Crazy Transit Pitches

[The EGE]

No, Needham conversion is a necessity no matter what. West Roxbury and Needham desperately need the frequency, and the line is always going to have an outsized impact on NEC operations. Inbound Needham trains either have to run on the west track - thus effectively turning the Southwest Corridor into a two-track line for Amtrak + Providence + Franklin + Stoughton (and heavily limiting Needham frequency) - or they have to cross over at Forest Hills and block other traffic.

The Highland Branch wouldn't be the right choice for the Blue Line regardless. Past Brookline Village, there's not that much density - it's mostly small village centers save for the Cleveland Circle area, which is also served by the B and C. It does great as a light rail line, and there's simply not the population to need heavy rail. All the other western possibilities - Allston, Brighton, Watertown, Waltham, and the north part of Newton - have much more population and all-day demand possible.

You have to convert every station - not just building high platforms, but a lot of crossover bridges to replace the current crossings - and find a new Green Line yard and maintenance facility to replace Riverside. All that cost and disruption, for what? Brookline and Newton don't have a significant improvement in their service, they lose direct North Station service, and trade Copley for a station further from the High Spine. Needham gets nothing. The only real win - elimination of a transfer to Longwood and Brookline Village - is equally achievable with D-E connector and Blue to Brookline Village, and it's pretty minor anyway.

 

[F-Line to Dudley]

On a different note, though I spend a good amount of time outlining why such extensions would be challenging, I personally find an extension to Watertown the most promising, at least on a 100-year timescale. It would require a generation of advocacy. Moreover, I think it is even further down the road than "Phase 2", as I believe that an intermodal West Station, with transfers to circumferential service and regional rail, would itself be a logical "second phase" destination point, in that it would provide valuable service, would still leave options open for the future, and would potentially be a modestly low-impact build.

I believe that @Charlie_mta has put forth proposals for a largely-elevated ROW between West Station and Watertown Square, and while obviously very expensive, I do think it's a compelling proposal, but again, on a 100-year timescale. I do think building further to Waltham is hard to imagine, in any century. And, as I outline in the post, I believe a better alternative to serve Watertown is a combination of LRT and Regional Rail. I could also envision an elevated extension along the Mass Pike to a major transfer center at Newton Corner; replace the Boston Landing commuter rail station with a Blue Line stop, and then add extra stops at Blue Line-spacing at Market St, Parsons St and Bigelow St, and allow Regional Rail service to run express between Newton Corner and West Station. I like both of these ideas, but I also don't think either of them is a surefire winner. Better to lay the groundwork with extensions to Kenmore or maybe West Station, and add Regional Rail service, and see where that lands us first.

The easiest way to build to Watertown is probably tunneling under the B&A to Newton Corner, then turning north in a Galen St. tunnel to the Square and unifying the awkwardly async NC+H2O bus hubs into true load-bearing West Region last-mile feeders. The B&A doesn't have utility relocation or a utilities sandwich layer like any under-street alignment would. You could essentially make it a miles-long Wellington tunnel with the bare tunnel roof functioning as the replacement Worcester Line trackbed and nicely wide-open construction windows to blitz it since the staging of the trench is all right-lane closures on the Pike and some sliding-scale pain threshold of temporary Commuter Rail/Amtrak disruption. And then Galen, while being a conventional (if mercifully short) street cut-and-cover, already features the live ex-A Line 600V DC feeder trunk running underneath it (currently used as a B Line-to-71 power interconnect). You'd save some considerable cash on BLX's substation construction by glomming off the existing power interconnects on the corridor and boosting some pre-existing 600V subs on the system instead of building at least one wholly new substation on a greenfield alignment.

Excludes Newtonville-Auburndale but would functionally re-create the densest majority of the "Riverside 2" rapid transit line from the 1945 BTC map, shotgunned onto the densest outside-of-Boston portion of the ex-A Line. And pitched that way...not quite so "Crazy"-sounding a cleanroom pitch because of the liberal appropriating of well-trodden study & prior-service ground. I agree you probably ain't ever getting direct to Waltham from there because of myraid technical challenges and middling intervening density, but for what NC+H2O would do overall for West Region bus connectivity Waltham might not truly need to be a link on that specific chain (plus Waltham can always be GLX'd as a 6-min. frequency branch out of Porter when Regional Rail isn't enough for them).

