Proposal: Massive Green Line overhaul

(Sorry this is so long. Its an idea I've been thinking about for a while now, so it requires a lot of..... words.)

The Green Line is in sad shape. It carries 204,800 people on an average day (FY '04) on what is basically a glorified nineteenth-century trolley line. Though the transit world has seen countless improvements in the century since the opening of the Tremont Street Subway, the Green Line has seen few of those advances. The LRV's that serve the line today are arguably just bigger streetcars. The signaling system offers only a slight improvement in safety and efficiency over the ones in place at the turn of the century. And the capacity and speed of the system is severely limited by the small size of LRV's, awkward boardings, bunching of trains, and stops in much too close proximity to each other (at least on the surface).

So what to do? The T says that upgrading the signals, while improving safety, would also decrease system capacity. The T also says that they can not run any more trains through the Central Subway. Adding a third car to all train sets would help somewhat, but only at a huge extra cost of personnel and maintenance, and it would still have the awkward boardings which slow trips.

Seems like we're in a bad spot. So I propose throwing the whole thing out.

Too many people are served by the Green Line to keep it as a light rail system. We need to stop kidding ourselves about this. It serves (almost) as many people as the Red Line, which is heavy rail with large six-car train sets. The time has come to convert the Green Line to heavy rail.

Already I can hear the screams coming.

The tunnels are too tight for heavy rail! Yes, in some spots. Mostly (in my entirely unscientific reasoning) the problems would be between Haymarket and Arlington. It would require some very big changes in a few areas. The one big sticking point seems to be the turn at Boylston station. Well, why not just adjust the tunnel trajectory in such a way that the curve is less extreme? It seems to me that it should be very possible to tunnel under the Boston Common and make the turn a little more friendly (and less screech inducing).

Now heres another way to make it easier to fit heavy rail into those tunnels. Use Blue Line sized cars. Those puppies were already designed for tight turns, since they have to operate in a former streetcar tunnel (sound familiar?) and along an old narrow gauge railroad. Sure, they won't be able to make the Boylston curve, but they will be fine at many other places where Red Line or even Orange Line equipment would have serious trouble. The Green and Blue Line could even share equipment, maintenance facilities, personnel, and track.

Excuse me? Share track? Yeah, why not? I would propose building a new incline at/near Government Center and Park Street. At this incline the Blue Line would join the Green Line tracks and continue past Government Center to Park Street and beyond! Other cities have major heavy rail lines share track, heck we even do it with the Red Line branches. I think it could be done.

It would likely necessitate large train sets. I'm talking 8-12 cars for peak service. New stations should be built to accommodate at least 10 cars. My own (again, unscientific) estimations put rush hour headways at approximately 6 minutes per branch, 3 minutes for the shared sections.

Oh yeah, what about the branches? How would you handle that? A good question, and probably the one that will tick off the most people. I am proposing a two branch system that would replace the existing Blue and Green Lines. I would actually propose keeping the existing coloring scheme, though modified of course.
The Blue Line would stretch from Lynn (or Wonderland or Salem or Beverly or Maine or whatever it takes to make you feel all warm and tingly) to Government Center, meet up with the existing Green Line ROW to Park Street all the way down to Kenmore. From Kenmore it would surface and go west following the existing Riverside “D Line” ROW, making most (but probably not all) of the existing stops along the way.

The Green Line would stretch from West Medford (or Lechmere or Union Square or Vermont, again whatever makes you feel good) following the current Green Line alignment to Kenmore Square. At Kenmore, it would continue on in a new tunnel under Commonwealth Avenue to at least Packards Corner. After that point, it gets a little more tricky. Although I would really like to continue on in a tunnel under Comm Ave all the way to Boston College, I suspect that the costs would be much too prohibitive. One alternative I've thought about is a mostly surface running, grade separated ROW in the existing B Line ROW. Grade crossings would be closed, or the tracks could be elevated or tunneled over the roadway. Under no circumstances would I support the die hard rail fans wet dream of an elevated structure over Comm Ave. It would seem prudent however, to use a viaduct or tunnels in some places. Another (more cost effective?) option might be to give these bad boys pantograph's and let them have a limited number of grade crossings. Most crossings would still be closed however. Also note, that I would not support having third rail power along with grade crossings as is apparently done in Chicago (and shown in a recent thread here). Something tells me the residents would agree.

