Green Line Extension to Medford & Union Sq

vanshnookenraggen

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I see that the stations all have space for future platform extensions... except for Lechmere. Or am I missing something there?
 

FitchburgLine

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I see that the stations all have space for future platform extensions... except for Lechmere. Or am I missing something there?
The platform is U/C as 4 Type 7/8 cars long. But none of this will matter since the new GL cars will be 2/225’ and so the extensions to 300’ will never make sense
 

Wonk

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Presentation posted with lots of progress pics and not much else honestly
Does slide 10 imply that moving the CR to its permanent side of the ROW is now at least a full year behind their performance goal date of this month? If not, have they announced how far behind schedule that milestone has fallen? I imagine that is a GLX critical path item that would delay the entire project.
 

whittle

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Does slide 10 imply that moving the CR to its permanent side of the ROW is now at least a full year behind their performance goal date of this month?
I see absolutely no reason to make that inference based any part of this presentation.

I think it will make more sense if you ignore slide 9 (it's a repeat of slide 7).
 

jlichyen

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The Union Square design on slide 9 is marked as "draft - for discussion only" but am I understanding the station entrance design properly in thinking that in its current shape, it will block the outbound track from expansion westward?

Then again, I took another look at the trackbed westward and is it even wide enough for four tracks?
 

Charlie_mta

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The Union Square design......will block the outbound track from expansion westward?
Then again, I took another look at the trackbed westward and is it even wide enough for four tracks?
I've always had the same concern about the Union Square station design blocking westward Green Line extension. It absolutely has to be designed to allow that.

As for 4 track space west of the station, the only pinch point is at Porter Square which I think could be solved through a short tunnel underneath the commuter tracks there.
 

Arlington

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I've always had the same concern about the Union Square station design blocking westward Green Line extension. It absolutely has to be designed to allow that.

As for 4 track space west of the station, the only pinch point is at Porter Square which I think could be solved through a short tunnel and/or shifting all the tracks south just east of Mass Ave for a short stretch.
It seems to me that they set themselves up for going west of Union Sq but given other considerations did not build the northern track "ready to go onward"

Instead, as you can see from pages 8 & 9 of the Station Final Design boards, they did a reasonable job:
1) Station entry is via a full width plaza and access to a center platform. They did build this plaza and a 1-story accessory structure (employee bathrooms for shift/rotation use) that are "in the way" but they didn't stack anything elaborate on it. When going onward, they're going to have to re-do the entrance and tie it into prospect st differently. The "elevator by others" that does tie U2 into the Prospect St overpass is only half-future proof: I believe the point is that the overpass itself isn't future-proofed enough to be worth tying into.

Prospect St Bridge, The (existing) Electrical Substation,

2) Getting under Prospect St s the next big obstacle. Google Earth view suggests it has just two track berths, so there isn't clearance for the GLX to go under it, and that going onward was always going to require demolishing and rebuilding Prospect St bridge. As part of that rebuilding, a new entrance on that end was going to be called for, I'm guessing

3) There *is* a big electrical substation *directly* in the path of the future extension. That'd have to get moved anyway. In discussions here, we've thought they have space (immediately to the north of the current substation) but it didn't have to be moved for the USq station, so they didn't touch it.

Seems like they thought ahead for:

4) Webster-Newton bridge is also pinched underneath, but it looks like they've lined up the GLX to be able to fit under the existing bridge (which seems to have just barely 4 tracks worth of clearance under)
 
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F-Line to Dudley

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Westward extension involves punching through the Prospect St. bridge retaining wall (which is just packed with loose fill everywhere away from the deck joints) and framing the hole with an archway for each track berth. Fairly simple and inexpensive maneuver. They've repeatedly given that explanation at past community meetings about the provisions for further extension, and nothing has changed in years with the track layout at Union so they still intersect the wall at a spot the state guarantees can be punched through.

The electrical sub equipment does encroach on the property line, but Eversource has a lot of slack space on that site so the 2 existing transformers can probably be lifted up in-situ with heavy equipment, dropped further back, and re-connected. Eversource would have to rearrange them that exact way regardless if they ever wanted to expand the sub's generating capacity with addition of a third transformer, so the capability to move them within site footprint is eminently there already.

Webster Ave. is probably fine, but that's a bridge in dire need of complete and total replacement because of the severe weight restriction slapped on it. So they'll either carve out more breathing room if/when it's replaced as a solo MassHighway project or just lump in the bridge replacement with the Porter extension. Either way it'll get done in the next 20 years with all necessary space provisioning because the whole block-spanning structure is way too shot and substandard to attempt to repair in-place. Washington St. (1982 span) is tight but OK, Dane St. and Beacon St. bridges better-than-OK on width. And of course you get into Porter-proper with a shallow duck-under tunnel right after Beacon that slides under the CR tracks and whose roof forms the new CR trackbed.
 

jbray

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Instead, as you can see from pages 8 & 9 of the Station Final Design boards, they did a reasonable job:
This isn't related to Arlington's post, but the walkshed on Magoun Square found in the presentation is wrong. The residential to the left of the station is connected in a couple of places to the community path most importantly at Warwick st. Also, pedestrians are going to be able to walk through the development. Anyone living from Cedar St North of the path to the station will be able to easily walk.

Is there something they know that makes their walkshed map "true"?
 

ceo

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I noticed that too, when that map was on display at the community meeting. Looking at it closely, it appears that whatever software they used to generate it only considered publicly-accessible roads; it completely ignores the community path and the west entrance to Maxwell's Green (which is closed to vehicles). And clearly it didn't get proofed by someone familiar with the area, even though someone highlighted the community path.
 

kjdonovan

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Remember that red flag from back in August? “Count us as very worried,” Fiscal and Management Control Board Chair Joseph Aiello said after a project update yesterday, in reference to the board. “It would be really, really, really damaging to not keep this project on schedule. "

From my non-technical perch, I read that concern was that the track shift was supposed to be completed by September but had slid to November. There was a lot of anxiety because you can't shift the tracks in very cold weather so they were racing to finish work on the north side of the corridor before winter. Well, we are nearly halfway through December and the tracks have definitely not shifted--and there's no evidence that they will by the end of the year. Still lots (like more than a month's-worth) of drainage and retaining wall/sound barrier construction on the north side of the corridor.

Was there another delay because of the conditions or weather, etc.? Is this no longer as much of an existential threat?
 

BostonUrbEx

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From what I hear, instead of building a new track for the full length of the realignment, and then throwing over the end connections for the track throw to go off in a single weekend, they will now instead be doing individual sections of track throw every weekend.
 

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