 

[luobo]

My crazy Blue Line tinker de jour has been to branch it at Kenmore in two directions: 1) Watertown via West Station, Harvard, Mt Auburn Hospital, and Arsenal; 2) Neponset via LMA, Jamaicaway (eating the tail end of the E), Arborway, Forest Hills, Morton St, and Gallivan.

Neither of these branches would likely necessitate full HRT capacity, but they would both fit half-HRT capacity pretty well.

 

[F-Line to Dudley]

My crazy Blue Line tinker de jour has been to branch it at Kenmore in two directions: 1) Watertown via West Station, Harvard, Mt Auburn Hospital, and Arsenal; 2) Neponset via LMA, Jamaicaway (eating the tail end of the E), Arborway, Forest Hills, Morton St, and Gallivan.

Neither of these branches would likely necessitate full HRT capacity, but they would both fit half-HRT capacity pretty well.

Harvard's already covered by the Urban Ring spur from BU Bridge-Harvard Square via West proposed in the very real Urban Ring Major Investment Study...provided that Harvard U. keeps its stated promise to reserve dedicated ROW through its ultimate Beacon Park redevelopment so it can stay grade-separated. So that one doesn't really need any consideration for BLX, as it'll most likely be pre-existing as an Urban Ring LRT appendage taking mix/match patterns from Kenmore/BU or Kendall/Cambridge long before you're shovel-ready to BLX anything out here.

West becomes a superduper transfer station in that universe if BLX-via-B&A to Watertown has a behind-prepayment transfer to Green Line-attached UR service as well as Worcester Line Regional Rail.

 

[Teban54]

That all being said -- if we want to talk about truly crazy transit pitches, imagine what a Blue-to-LMA extension would set you up for. Kenmore to LMA to Roxbury Crossing to Nubian to Newmarket to Seaport to Logan to Airport to Chelsea to Everett to Wellington. (Yes, I made a map of this, yes, it is ridiculous, yes, I will post it at some point. I named the file "Project Blue Lace", to rhyme with "shoelace" because the Blue Line looping back on itself looks a bit like a shoelace. Yes, I was way too happy with myself for the pun.)

Reminds me of this "blue" line in Singapore:

 

[Riverside]

It's unfortunate that the Needham Line's best replacement option effectively precludes the option of HRT on the Highland Branch, at least without screwing over at least one of the other CR services. That said, if SCR Phase II gets killed off by Phase I collapsing under the weight of its born-brokenness, or if the Corps of Engineers never allows a solution to the lunatic trestle through the wetlands, might there be enough spare NEC capacity to keep the Needham Line and therefore permit Blue-to-Riverside? (I kind of doubt it, but someone might know more.)

In my opinion, if there ends up being excess capacity on the NEC (for whatever reason), it should be reallocated to regional rail services -- to Westwood/128, to Dedham/Norwood, and to Providence. For example, Franklin Line services (both commuter services past Walpole as well as higher-frequency services to Dedham and Norwood) will likely be the first to be rerouted off of the NEC, instead traveling via Fairmount. Excess NEC capacity could be used to route a greater number of those trains back on to the NEC, providing better access to Longwood and Back Bay. Hardly a must-have, but to me a more efficient use of the available resources.

I love it as a Crazy Transit Pitch, though it's bringing flashbacks of F-Line's epic dismantling of LRT tunneling for the southern half of the Urban Ring in the Green Line Reconfiguration thread. I'm guessing the same infeasibility and absurd cost would presumably apply to this pitch as well (but of course we don't need to bother as much with those considerations in this thread).

Fascinating post as usual, Riverside, I look forward to the conclusion of the series.