I've barely touched on construction at this point. As I mentioned, some tunnels would have to be reconstructed. But there is also the need for third rail installation (most likely), new signals, possibly new track, and new platforms. Its the later that will be the most difficult. Simply put, I don't have an easy answer for building new platforms, but I'll throw out a few ideas.

Alright, lets start with the basics for upgrading the existing Central Subway stations. Given that my plan would use 8-12 car trains, and given how close together many of the stations are, I figure we could sacrifice a few stations. Keeping the biggies, like Park and North Station are givens. Theoretically we could do away with Haymarket (redundant to have two transfer points to the Orange Line) and Government Center (redundant since Blue and Green now meet @ Park), though I'm not sure if we should give them up since it will reduce crowding from other stations. Its worth thinking about to save costs though. These stations could be consolidated: Boylston/Arlington, Copley/Hines.

There are a few benefits to consolidation. Obviously, travel time will be decreased. Also, since the new stations would be so much larger there would be less walking distance between them. And heres the big one. If we only build a few stations in between existing stations, it will simplify construction, reducing costs, and... allow existing Green Line service to continue (mostly) uninterrupted. I think so anyways.

Another option would be something akin to how New York rebuilds its stations. Shutdown one side of the station so that service is available only in one direction. If someone wants to go the other direction, they ride the train 1-2 stops the wrong way and switch sides. Not sure if this is the best idea. Very unsure when you start talking about consolidating stops.

A third and (significantly) crazier idea is to lay temporary tracks on the streets of Boston. Man wouldn't that be fun? Shutdown Tremont & Boylston Streets and there you go. Don't think this would go over too well with the public, not to mention it would be slow, quite possibly the most expensive way to do it, and wasteful since the tracks would be pulled up at the end of construction. Plus theres the ADA to consider.

As for along the existing B & D lines, well it would be easier. For one thing you could bustitute the lines during construction if necessary. (I know, booooooooo!) Obviously, you are going to do massive consolidation along the B line. In places, 3-4 stops could easily be reduced to just 1. (I'm looking at you Blandford, BU East & BU Central!) Most of the D line stops would stay, though we could probably spare a few. And yes, all the stops would have Charlie card gates.

Hmmmm... I feel like I'm forgetting some tiny little detail... Oh right! The C & E lines! How silly of me. Well, sorry to say, they don't warrant upgrading to heavy rail. So, we've got two options. Either keep them as light rail lines, but don't run them all the way to downtown, or bustitute them. Yeah, that last option doesn't sit too well with me either.

So lets keep em as LRT, and in mainly the same shape they are in right now. We could do the simple thing and keep them terminating at Kenmore and Copley, but what fun is that? Lets do something fancy.

Start at the E Line southern end (Heath, Arborway/Forest Hill, Providence RI, whatever). Follow that up into its existing portal at Northeaster. Once underground, take a left turn under Massachusetts Ave to Comm Ave, then tunnel under Comm Ave to Kenmore Sq station and out through the existing St. Mary's portal to Cleveland Circle. You could build a new station near Berkley. With some clever engineering, you might be able to rebuild Kenmore in such a way as to allow cross platform transfers to the Green and Blue lines like the North Station “Super station.” At the very least you could make it a simple flight of stairs/escalator. And feel free to give this line a color if you like. Might I suggest, teal, a combination of blue and green?

The new Mass Ave tunnel could even have the tracks paved over so that buses could use the tunnel as well. Well, with a few new portals at least. Maybe it could eventually serve as a tunnel for a LRT service to replace the #1 bus. (Urban Ring?)

Heres an idea to further enhance the new service. Give the new Green and Blue lines (former B&D) short tunnels, that would take them out to the vicinity of Cleveland Circle. From an underground station there, riders could transfer to the “Teal Line” and “Teal Line” riders could also connect to the Blue and Green. More interestingly, Blue and Green riders could connect way out in Brookline, further reducing the radial nature of the T as it currently is. Excluding the proposed Urban Ring, it would be the only MBTA subway-subway transfer in suburbia.

So, sounds simple right? I mean if we live in a city that can get the Big Dig done on time and under budget, this should be easy as pie... crap...

But seriously, am I way off base here? I welcome all critiques and honest criticisms, except those of the ”OMG LOL THIS W1L NEVAR HAPIN!!!!!!!!!!!!!!!!!1” variety. I know its a long shot, but at some point every big project seems impossible. Maybe if we start thinking about what to do about the Green Line today, we can actually accomplish something (not necessarily this) within 30-50 years.

