Green Line Reconfiguration

[Brattle Loop]

Reliability: clear win for the Subway Alt on this one, as the Surface Alt will have twice as much street-running (even with dedicated lanes); but, the story is still a little more complicated because the Subway Alt will have to compete with a number of other routes in the subway -- if strategic turnbacks were included in the Surface Alt, there could be more flexibility to recover from delays; the Surface Alt would also be immune to any cascading delays on the rest of the LRT network

Fascinating post as usual, and I might go back and add more comments later once I've calmed downs from Bruins-induced irritation. Having experienced quite a few encounters with that atrocious intersection at Summer and the surface route where the South Station offramp comes up from the tunnel, I feel like it would be potentially nightmarish to try and run LRT through there, at least at rush hour. The degree to which that chunk of road gridlocks is nasty. Obviously there are ways to mitigate that to a degree, but I don't know that I love the idea of any project that plans a surface run through there given what I worry it would do to its reliability at peak times.

 

[Riverside]

Fascinating post as usual, and I might go back and add more comments later once I've calmed downs from Bruins-induced irritation. Having experienced quite a few encounters with that atrocious intersection at Summer and the surface route where the South Station offramp comes up from the tunnel, I feel like it would be potentially nightmarish to try and run LRT through there, at least at rush hour. The degree to which that chunk of road gridlocks is nasty. Obviously there are ways to mitigate that to a degree, but I don't know that I love the idea of any project that plans a surface run through there given what I worry it would do to its reliability at peak times.

Not to pre-empt your further comments by replying right away -- definitely keen to hear your additional thoughts! Yes, really the main question here is whether I've talked myself in circles such that I've lost sight of the obvious conclusion that surface streetcars are terribly unreliable, even with dedicated lanes; at the end of the day, this really does all come down to whether the reliability won't be so terrible as to ruin this idea on sight.

For what it's worth, I'm generally agnostic about the specific route through/around South Station. I wonder if the road network can be reconfigured at all to better clear the way for surface transit. I'm eyeballing stealing two lanes of Atlantic Ave for LRT lanes going in both directions, and converting one lane of Surface Road to go in the opposite direction, until you get to Summer St and then... yeah that gets gross.

Idk. #bancars

I should say, though, even setting this proposal aside, the vision for the T7 is a bus in each direction every 8 minutes through that intersection at rush hour. So someone will need to think of something at some point.

(Grasping at straws... I wonder what political will it would take to turn, say, Chauncy St and Arch St into transit malls? Eyeballed route in spoiler.)

Spoiler: Transitways everywhere

1) Washington
2) Washington + Essex / Kneeland + Harrison (one-way pair)
3) Chauncy transitway
4) DTX Red Line transfer
5) Chauncy transitway
6) Arch transitway
7) Arch + Milk / Franklin + Devonshire
8) Devonshire transitway
9) Stub-end at Old State House or loop Devonshire + Congress + Water

EDIT to add: I guess it's worth saying -- if you go back to The EGE's post that kickstarted this recent discussion about Green Line routes to Nubian, in that conversation he and I took for granted that potentially there wouldn't be any rail on Washington St if a subway via BUMC were built, and that it would be something like a T49 bus route instead. And the benefits I listed out above -- frequencies, homogeneity of running environment, etc -- those exist whether you have rail or bus on Washington St at surface level. Finding a way to incorporate both surface rail and a subway is somewhat necessary if the South End gets a streetcar first before a subway is subsequently built... but if Nubian <> Downtown is otherwise taken care of, I'm not sure that Washington St is screaming for surface LRT.

And if surface LRT does get built first... well (I say, preparing to duck behind my desk when the thrown rotten veggies start flying), you could just reroute it to South Station once the subway gets built and call it a day. Maybe you extend it to Longwood at the other end as a consolation. But, if not for Nubian, the Washington St corridor isn't necessarily all that different from Summer St in Southie, or Main St in Charlestown: a unique trio of routes that maintain a one-seat surface ride into downtown from about 2 miles out, and which have speedy rapid transit running from their outer hub with only limited local stops. (Southie is a less clean comparison here, though Andrew plays a vaguely similar functional role.)

(We could have fun over in Crazy Transit Pitches crayoning out a second LRT network, running through a new Congress St subway, with branches to Nubian, Southie, Chelsea and Charlestown, entirely separate from the Green Line.)

 

[Teban54]

Excellent post, @Riverside!

In my view, assuming a Nubian subway for both a GL branch and Urban Ring, this entire issue of Nubian and Washington St's transit needs is largely based on three questions, addressed in this exact order:

1. Nubian subway: Which street to go under? Washington, Harrison, or Albany?

This question has downstream implications affecting demand for a surface LRT/BRT route on Washington, even though Nubian subway and Washington service have different roles (the former primarily serving Nubian and possibly BUMC riders, the latter serving South End riders).