Oh yes, it's not so much a Crazy Transit Pitch as it is a Fever Dream Transit Pitch. I have a map, but I'm not even going to post it in this thread -- it'll go into the Fantasy T Maps thread instead. The costs would be tremendous, and if we were going to spend those monies, we would be much wiser to invest it in a modern LRT subway along the same corridor. (The other major downside -- to do the full "shoelace", you need to build a new transit tunnel across the Harbor, and it would be lunacy not to use that tunnel for service to downtown. An HRT tunnel that's being used for an Urban Ring South would largely preclude that possibility, or require a four-track tunnel. It looks cool, but isn't remotely justifiable or sensible.)

And thank you! I appreciate the words of support.

No, Needham conversion is a necessity no matter what. West Roxbury and Needham desperately need the frequency, and the line is always going to have an outsized impact on NEC operations. Inbound Needham trains either have to run on the west track - thus effectively turning the Southwest Corridor into a two-track line for Amtrak + Providence + Franklin + Stoughton (and heavily limiting Needham frequency) - or they have to cross over at Forest Hills and block other traffic.

The Highland Branch wouldn't be the right choice for the Blue Line regardless. Past Brookline Village, there's not that much density - it's mostly small village centers save for the Cleveland Circle area, which is also served by the B and C. It does great as a light rail line, and there's simply not the population to need heavy rail. All the other western possibilities - Allston, Brighton, Watertown, Waltham, and the north part of Newton - have much more population and all-day demand possible.

You have to convert every station - not just building high platforms, but a lot of crossover bridges to replace the current crossings - and find a new Green Line yard and maintenance facility to replace Riverside. All that cost and disruption, for what? Brookline and Newton don't have a significant improvement in their service, they lose direct North Station service, and trade Copley for a station further from the High Spine. Needham gets nothing. The only real win - elimination of a transfer to Longwood and Brookline Village - is equally achievable with D-E connector and Blue to Brookline Village, and it's pretty minor anyway.

+1 for your summary of the challenges the Needham poses for the tri-track NEC. One of my favorite games -- Transport Fever -- has a pretty rudimentary signaling system, but it still can be a useful simulator for gaming out -- pun slightly intended -- the design ramifications of the current track layout. The old Commuter Rail track chart is illustrative: south of Back Bay, the only crossovers are at the Plains interlocking just north of Forest Hills, which is why we get what you describe -- either a bidirectional single track operation for Needham, or a number of disruptive crossings.

While I'm a little less pessimistic about the prospect of heavy rail in southern Newton, I think you do a great job of outlining the additional costs and disruptions, and for modest benefits (at best) at that. For what it's worth, as I understand it, when the 1945 proposal was made to convert the Highland Loop to rapid transit, I believe it was imagined as light rail stock all around at that point. Which does reflect the density a bit better, as you point out.

@F-Line to Dudley, great to see you back. Yeah, I'm pretty agnostic about tunneling under the Pike versus elevating over it, or nearby streets; both options will be disruptive in different ways, so pick your poison. Yes, you are right that BLX-to-Watertown (and, one has to admit, there is poetry to the "Blue" Line going both under the ocean and to "Water"town) is a pretty good compromise between the 1945 proposals for the Red Line (to Arlington via East Watertown) and the B&A. It seems doable, but also easily two generations of projects away -- and to me, a much stronger case after we see Green-to-Watertown and proper rapid transit frequencies to Newton Corner demonstrating significant demand.

@luobo, splitting Blue at Kenmore was something I went back and forth about when writing this series. In my opinion, Kenmore is too close to the core to branch a heavy rail line. (I actually think that JFK/UMass is also a bit too close to branch, but that's a topic for another time.) I don't know if you saw my previous post, but I describe Kenmore as being located at the "Inner Belt" of Greater Boston, similar to Sullivan, Kendall, or Ruggles, all of which I think would be unreasonable locations to introduce branching in their heavy rail lines. In particular, it's important to remember that Longwood is a major employment center, arguably on par with downtown. A new heavy rail line would see very strong ridership and would likely induce additional demand. If you are going to build a heavy rail subway, I think it's best to do it so it can be used for maximum effect.

