MBTA Red Line / Blue Line Connector

[Brattle Loop]

I've always pictured a Cambridge Blue Line extension travelling under the Grand Junction ROW, then off to Allston along the Worcester line ROW

Somewhere (probably in the Crazy Transit Pitches thread, but I'm not sure) F-Line to Dudley has a pretty-thorough rundown of the infeasibility of tunneling under the Grand Junction, I'll link to it if I can find it. Short version is that there are some parts that would be extremely tricky to tunnel through if it's possible at all (a lot of it's built on fill near the river), and, even more problematically, you'd have to dig under the Red Line and expose it to a massive new climate-change-exacerbated flood risk it doesn't presently have. (I don't know if it's all as much of a dealbreaker as F-Line seems to think, but the ROW looks awfully tempting on a map without surface indications of some of the belowground treachery that would be involved.)

 

[HenryAlan]

I do recall the land fill issue, now that you mention it. But I think an elevated line above the ROW would also work just fine.

 

[Brattle Loop]

I do recall the land fill issue, now that you mention it. But I think an elevated line above the ROW would also work just fine.

I'd be fascinated to see an elevated line that could somehow fit through here. MIT's got a couple of different air rights buildings over the ROW that aren't moveable outside of Crazy Transit Pitches (if even there), and it's not likely to be easy to get approval for a new-installation HRT line (even if it's got overhead lines instead of third rail) with a grade crossing. Anything transit on the Grand Junction other than pure surface (which means bad scheduling and traffic impacts as CR, or otherwise making it LRT and probably part of the Green Line) is excruciatingly difficult if not outright impossible.

 

[Charlie_mta]

.... you'd have to dig under the Red Line....

Not necessary to dig under the Red Line where the GJ railroad crosses Main Street. The Blue Line could be tunneled under the Charles on the north side of the Longfellow Bridge, and then dip under the Red Line where the Red Line is still on the surface of Main Street near the western end of Longfellow Bridge, The rest of the tunneling for the Blue Line under the GJ rail line down to the Charles River in my opinion is doable with the proper design, pumps and ongoing dewatering.

 

[Brattle Loop]

Not necessary to dig under the Red Line where the GJ railroad crosses Main Street. The Blue Line could be tunneled under the Charles on the north side of the Longfellow Bridge, and then dip under the Red Line where the Red Line is still on the surface of Main Street near the western end of Longfellow Bridge, The rest of the tunneling for the Blue Line under the GJ rail line down to the Charles River in my opinion is doable with the proper design, pumps and ongoing dewatering.

Dip under and go where? Under all the MIT buildings?

Even if you can find some way to avoid directly abutting the Red Line itself, we're still talking about building a subway tunnel, largely in fill, in close proximity to a body of water with known poor future prospects for flood control. Active dewatering, just because of where it is and what it's built through, is going to jack the cost up, and that's just as a tunnel, it's worse if it ever touches the surface anywhere along the GJ south of Main Street.

The Grand Junction's a very tempting stretch of land to play with on a map, but in real life it's got a bunch of drawbacks. Moreover, what does a Blue Line subway from, essentially, Kendal to the BU bridge actually get you that you can't get from sending it on the much-easier side under Storrow via Kenmore? A one-seat ride to Kendall instead of the Charles transfer? It'll be a lot of money for that little bit of convenience, and a lot of difficulty.

They're interesting ideas, and worth debating, but I'd respectfully suggest that further discussion of them not directly related to the actual, apparently-revived-from-the-dead Red-Blue Connector be moved to their natural habitat in the Reasonable and/or Crazy Transit Pitches threads.

 

[Tallguy]

Is that the southwest extension 2 you outline here: https://www.vanshnookenraggen.com/_index/futurembta/theblueline/ ?

Does it make sense for red and blue to intersect at MGH and then again at Harvard?

The case for BL to Kendall is strong, but fizzles out after IMO

Dip under and go where? Under all the MIT buildings?

Even if you can find some way to avoid directly abutting the Red Line itself, we're still talking about building a subway tunnel, largely in fill, in close proximity to a body of water with known poor future prospects for flood control. Active dewatering, just because of where it is and what it's built through, is going to jack the cost up, and that's just as a tunnel, it's worse if it ever touches the surface anywhere along the GJ south of Main Street.

The Grand Junction's a very tempting stretch of land to play with on a map, but in real life it's got a bunch of drawbacks. Moreover, what does a Blue Line subway from, essentially, Kendal to the BU bridge actually get you that you can't get from sending it on the much-easier side under Storrow via Kenmore? A one-seat ride to Kendall instead of the Charles transfer? It'll be a lot of money for that little bit of convenience, and a lot of difficulty.

They're interesting ideas, and worth debating, but I'd respectfully suggest that further discussion of them not directly related to the actual, apparently-revived-from-the-dead Red-Blue Connector be moved to their natural habitat in the Reasonable and/or Crazy Transit Pitches threads.

