Green Line Extension Lechmere to Medford

The old GLX site had all of the proposed maintenance facility locations including the one that was settled upon, but I can't find it at the moment. So I drew an extremely rough map. "Seacost Distillers" has already relocated.

TODAY (MON OCT 22) is the deadline to support GLX Phase 2 (U-Haul, Boston Ave @ Mystic Valley Parkway)
Please submit a comment that keeps GLX Phase 2 in the 5-year-plan "Doing" bucket--
rather than the "Planning" or "Dreaming" (where it has been relegated in the draft)

https://www.mbtafocus40.com/focus40thep ... wtocomment" onclick="window.open(this.href);return false;

They’ve done a bunch of grading and leveling of the Union Square site, and much of the ROW.

Looks like work has started in earnest on the Union Square branch. In the last few weeks, a bunch more piles of ties have been staged at the lot, the station area has huge piles of fill, the ROW has more gravel work done, and just this past Wednesday they moved the piling drill into the area ready to start work.

Question about the GLX.

Does anyone know what train patters might look like. For example, will all trains run past Park Street once it goes online?

Or will they have new line letters and routes that just run on the new extension?

Epsilon wrote:Well as I recall there are supposed to be two extensions, one to Union Square and one to West Medford... My guess is that the C and E will be through-routed... though it might make sense to send all the C/E to West Medford and the D/B to Union Square, which would add a lot more service to the north end of the line. (Would probably require a new car order, though)

They have plenty of type 9s coming with type 10s in design phase

Everything so far has indicated that the D Branch will be extended to College Avenue and the E Branch to Union Square, and that they will use those letters on both sides of Park Street. D and E are the clear through-running choices because they'll serve demand from the northside branches direct to the LMA. My thesis research indicates that running C and D to College Avenue will probably be necessary if ridership exceeds projections even by small margins.

I suspect you'll also see rearrangement of the downtown termini - re-extending the B to Government Center is almost certainly necessary - but that's something that you'll probably see discussed ~6 months before opening. With the through-running trains having less capacity to handle passengers from North Station and Government Center (mostly Back Bay-bound in the AM and reverse in the PM) you'll need the B and C to cover those better. (Ridership between Park Street and Copley is currently almost the same in both directions at rush hour.)

All the branches are every 6 minutes at rush hour, right? That's every 1m30s in the Central Subway.

That would be really exciting to get both the D and the C out to College Ave (not just the D): A train every 3 minutes would be noticeably more frequent than anything Wellington & Sullivan are likely to get right? Even better than bus connections to the Red at Alewife & Davis*

I'd expect a lot of bus riders to rise up and demand that at least some buses at Alewife (eg 67 & 350) & Davis (eg 87 88) and other "NW quadrant" buses like the 350, 134, 325 & 326 get tied to the GLX.

If that happens, I'd expect a virtuous cycle of frequency -> ridership -> multimodal trips (bus & bike) -> political support for the extension to Boston Ave @ Mystic Valley Parkway.

(For comparison: Red is every 4m30s and Orange is every 6m right now at peak. With new signals and CRRC fleets what would the headways be? 4m-ish? 5m-ish?)

I think Red is targeting 3 minute headways (6 minute on the branches), orange is 4:30.

RenegadeMonster wrote:Question about the GLX.

Does anyone know what train patters might look like. For example, will all trains run past Park Street once it goes online?

Or will they have new line letters and routes that just run on the new extension?

I can't remember exactly where the info is (so many different websites and project restarts at this point) but I recall the idea being that the D and the E will extend along the two new branches and the B and C will continue to run as they do now.

Once this project goes online because of increased frequencies there will likely be increased ridership. Increased ridership will mean that we will see increased demand and support for further expansion projects. This will mean that the Green Line can go even further to the North, and the Orange Line, and the Red Line.

The next $1B to be spent is already being dialed in: onn the so-called Green Line Transformation (GLT), which is the Type 10 (longer, bigger, 3-car-equivalent train) and modifications to the infrastructure to support it (shaving the walls, eliminating tight loops, upgrading trackside power). MBTA just declined its option on the Type 9, which implies they're going full-speed toward "doing" the Type 10 and GLT.