@Teban54 -- good catch! I actually watched a video about the Singapore system just a couple of weeks ago, and learned about that line. Not exactly something I would intentionally design into my system, but certainly an interesting approach.

 

[dhawkins]

Crazy Extensions

1. Extend Blue line to Red Line at Charles, extend to Binney , elevated over Junction to Somerville, pick up test tracks, cross Mystic and run up the old Northern Strand Community Path (elevated) right of way to Lynn.

2. Extend Blue line to Lynn, elevated, connect in Lynn. Run along commuter rail through marsh. Use landfill area as a train yard.

3. Extend red line to Arlington - Lexington on abandon ROW / bike trail

4. Red line branch to Waltham, from Central down Western to Arsenal and pick up abandon Watertown branch of Fitchburg line out to Waltham

5. Extend Tufts green line to West Medford

6. Extend green line Heath down S. Huntington with one, one-way track loop thru Centre St, thru Bromley housing and loop back to Heath Station

7. Extend Orange line to Dedham on abandon Providence rail ROW, end in train yard at gravel pit behind Legacy Place.

8. Create Green line branch thru Needham Heights to Dover and loop back a branch to West Roxbury orange line.

 

[Brattle Loop]

1. Extend Blue line to Red Line at Charles, extend to Binney , elevated over Junction to Somerville, pick up test tracks, cross Mystic and run up the old Northern Strand Community Path (elevated) right of way to Lynn.

Pretty convoluted way of getting to Lynn. Hard to see what the benefits are that would outweigh the costs compared to the easier paths of extending north from Wonderland.

4. Red line branch to Waltham, from Central down Western to Arsenal and pick up abandon Watertown branch of Fitchburg line out to Waltham

Branching the Red Line south of the major transfer node at Harvard seems like it would be a bad idea. Attempting to branch at Central would probably be an engineering nightmare at that.

7. Extend Orange line to Dedham on abandon Providence rail ROW, end in train yard at gravel pit behind Legacy Place.

Uh, someone with better knowledge (F-Line?) might be able to answer more concretely, but isn't that ROW gone? I thought it was obliterated when Dedham let houses get built on it.

8. Create Green line branch thru Needham Heights to Dover and loop back a branch to West Roxbury orange line.

Green Line branch off the D to Needham's oft-discussed around here. Trying to branch that would probably result in pretty lousy service intervals on both lines. Moreover, there's no real need for the GL branch to cross the wetlands between the Needham end of its catchment area and the catchment of an Orange Line extension to W. Roxbury.

 

[HenryAlan]

Uh, someone with better knowledge (F-Line?) might be able to answer more concretely, but isn't that ROW gone? I thought it was obliterated when Dedham let houses get built on it.

Yes, it's partially built over. You can easily see it from Google maps satellite view, tracing it from behind the Star Market on Spring St., through the parking lot, then toward Dedham, but after a short distance, there is a block of new houses, and I think a new street, too, completely blocking the ROW, before it resumes again closer to the mall.

 

[Tallguy]

Yes, it's partially built over. You can easily see it from Google maps satellite view, tracing it from behind the Star Market on Spring St., through the parking lot, then toward Dedham, but after a short distance, there is a block of new houses, and I think a new street, too, completely blocking the ROW, before it resumes again closer to the mall.

About a dozen houses. 6-10 million if you wanted to eminent domain them

 

[KCasiglio]

About a dozen houses. 6-10 million if you wanted to eminent domain them

Really? That's a drop in the bucket of the GLX budget. If that's accurate why do people treat that RoW issue like it makes the project a non-starter

 

[Brattle Loop]

Really? That's a drop in the bucket of the GLX budget. If that's accurate why do people treat that RoW issue like it makes the project a non-starter

Probably because the politics of it would be disastrous. Eminent domaining houses to build a transit line is the kind of proposal that would get the NIMBYs screaming their heads off (are they still "NIMBYs" if it's more "Not In My Living Room"?) to the point of quite possibly upsetting the politicians (to say nothing of the fact that those houses even being there is inseparable from Dedham's, uh, less than fondness, historically anyway, towards public transportation).