So. Who has a better idea? Or, who has a few extra million dollars lying around to draw up a study for this?

P.S. Yes, I realize this would likely cost at MINIMUM $4-5 Billion.[/i]

I'm no subway expert, but I do live on the B line. I think light rail is very well suited to above-ground travel. There is a certain "charm" to having trolleys rolling down Comm Ave, Beacon St, and Huntington Ave. I would not want any of it to be replaced with heavy rail. What I would like to see is fewer road crossings, fewer stops, and traffic signals that favor trolleys.

With apologies to Michael Calcagno of nycsubway.org, who made the original version of this map, I've edited his MBTA track map to show my idea for a Blue Line conversion of (most of) the Central Subway.

The Blue line at Bowdoin would be extended in a tunnel southerly on Bowdoin Street, then under the east wing of the State House in a deep bore tunnel, then underneath Park Street to the Park St. Station, where it would occupy the westerly two tracks of the station.

The Blue Line cars would then go to a reconfigured Boylston station, and then head west in the existing Green Line tunnel, but with the sharp curve at the outbound side of Bosylston sta. widened to accomodate Blue Line cars.

The Green Line would head south from Boylston, utilizing the aboandoned Tremont Street tunnel, surfacing in a new portal at Marginal Street next to the Mass Pike, then continuing on the surface of Washington Street to Dudley Sq.

The existing Green Line branches B and C would remain light rail, but truncated where they meet the converted Blue Line at Kenmore station. The E line could be rerouted in either a new Stuart Street tunnel, or follow surface streets alongside the Mass Pike, to join the new Dudley Square Green Line branch.

I'm just wondering if you have ever seen this website: http://www.vanshnookenraggen.com/FutureT/ He has all sorts of mbta fantasies and cool maps of what the T could look like if they had unlimited cash flow and no annoying NIMBYs.

Charliemta wrote:With apologies to Michael Calcagno of nycsubway.org, who made the original version of this map, I've edited his MBTA track map to show my idea for a Blue Line conversion of (most of) the Central Subway.

The Blue line at Bowdoin would be extended in a tunnel southerly on Bowdoin Street, then under the east wing of the State House in a deep bore tunnel, then underneath Park Street to the Park St. Station, where it would occupy the westerly two tracks of the station.

The Blue Line cars would then go to a reconfigured Boylston station, and then head west in the existing Green Line tunnel, but with the sharp curve at the outbound side of Bosylston sta. widened to accomodate Blue Line cars.

The Green Line would head south from Boylston, utilizing the aboandoned Tremont Street tunnel, surfacing in a new portal at Marginal Street next to the Mass Pike, then continuing on the surface of Washington Street to Dudley Sq.

The existing Green Line branches B and C would remain light rail, but truncated where they meet the converted Blue Line at Kenmore station. The E line could be rerouted in either a new Stuart Street tunnel, or follow surface streets alongside the Mass Pike, to join the new Dudley Square Green Line branch.

While the Riverside D Branch is the perfect candidate for Blue Line Conversion, citing it's location, and widths, no tight curves at the D branch. That would be nice if the D became a Blue Line Operation, although the platforms would have to be raised to 6 X 48.5 feet to accommodate six-car Blue Line trains.

There are all kinds of proposals out there for linking up the blue and green lines. I've seen one that proposed a blue line running parrallel to the Bolyston Street subway along the Charles - crossing under Kenmore and picking up the Riverside branch. Then, I think my friend actually got the idea of extending the Blue line through the West End, picking up the viaduct at Science Park through Lechmere and up to Medford put into Access Boston 2000-2010.

Go to the Transportation Library on Stuart Street - there are all kinds of plans and interesting documents there. I even found initial 10% design drawings for the Stuart Subway (linking the E line with the Tremont Street stub to avoid the at-grade crossing of the E-line with the other lines south of Copley) from the 50s!

danib62 wrote:I'm just wondering if you have ever seen this website: http://www.vanshnookenraggen.com/FutureT/ He has all sorts of mbta fantasies and cool maps of what the T could look like if they had unlimited cash flow and no annoying NIMBYs.

Oh man, I love that site

Alot of far fetched fantasy on there.

vanshnookenraggen wrote:

danib62 wrote:I'm just wondering if you have ever seen this website: http://www.vanshnookenraggen.com/FutureT/ He has all sorts of mbta fantasies and cool maps of what the T could look like if they had unlimited cash flow and no annoying NIMBYs.