Lots of great links here
https://willbrownsberger.com/a-new-visi ... reen-line/" onclick="window.open(this.href);return false;
If you're into loop-radius porn:
https://cdn.mbta.com/sites/default/file ... dicies.pdf" onclick="window.open(this.href);return false;

Beyond that, yes, pressure will build for Extending the D/C from College Ave to Mystic Valley Parkway and extending the E from Union to Porter Sq or Alewife/Waverly.

But also note that the Orange at 5min headways is going to be a superpower, and communities along the Blue & Orange are going to demand their turn: BL to Lynn, OL to Roslindale & Needham. If it cleans up nice enough, Melrose may even deign to see it extended to Reading.

Arlington wrote:Beyond that, yes, pressure will build for Extending the D/C from College Ave to Mystic Valley Parkway and extending the E from Union to Porter Sq or Alewife/Waverly.

But also note that the Orange at 5min headways is going to be a superpower, and communities along the Blue & Orange are going to demand their turn: BL to Lynn, OL to Roslindale & Needham. If it cleans up nice enough, Melrose may even deign to see it extended to Reading.

I'd say that anywhere within the red circle on this map could support at least Green Line (Light Rail) service if not subway service (Red, Blue, Orange).

Arlington wrote:The next $1B to be spent is already being dialed in: onn the so-called Green Line Transformation (GLT), which is the Type 10 (longer, bigger, 3-car-equivalent train) and modifications to the infrastructure to support it (shaving the walls, eliminating tight loops, upgrading trackside power). MBTA just declined its option on the Type 9, which implies they're going full-speed toward "doing" the Type 10 and GLT.

Hi All - am new to the board. Cambridge resident and daily red line commuter.

Just wondering wouldn't adding CBTC to the central subway do a ton more for capacity than buying bigger cars? Especially if copley-Gov Ct is running 1.5minute effective headways during all of rush hour.. the current block/manual signaling just seems to back everything up and cause bunching. I read this study on how NYC's 2nd avenue subway's underwhelming ridership suggests that adding CBTC to the 6/5/4 trains would add much more useful capacity for 10% of the cost.

I don't understand signaling technology well enough to understand how to install CBTC on just a portion of the line, and aware that the green's branches are a dispatching nightmare.. but wondering if this is feasible or even being remotely considered.

CBTC (or any kind of ATC) would not increase capacity in the Central Subway in its current condition. It would have other benefits - including likely an increase in speeds, and certainly in safety - but 40-45 TPH is about the fundamental limit for light rail regardless of human or computer operation. Muni's ATC system (Seltrac) can theoretically handle 60 TPH on their similar-to-the-Green-Line system, but in practice it struggles with 35-40 TPH. And that's with true level boarding and 4 doors on each side of the cars.

Both Muni and the MBTA struggle with the surface branch lines being extremely unreliable, which results in severe bunching in the subway segments. You can't run a reliable subway when your branchline trains are coming in 2 or 3 or 4 in a row, with highly variable passenger loads. Aggressive signal priority, some stop consolidation, and (in particular) headway management at the terminals are needed to corral the branches into behaving better.

Maxing out TPH in the Central Subway also requires a lot of other improvements before CBTC might make a difference. True level boarding (which will hopefully be happening with the Type 10s) will reduce dwell times. Slow zones and unnecessary stops need to be eliminated, and some curves modified. Copley Junction desperately needs to be converted to a flying junction. The current AVI system which identifies trains and sets switches needs a more reliable replacement. The electrical system badly needs upgrades. Once you're doing all of those things, then it's worth looking to see if CBTC can make the subway more reliable and/or more frequent.

Longer trains are the only way to achieve the massive capacity increase needed for the GLX (20% of current ridership, and more if it exceeds the very conservative projections) and the next several decades (20-40% increase). By 2030, you need 40 TPH with 200-foot trains (triples of current cars, or two 100-foot cars) just to have crowding be no worse than current. Longer vehicles are cheaper per person-capacity than shorter vehicles.