 

[F-Line to Dudley]

Probably because the politics of it would be disastrous. Eminent domaining houses to build a transit line is the kind of proposal that would get the NIMBYs screaming their heads off (are they still "NIMBYs" if it's more "Not In My Living Room"?) to the point of quite possibly upsetting the politicians (to say nothing of the fact that those houses even being there is inseparable from Dedham's, uh, less than fondness, historically anyway, towards public transportation).

This. The deal, brokered in the mid-2000's by the Romney-era MassDOT was an unambiguous middle finger to the notion of ever building rapid transit there. It was done for the sole and explicit purpose of salting over a ROW that had been otherwise been legally landbanked since 1973 and totally unencroached...to make sure there was never so much as a study ever conducted on it again forevermore. Do you really think local politics is just going to roll over for an eminent domaining takeback? 6-10 chintzy single-family houses or not, they'll fight it to the ends of the earth over the 'principles' that led to that godawful deal being sought in the first place. It's absolutely a disqualifying problem.

 

[Tallguy]

Really? That's a drop in the bucket of the GLX budget. If that's accurate why do people treat that RoW issue like it makes the project a non-starter
[/QUOTE
As several have said, the politics suck.

 

[F-Line to Dudley]

As several have said, the politics suck.

It's also an intentional divide-and-conquer around the City line. Dedham being staunchly and consistently anti-transit means that OLX is going to have to bend to a VFW Parkway terminal station (on the 1911 Needham Cutoff ROW) rather than turn south on the Dedham Branch ROW, because if the park (ex-freight yard) by Dedham Center isn't available it's the only place with the land to place end-of-line storage and utility substation facilities. More unintentional transit for West Roxbury as direct cause-and-effect of Dedham wanting nothing to do with this. That's not a bargain Boston pols are going to trade in for political protestations of "Wait a minute! We need to hold up and save ourselves one less station because preservation of this delusional whole other town's best interests is paramount!" Like anyone with Boston-based political capital would ever take that line. So there's no mechanism for undoing encroachment to the Dedham ROW inside City of Boston because of that, or letting Boston act unilaterally in Dedham's best interest. Boston already gets everything it would ever want by Dedham not wanting this at all, and is quite happy with that fact.

 

[Scalziand]

Using the same argument, could you say that Dover also did W Roxbury a favor by ripping up their tracks so the Needham line would have no prospect for extension, making it a prime target for wholesale conversion to rapid transit?

 

[F-Line to Dudley]

Using the same argument, could you say that Dover also did W Roxbury a favor by ripping up their tracks so the Needham line would have no prospect for extension, making it a prime target for wholesale conversion to rapid transit?

Not really. Dover NIMBY's are a pain in the ass for sure, but they followed the approved process to get their 99-year, fully-revokable trail lease on a service-defunct ROW and have not physically encroached on it. Totally fair play to them. Millis CR restoration was always a longshot, even in spite of the state paying for a full 1996 restoration study workup. The towns on the corridor were very small, the protected corridor was truncated to only Millis and not anywhere usefully further, and despite producing pretty decent projected ridership for their sizes the cost per new rider was going to be intrinsically very high for that build. The NEC's traffic problems were fully foreseen by the time Amtrak was scaling up its ambitions in the late-90's, OLX had the long-term study history clearly demonstrating a greater good in terms of project priority, and any compromise scheme of doing OLX+CR on a widened 3-track ROW was going to be self-defeatingly expensive. But despite all that, it's still legally and functionally provisioned at the century level as a transportation asset in case something unforeseen comes up that compels us to change the usage back...so the landbank "works" as intended.

The business with the W.Rox-Dedham parcel sales was slimy politics through and through. A corridor that was sleeping 3 decades into a legal landbank was uprooted for the sole sake of uprooting it forever and making it impossible to ever plan something different. It highlights a critical flaw in that a rogue MassDOT administration could come in and sabotage banked assets on-the-sly without adequate public oversight if it were so motivated. I don't know *who* specifically had enough of a jones for killing this ROW >15 years ago that they spun that corrupt bargain, but they ended up totally getting away with it. It's now fractured in a way that can't plausibly be pieced back together again.