Oh man, I love that site

Any chance you can draw up a map that includes this most recent proposal?

You know, everything seems like it would work well, and Im for any extention of the blue line, but the residents on cambridge street are complaining about an extension down the street to Charles MGH, which is a straight shot, nevermind tunneling under there buildings!

But if that could be overcome (Maybe post - N-S rail link, when we have a TBM or two to use, to get it done quickly) its a great idea, as the green line could still be preserved, at the same time reducing the traffic in the central subway, and using heavy rail to boot!

Rather than these fantasy proposals that will never happen, why not look at some simpler possibilities.

The capacity problem could be resolved by adding more cars. Right now that is impractical as each car requires its own operator. The operator is there to operate the doors and collect fares. If we switched to an honor system using ticket machines outside of the subway as San Diego and most European cities use with roving inspectors that eliminates the fare collection. The cars should be set up so the operator in the first car operates the doors. After all if a conductor or guard can operate the doors on a 6 car subway train why not on the trolleys?

Once this was done you could operate at least 4 car trains - may have to enlarge some platforms. Also the T would need additional equipment but that is a lot cheaper than digging tunnels.

Just my 2 cents and it won't get done either.

jonnhrr wrote:Rather than these fantasy proposals that will never happen, why not look at some simpler possibilities.

The capacity problem could be resolved by adding more cars. Right now that is impractical as each car requires its own operator. The operator is there to operate the doors and collect fares. If we switched to an honor system using ticket machines outside of the subway as San Diego and most European cities use with roving inspectors that eliminates the fare collection. The cars should be set up so the operator in the first car operates the doors. After all if a conductor or guard can operate the doors on a 6 car subway train why not on the trolleys?

Once this was done you could operate at least 4 car trains - may have to enlarge some platforms. Also the T would need additional equipment but that is a lot cheaper than digging tunnels.

Just my 2 cents and it won't get done either.

I agree 100%. Infact I don't think upgrading the Green Line to heavy rail would be a good thing.
If any tunnels should be built it should be a new one between Park and GC to allow better headway and smother opperations. This was a proposal back in the 40's and should still be considered.

Anything that is messing with Park Street, Boylston and in between won't happen because they are national landmarks.

That's not entirely true. Not long ago I saw some renderings for the modifications proposed to Boylston Station as part of Silver Line Phase III, and they were extensive. The existing platforms were to be relocated, and the tracks and portals leading to the abandoned Tremont Street tunnel were to be eliminated and blocked off to make room for the new bus tunnel underneath.

If they can reconfigure the Boylston Sta. for Silverline Phase III, then they could also do it for a Blue Line conversion.

I think there are some smaller-scale things that would work. . .


The obvious and inexpensive. . .

-- Signal priority on the B, C, and E. For Pete's sake, this is such a no-brainer...JUST DO IT ALREADY! That alone would save God knows how many trains from getting backed up.

-- Through service on the Park St. inner inbound track. Thankfully the crossover upgrades are already budgeted so trains can bypass the loop in a couple years. That track has been wasted capacity for too long, especially now that no lines have terminated there permanently for 20 years. Lechmere/North Station cars and GC cars should be separated at Park St. Since through cars stop further out on the GC platform than looped cars, those Lechmeres and North Stations need to be waved ahead to keep proper headways. I think that'll help a lot.

-- General signal upgrades. Even a teensy bit of automation is better than an 1897-era inspector-controlled traffic system that falls prey to human error. Not talking ATO or anything like that, but jeez wouldn't a little GPS technology and some computers really help out with headway management? If it's good enough for the Silver Line, it ought to be good enough for the Green Line.

-- Connecting tracks from the E at the Huntington/South Huntington intersection to the D at Brookline Village. A couple-blocks of street-running on Route 9, and a cut down a side street. I'm not thinking so much as a real revenue-generating alternate route, but the Copley-to-Kenmore end of the subway has no redundancy and a shutdown like the '96 flood would absolutely paralyze the system. There needs to be an alternate through routing to the subway for emergencies, especially when the northern extensions start happening. You could at least run through Boston College, D, and E service in the event of disaster...have a lot more options for non-revenue moves...and could even run some special routings, say, on Marathon Monday (where it would really help) or other types of limited service. Minimal impact to Route 9 because these tracks will mostly be idle a la Chestnut Hill Ave., but I think it's an investment that'll pay for itself the next time the T has to do paralysis-level bustituttion on the Central Subway. Aside from the Red Line from Park-JFK that portion of the Green Line is the portion of the system with the least redundancy in the event of catastrophic disruption.