GJs future is Light Rail. Its nearly all there right now

 

[Arlington]

the problem with a Grand Junction subway was that the Red Line is at a bad depth @ GJ

I have come to believe that new transit should only go to neighborhoods willing to to lots of TOD (preferably housing).

If you accept that as a principal, it makes it really hard to justify taking the blue line out to Kenmore, Because the Back Bay is not going to re-develop its self with density to match the new transit.

(also note that F-Line and I agreed that the yard stubs on the GL under North Station seem well suited to a GL riverfront if you really wanted to go that way)

 

[Tallguy]

the problem with a Grand Junction subway was that the Red Line is at a bad depth @ GJ

I have come to believe that new transit should only go to neighborhoods willing to to lots of TOD (preferably housing).

If you accept that as a principal, it makes it really hard to justify taking the blue line out to Kenmore, Because the Back Bay is not going to re-develop its self with density to match the new transit.

(also note that F-Line and I agreed that the yard stubs on the GL under North Station seem well suited to a GL riverfront if you really wanted to go that way)

I'm intrigued and a search gives me nothing.

 

[The EGE]

I have come to believe that new transit should only go to neighborhoods willing to to lots of TOD (preferably housing).

If you accept that as a principal, it makes it really hard to justify taking the blue line out to Kenmore, Because the Back Bay is not going to re-develop its self with density to match the new transit.

I'm in general agreement with the first part - infill stations and suburban extensions need to justify their cost by contributing to adding housing. However, I don't think that major TOD is necessarily needed to justify extensions into already dense, walkable areas. The GLX is a perfect example of that - Somerville already has sufficient residential density to need high-quality transit, and other than Union Square, there simply aren't that many parcels available for TOD. Similarly, I don't think it should rule out a riverbank subway. Even with the density deserts of parks and the Charles, any of the four plausible station sites (Hatch Shell, Dartmouth, Mass Ave, Kenmore) are already in some of the densest areas of the urban area. (Recent development near Kenmore arguably already counts as TOD.)

There aren't that many places where I could see new TOD offering substantial enough housing to tip the balance of transit construction priority. Triple deckers with a few higher buildings on urban street grids is already sufficient density to justify rapid transit. Maybe redev in West Lynn or West Roxbury could be enough to bring them to the top of the heap - but even then, they're both obviously valuable projects even at current density. A lot of the obviously redevelopable land (particularly that that wouldn't displace necessary functional uses) is already near good transit: the massive parking lots along Fort Point Channel, Suffolk Downs, Wonderland, Sullivan Square, Bayside.

 

[Plen-T-Pak]

I'd be fascinated to see an elevated line that could somehow fit through here. MIT's got a couple of different air rights buildings over the ROW that aren't moveable outside of Crazy Transit Pitches (if even there), and it's not likely to be easy to get approval for a new-installation HRT line (even if it's got overhead lines instead of third rail) with a grade crossing. Anything transit on the Grand Junction other than pure surface (which means bad scheduling and traffic impacts as CR, or otherwise making it LRT and probably part of the Green Line) is excruciatingly difficult if not outright impossible.

Then go down Vassar. Fuck em. No neighborhoods down that stretch and it's a no man's land after Mass Ave anyway. Only half serious but the idea of elevated Blue is intriguing. An elevated station at Mass Ave would turn that shitty intersection into something cool, like the Beachmont station that really ties the room together. Oh, and make Vassar bike only.

 

[Brattle Loop]

I'm in general agreement with the first part - infill stations and suburban extensions need to justify their cost by contributing to adding housing. However, I don't think that major TOD is necessarily needed to justify extensions into already dense, walkable areas. The GLX is a perfect example of that - Somerville already has sufficient residential density to need high-quality transit, and other than Union Square, there simply aren't that many parcels available for TOD. Similarly, I don't think it should rule out a riverbank subway. Even with the density deserts of parks and the Charles, any of the four plausible station sites (Hatch Shell, Dartmouth, Mass Ave, Kenmore) are already in some of the densest areas of the urban area. (Recent development near Kenmore arguably already counts as TOD.)

I'd have to go digging to find the discussions about Riverbank, but I didn't think there was much in the way of stations proposed as part of that project (maybe one infill before Kenmore?). Regardless, the point of that project was more about another spine that could relieve some of the load on the Green Line from Kenmore-Downtown along with provisioning the Blue Line for potential future extension if desired. (And in F-Line's discussion, the project was essentially a trade in, road-to-transit, contingent on cutting down Storrow to a normal road and re-using part of its tunnel and ROW for the subway and for improving the embankment along the Esplanade.)

 

[ceo]

I'm intrigued and a search gives me nothing.