 

[Riverside]

A little bit late this week, but the "series finale" for Extending the T's Blue Line west is now live. I have more things in the works, but probably will take a week or so off before the next one.

In this post, I make the case in favor of the Kenmore alignment, largely from the perspective of overall network design. I think this discussion reveals a number of interesting esoteric points about the way the MBTA network functions, and is why I see this as more than just a question of “Kenmore ridership” vs “Kendall ridership” (though I absolutely think that there needs to be a formal study, and I will certainly change my opinions based on the results of such studies).

I spend a long time winding my way through the different topics here, but in one of my last paragraphs, I think I get to The Big Point I’m trying to make:

One hundred years ago, the mainline gateway to Boston’s western suburbs was located in the Fenway at Brookline Junction station. Despite all that has happened in the intervening century, the ROWs that were laid out feeding into that junction have persisted over all these years. Because of that, Kenmore has remained a transit nexus, and remains the strongest “launchpoint” for any future expansion to the west.

(The more things change, the more they stay the same.)

The other Big Idea I introduce here (which will be the topic of further posts at a later date) is a three-tier distinction between “light metro”, “heavy metro”, and “regional metro”. I think the terms “light rail” and “heavy rail” remain useful in certain ways, but also can confuse more than clarify. MUNI Metro streetcars are famously slow (~8 mph on average), operate in mixed traffic, and have numerous stops that are literally just straight up in the middle of the street; LA Metro’s E Line (formerly Expo Line) operates in a dedicated ROW at near 20 mph on average, with full length high platforms for level boarding. These services should not be placed in the same category.

Likewise, if we all get our Indigo wishes, and see EMUs running 7.5 min headways on the Fairmount Line, that is basically mid-frequency heavy rail in almost everything but name. Moreover, heresy though it may be to say, the reality is that certain corridors – particularly circumferential service and radial service outside of an urban core – can be as well-served by true, high-quality BRT as by LRT (and in some cases, even better), with virtually indistinguishable rider experiences between the two.

The terms “light metro,” “heavy metro”, and “regional metro” are meant to give us more precise terms to describe the capabilities and roles of different services, deemphasizing a rapidly antiquating distinction between “light rail” and “heavy rail”.

Once we start viewing the T as three overlaid networks (plus a fourth layer of local feeder networks – i.e. most buses), the gap at Kenmore becomes obvious and we can start to plan a more balanced and efficient system for the decades ahead.

 

[bakgwailo]

About a dozen houses. 6-10 million if you wanted to eminent domain them

Really? I count about 24, plus a bunch of backyards getting chopped back. And that only gets you to the old Dedham Mall. I have no idea how you really get passed that dead end to end up at Legacy place, but it seems like a lot of commercial takings, too.

 

[Brattle Loop]

In this post, I make the case in favor of the Kenmore alignment, largely from the perspective of overall network design. I think this discussion reveals a number of interesting esoteric points about the way the MBTA network functions, and is why I see this as more than just a question of “Kenmore ridership” vs “Kendall ridership” (though I absolutely think that there needs to be a formal study, and I will certainly change my opinions based on the results of such studies).

Another fascinating post, kudos again to you for the dedication you've shown to the topic, Riverside. I'm entirely in agreement you, both in terms of preferred destination and, more importantly, in the need to consider the network impacts as much as (or even more than) just the ridership potential at the chosen node-station.

Kenmore was once actively intended as a transfer node, hence the existence of the turnback loop (which I like to think of as the nameless, less-squeaky western counterpart of my namesake at Government Center); as I understand it the plan at one point was for the C (this predating the Highland Branch's conversion to the D-branch) to loop at Kenmore while the B's tracks would be eaten by the HRT-ified Central Subway. (Ironically, or perhaps poetically, given the clearances in the Tremont Street Subway, it might well have ended up using Blue Line-size HRT stock.) So there's a very good historical argument that Kenmore was supposed to be a LRT/HRT (light/heavy metro) transfer node and that the system's simply been suffering from its never having been built all these years, and that Blue (albeit now via Riverbank) would fix the problem that was intended to have been fixed last century.

