square (or, more rarely, central).

great pix as usual btw.
 
Hi Crisbrat, I haven’t seen anyone with those descriptions yet but if We run into each other I will definitely say Hello.
 
^ If they had gone with vertical concrete abutment walls under the right-side end of the bridge instead of what appears to be sloped embankments underneath, they could have fit in a hell of a lot more roadway/sidewalk.bike lane width than what they'll have, for a small amount of additional cost. Maybe they'll scoop all that crap out and end up with a vertical wall there. That's what they have on the left side.
 
I've never been so excited about being totally inconvenienced by the T closing a station...


Lechmere Station salvage signage should be appearing on the T gifts website later in the year. They always make that stuff available because people will kill each other for the collectibles. Would imagine Science Park is also going to get completely re-signed during the shutdown for consistency with the "brightening" program's latest-gen wayfinding graphics going up elsewhere on the system, so watch for souvenirs from that stop to show up online in-tandem with Old Lechmere.
 
As much as we complain about no red-blue, blue-lynn...etc, rightfully so, this is still a huge deal that the green line is getting a major grade separated expansion like this. These dont come around every day. Im very excited to see if this can spur some of those other projects once people see how successful this is because people havent seen a new transit line like this in decades. Cant wait to see this succeed massively.
 
As much as we complain about no red-blue, blue-lynn...etc, rightfully so, this is still a huge deal that the green line is getting a major grade separated expansion like this. These dont come around every day. Im very excited to see if this can spur some of those other projects once people see how successful this is because people havent seen a new transit line like this in decades. Cant wait to see this succeed massively.
I honestly think that the red-blue connector is a real possibility in the next ten or so years. Might be pushed back a bit because of how much corona has decreased revenue coming in.
 

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