Infrastructure upgrades (non-radical, but costing significant $$$). . .

-- Elimination of the Copley junction. No Green Line routing can ever hope to imitate a real rapid transit line when every single train has to get funneled through that bottleneck from hell. Seriously now. The 1897-construction planners had the foresight to build ahead-of-their-time flyovers on 2 portions of the Tremont St. tunnel and also do a nice non-invasive incline on the original Huntington Ave. branch-off point...but their band-aid solution decades later for branching off the new Huntington Ave. was almost amateurish in its lack of traffic management foresight. Everything backs up on that linchpin, and there's nothing they can do to fix the whole left-turn across traffic fiasco without a lot of cash. Gonna have to be done someday. I propose recycling the old Boylston St. incline where the rerailer currently sits, constructing a quick dive-under tunnel that shifts the E tracks left/south immediately on the other side of the wall, continue it running parallel to Arlington (skipping the station but leaving a provision for platforms and connection to the current fare lobby if demand calls for it), peeling off across Copley Square to join up at a real Back Bay Green Line station connected to the Orange Line/Commuter Rail/Bus lobby, and then joining back up to the existing Huntington Ave. subway right when the line curves into Prudential Station. I'd then leave the old Copley Junction tracks intact as equipment and disabled train storage (much more convenient than where the rerailer LRV is currently stored). This would eliminate that cursed junction for good and give the E a MAJOR capacity boost with the smoother junction to the main line and a MAJOR ridership boost with a full-service Back Bay stop while taking a massive load off those tiny stations in the Boylston St. tunnel. Really, Back Bay is such a major transit hub it deserves a full Green Line stop and not an over-long pedestrian tunnel to an antiquated station like Copley. And it would make transfers a lot more efficient by concentrating all the Main Line Orange/Blue/Red/Silver/E connections on the Haymarket-to-Boylston axis instead of having that weird transfer point halfway out (and weirder inbound because you have to ride further out of your way to get back out on the B/C/D). I think they'd have to build a new platform-to-platform connector at Boylston to make transfers efficient, but since it used to have one that's possible. Only complications are that a parallel tunnel along the Arlington corridor might affect some adjacent building basements along Boylston St., so it might have to dip at a lower level in parts. And also Prudential station becomes kind of useless if you've got a high-capacity Back Bay stop...although since it's already unmanned there really wouldn't be much pressure to abandon a redundant stop.

-- Smooth out the Boylston curves. This becomes a bigger problem if that Back Bay/junction tunnel ever happens because then you've got a need for real rapid-transit level service and lots of ridership on the E. Since the sharp curve happens after the station and after the Tremont Tunnel overpass, the tunnel work required would be more-or-less confined to the walls of the Boylston St. tunnel without affecting historic Boylston Station. That might make the historical impact easier to handle. Really, that's a stupid reason anyway to maintain such a bottleneck on the system. Just scrape away some tunnel wall after the substations and round it out. It can still be a tight curve. It just shouldn't be a hard right-hand turn that you have to almost stop in order to make safely. That one's gonna suck if Boylston becomes a big Silver/F Line or even E-Line transfer stop. Trains need to be able to clear it at an acceptably moving speed instead of stopping almost cold. I'd also advocate for smoothing out the "jolt" on the edge of the inbound platform next to the inspector's booth when the 4-track section starts. Because the first train has to pull into that nook to stop they have to proceed very slowly. If Boylston's going to be a busier transfer point they have to get trains in and out of there faster. Might have some historical impact, but I think they should rework that inspector's area of the island and rework a center support beam or two around the crossover so that's a smoother merge.