Quite a while back, F-Line claimed that the center tracks of the North Station storage yard, in between the running tracks as they curve west to ascend to Science Park, were intentionally designed to provide for a future riverfront branch. I think he's flat-out wrong on this, the ramps for the running tracks converge as they exit the tunnel and it does not look to me like there's remotely enough room between them for two tracks to go through. Maybe it would work if you ramped down from further back in the tunnel, but I was never clear on what purpose such an extension would serve anyway.

 

[ceo]

And having said that, yes, we should be talking about the shambling reanimated corpse of the Red-Blue Connector on this thread. A thing I found particularly interesting is that they ruled out using a TBM because they'd have to grout the hell out of the soil in front of it and it would cause just about as much surface disruption as cut and cover. And also because a TBM makes no sense for a tunnel this short, of course.
I was a little surprised at the other two alternatives for the Charles/MGH station, where they close the existing surface entrance and build underground passageways from the sidewalks to a mezzanine. It means pedestrians no longer have to cross to the middle of Charles Circle, of course, but it'll make that nice pretty headhouse almost pointless.

 

[bigpicture7]

...we should be talking about the shambling reanimated corpse of the Red-Blue Connector on this thread.

^yes, so that's why I am replying with an idea relative to some of above on the crazy transit pitch thread here instead:
https://archboston.com/community/threads/crazy-transit-pitches.3664/post-415847

My idea relates to this:

The case for BL to Kendall is strong, but fizzles out after IMO
GJs future is Light Rail. Its nearly all there right now

 

[Equilibria]

Riverbank is, and always has been, a bad choice. I prefer sending it into Cambridge and this alternative would be perfect. Of course it's not preferred.

Regardless of any future extension, Alternative 3 should not be preferred. The MGH headhouse allows this station to serve far more density, particularly with Bowdoin closed.

 

[vanshnookenraggen]

Regardless of any future extension, Alternative 3 should not be preferred. The MGH headhouse allows this station to serve far more density, particularly with Bowdoin closed.

I agree entirely.

 

[Riverside]

After routinely hitting character limits here on the board, I've decided to start a blog. One of the first things I wanted to write was an overview of crayon proposals for extending the Blue Line past Charles/MGH, including some discussion of the hurdles to overcome, and what these proposals tell us about the MBTA network overall. As it happens, I actually wrote most of it before this latest round of Blue-Red Connector news, so I lucked out with having some timely content mostly ready to go.

The final piece is quite long (because of course it is), so I've broken it up into several parts. This first part, posted today, actually takes a look back in time at how the Green Line and Blue Line were originally conceived; I believe that the planning decisions made in the 1890s-1920s continue to have ramifications today, and provide valuable context for our discussions today. I'll try to post the follow-up parts on a roughly weekly basis going forward. Based on the discussion above, I think a number of folks here will find this series interesting.

Since I don't want to just be pushing people to my blog, I'll give a short summary of my post here -- if you are interested in more, please click on through!

Extending the T’s Blue Line west: Historical Background

Planning a "next step" extension of the Blue Line beyond Charles/MGH is difficult because, while there are many possibilities, none are obvious in the way that most other heavy rail extensions in Boston are. For example, while it's true that you could extend the Orange Line east from Oak Grove or Malden Center to the Saugus Branch ROW, the obvious choice is to extend it north toward Reading instead. There is no equivalent for Blue Line West.

I argue that this is because the Blue Line and Green Line (and their BERy predecessors) have acted like two halves of a single line for most of their history. The gap between the Red and the Orange Lines has been dominated by the Green Line for 100 years, filling in where we would otherwise expect an HRT radial line to go. This "2 halves of 1 line" concept is reinforced by early 20th century proposals that called for uniting the proto-Green Line and proto-Blue Line, with proposals varying over the years from a united streetcar network to a fully converted heavy rail subway (or two). These two lines were seen as siblings from the beginning.

The intervening century, however, has seen the Green Line grow into a subnetwork of its own. Indeed, I'd argue that we can conceptualize the Green Line's current capacity problems as a symptom of needing to "pretend" to be a heavy rail radial like the Blue Line. Due to the quirks of how the Green Line has developed, it no longer can be easily replaced by the Blue Line. Thus we are left with many possible options for Blue Line expansion beyond Charles/MGH, but no obvious winner.

 

[Arlington]

Congrats on hitting the character limits (I didn’t know we had any) best wishes on the blog and I hope you’ll keep cross posting

 

[bigpicture7]

...I hope you’ll keep cross posting

^ +1 on this. I enjoy your posts and will be more likely to check out your long-form work (in the busy-ness of life, etc) if you cross post it here.

 

[stick n move]

Hasnt the “obvious” route always been sending blue down the riverfront and replacing the green D branch with blue? F line always stated that if/when it happens you need to swap out storrow, but regardless thats been the generally accepted future of the line for a while.