The other Big Idea I introduce here (which will be the topic of further posts at a later date) is a three-tier distinction between “light metro”, “heavy metro”, and “regional metro”. I think the terms “light rail” and “heavy rail” remain useful in certain ways, but also can confuse more than clarify. MUNI Metro streetcars are famously slow (~8 mph on average), operate in mixed traffic, and have numerous stops that are literally just straight up in the middle of the street; LA Metro’s E Line (formerly Expo Line) operates in a dedicated ROW at near 20 mph on average, with full length high platforms for level boarding. These services should not be placed in the same category.

I look forward to these future posts. That said, while I'm intrigued by the three-tier concept, I do have a few thoughts. One's sort-of a nitpick, which is that I wouldn't call things like MUNI Metro's streetcars, New Orleans' streetcars (much as I like them), or even the surface-running portion of the E-branch as proper light rail, regardless of equipment. I wonder if there's room for either stratifying the classification between the systems operating in significantly mixed-modes (like with street running, which is really not that far off from BRT) and those that aren't. The Green Line's an interesting example, because a fair number of its problems come from mixing pure grade-separated LRT (D and the Central Subway), two and a half surface branches running in reservations, and half of a branch street running (resulting in the nasty garbage-in, garbage-out difficulty of scheduling the thing to work in the de facto HRT role the Central Subway has been pressed into). (MUNI Metro has some of the same characteristics with its subway, right down to being the other poor fools to suffer the lemons that were the Boeing LRVs.)

The other point is that as useful as tiered classifications are for discussions like this in forums like this (even if reasonable people can quibble about the specific definitions), part of me really, really hopes that your tiers don't catch on widely, because I feel like they're ripe for misunderstanding and misuse by moronic politicians who'd happily pick up the "light metro" definition to plaster over the fact that they're building BRT when they should be building LRT. (I can just see the MBTA of the era using "light metro" for the Silver Line just to try and add a bit more lipstick to that particular pig.) Hopefully that's just me being unnecessarily cynical, though

Likewise, if we all get our Indigo wishes, and see EMUs running 7.5 min headways on the Fairmount Line, that is basically mid-frequency heavy rail in almost everything but name. Moreover, heresy though it may be to say, the reality is that certain corridors – particularly circumferential service and radial service outside of an urban core – can be as well-served by true, high-quality BRT as by LRT (and in some cases, even better), with virtually indistinguishable rider experiences between the two.

Both of these are excellent points. I think BRT tends to raise a lot of ire around here because of our politicians' nasty habit of trying to use it to solve all problems (and not even doing it correctly when they have). You correctly identify that it's a tool in the transit arsenal, and it should absolutely be used when it is the best fit (like the southern half of the Urban Ring, per F-Line's exhaustive analysis of the excruciating difficulty of attempting to shiv LRT in there).

The terms “light metro,” “heavy metro”, and “regional metro” are meant to give us more precise terms to describe the capabilities and roles of different services, deemphasizing a rapidly antiquating distinction between “light rail” and “heavy rail”.

Once we start viewing the T as three overlaid networks (plus a fourth layer of local feeder networks – i.e. most buses), the gap at Kenmore becomes obvious and we can start to plan a more balanced and efficient system for the decades ahead.

Here's where I'd push back a little, referencing what I mentioned above. I don't know that I'd necessarily agree that the Green Line from Kenmore-east is as easily classifiable outside of the heavy metro network as it is west of Kenmore. It's certainly being relied upon to do the work of a heavy metro spine, the stop spacing is not that much more dense than the Orange Line, and on a whole it operates far more like a heavy metro than it does BRT; even one of the most significant differences, the vehicles, will be altered by the Type 10s. (Though, as above, that may well all be able to be chalked up to the Green Line being a unicorn hybrid; that it is such a unicorn is, in my view, a very good reason for some of the pressure to be taken off by BLX to Kenmore.)