-- 4-track the Park-to-GC tunnel. We've already got 4-track capacity from Haymarket to GC, through Park to Boylston outbound, and Boylston-to-Park inbound (with through service once the loop crossover construction starts on the inner track). That's a lot of valuable 4-track capacity in some very old tunnel that except for Park outbound and the eastbound Brattle Loop just isn't being used (and never has been since the Tremont and Lechmere feeder lines all went away). The reason for that is that congested 2-track stretch between the two busiest stations in the system. If you ride that stretch you know how the trains get backed up end-to-end inbound. Invasive or not that's such a pinch point in the system I think they've got to 4-track it and widen the tunnel walls at some point. Separate all the lines out coming out of Boylston into Park, and keep 'em that way as they sort through the Brattle Loop and separate out the Lechmere/Union Square, North Station, or West Medford destinations on the merge back into Haymarket. And on the trip into Park don't let all the GC-looped trains impede the flow of anything coming from beyond. Huge infrastructure cost and GC station would have to have its track and platform alignment extensively modified, but I think it's got to be done as a rapid transit nod. There's just too much congestion on that stretch and the T is not making good use of the 4-track capacity that already exists because it's not connected contiguously. Linking those core transfer stations all together with 4-track capacity will do wonders for traffic flow and give the subway a capacity boost for extensions at both ends.



Extensions (nothing too fanciful, but each brand-new route has large costs attached)...

-- West Medford and Arborway. Duh. Stop bellyaching and honor the transit commitments. West Medford's a no-brainer, but even Arborway can be mitigated by some of the other things I list like signal priority. Downtown JP delays won't hurt anyone if you can keep the reservation and Heath short-turns running smoothly and get those damn 39 busses out of mixed traffic, especially on the part of the route that's already duplicated with subway and reservation service.

-- Boston College express service via Chestnut Hill Ave. (no street-running stops) and the D line, providing a subset of rush-hour service. The street-running portion won't be a picnic to navigate, but with only 2 traffic lights and no stops it won't be that big a drag. The big thing is lightening the load on most of the B-line and significantly reducing the number of stops it takes to get from BC to downtown.

-- Extending Blandford St. pocket track as 3rd express track to Packard's Corner. If BU and some city planners get their way Comm Ave. is going to be completely reconstructed to Packard's Corner with one fewer through traffic lane a la the downtown portion of the street. That means the reservation is going to get a little breathing room for minor expansion and probably some trees. I think the T should do a bi-directional track and run limited rush hour service on it to Packard's Corner a la the 57 limited bus to speed through some of the "BU School Bus" stops. This express track would've been an even better idea if the A line trackage were still available because then you could run local service on A's and expresses on B's...but I think the express track could be useful even with only the B.

-- Dudley Square via Tremont Tunnel with subway stop at NE Medical Ctr. Nobody's saying a trolley line on Washington St. is the MOST efficient possible transit. The El was, but the El isnt coming back. LRV conversion is better replacement transit than a bus, and a more natural fit for a one-seat downtown ride than even a scaled back SL Phase III. With signal priority and saner traffic law enforcement in that corridor it can work well and at less cost than anything that would make the Silver Line function as well as a real rail line. It's such a short route and it would link into the 4-track portion of the system so the headway disruption potential is probably even less than what we're used to daily on the B-line. That Boylston junction is very smartly-designed for traffic flow and transfers. It's not the Copley/E nightmare at all.

-- Porter Square via proposed Union Square alignment, with 1-2 intermediate stations along Somerville Ave. Only question here is whether you can fit it all next to the Fitchburg Line CR tracks, but if so this is a no-brainer. Union Square is already going to happen, Somerville Ave. is a heavily-populated corridor, the Red Line badly needs a northern bypass and quicker Cambridge route to North Station (especially if Red ever gets extended to Arlington Center). Porter's also a nice intermodal transfer point with Red Line, CR, TT's, and bus lines all converging within easy walking distance to Davis as well. I propose cramming in the tracks as best as possible on the ROW and then for the last several hundred feet cutting under Somerville Ave. in a tunnel and meeting underground with some stub-end tracks connected to the fare collection area.

-- Urban Ring light rail routes. Electrification of Grand Junction route via Lechmere with some sort of Brighton/A-line sorta-replacement service making use of the CR tracks ROW and possibly terminating in Harvard Square via a Charles River crossing tunnel that either recycles a portion of the abandoned Red Line Eliot Shops tunnel for the last leg and/or links up in mixed traffic into the bus/TT/old-trolley tunnel for transfers in the station. Don't have a real route map in mind, but the T can recycle a lot of ROW for this. Would give MIT a much-needed couple of stops and easy transfer to BU, serve a heavily-populated and transit-starved area of Brighton, and tie Harvard's exploding Allston campus into its Harvard Square headquarters. Another option is the long-imagined rail replacement for the 66 bus, which I don't have a clue how to pull off.