• A Nubian subway via Washington or Harrison will likely reduce the demand for local Washington service down to that of a regular bus route, due to significant walkshed overlaps.
• If Nubian subway is routed via Albany instead, Washington service may still merit LRT, as an Albany subway has no hope of serving South End.
• Albany subway's main advantage is lower cost, but how much lower is a question.

2. Washington St: LRT or BRT?

Two factors are relevant here:

a) Demand, which is heavily affected by Question 1. The EGE's comment earlier regarding Blue Hill Ave is relevant here:

Not a half measure - bus lanes are more useful than rail on BHA. They allow overlapping services (22, 28, 29, 31) which can run to different terminals for connections. Buses are faster than trains when running at street level, even in dedicated lanes. The only advantages of rail on a surface corridor are capacity (nah, 60-foot buses every 5-10 minutes are fine here) and ability to run onto off-street rights of way (nope - no use through-running with the Mattapan Line, and it's far too long a surface route to go into the subway).

b) Whether LRT infrastructure exists (i.e. whether a surface Nubian LRT is built before the Nubian subway), as Riverside alluded to above.

3. If LRT: Tremont St subway, or some surface route?

As Riverside discussed above. This question is obviously irrelevant for BRT.

The question of choosing the surface route (running via the Greenway or BNRD's Downtown Transitway, how to beat the traffic near South Station) comes as secondary to all three questions.



Much of the discussion here focused on Questions 2 and 3, so I wanted to point out the elephant in the room, Question 1. An Albany subway may be cheaper alone, but the additional (financial and political) cost of providing some service on Washington may outweigh the cost advantage, especially if Washington LRT is needed.

My own preferences are:

1. Harrison subway
2. BRT (aka "SL4/5" or "T49")
3. Either keep the BNRD SL4/5 route, or feed it as a southern branch of the Downtown Transitway ("Navy Line")

Of course, in a real-world scenario we may not even get past Question 1. Most likely, we'll get surface LRT to Nubian via Washington to replace SL4/5, and that's it.

 

[Brattle Loop]

X

This has gotten stuck in my mind. I'm less wild about Washington streetcars going straight into the Seaport subway; you lose the connection to the Orange Line, and this route is already transfer-poor.

Definitely. A forced transfer off of Washington effectively replicates (if not in quite as severe a form) the Silver Line's inbred inadequacy as an Elevated replacement; the lack of transfers. You'd get the Red Line, which is an improvement, but at the cost of a less-useful connection to the Green Line (feeding into Park gives access to everything, including the stuff that wouldn't ever touch Bay Village and its environs), and no connection to Blue, as well as the loss of the Orange connection already mentioned. I could conceivably see a Washington-Bay Village-Seaport service pattern as an option (either for events or as an overlay pattern on top of the more-frequent base Washington-Park route), but while it's operationally cleaner not to have to engage the Central Subway, there's a reason that shotgunning that service pattern didn't work before. The subpar transfers kill its ability to work as an integrated part of a network.

Parsimonious and higher frequencies for all: assuming a 30 tph limit between Park and GC (somewhat arbitrary but fine for now), removing the Washington streetcar from the mix means that you can see higher express frequencies to Nubian and potentially simpler frequencies across the system overall -- two potential distributions being:

• 15 tph to Park <> Huntington (then splitting among Riverside, Needham, Heath as you wish) and 15 tph on Park <> Nubian, giving you 4-min headways (which is probably the closest we've seen yet to "equal or better")
• 10 tph on Park <> Nubian, and then 10 tph each of two of the three Huntington branches (Riverside, Needham, Heath, with the third being picked up as a Seaport service)

Does it make a difference if the service doesn't reach GC? I don't love the idea of any specific route not hitting all the transfers (though the B did it for most of the past decade), but assuming sufficient overall throughput of cars between Park and GC, is there room for more frequencies Park-south if they're turning at Park and not hitting that bottleneck tunnel? Curious if that affects the calculations at all.

Beyond that, the next reason "why not" is that there simply aren't a lot of good alternatives. As mentioned above, running into the Seaport subway misses transfer opportunities, and also doesn't provide great access to downtown. Creating a new LRT subway branching north from South Station is a fun idea, but hard to justify for just one line (unless you wanted to convert the T7 and T111 to LRT as well, which becomes a Whole Nother Thing).

Crazy Transit Pitch: Congress Street Subway as the trunk of a new LRT network

Getting from Washington St to South Station is mostly doable: Washington <> Kneeland <> Greenway, all of which are wide enough that they could be reconfigured with center-running lanes (I think). Running along Washington up to Kneeland would give a good transfer to the Orange Line at Tufts Medical Center, and an okay transfer to the Green Line at its Bay Village Tremont platforms.

The space is there, but oh boy, as I mentioned earlier, the thought of those intersections is giving me nightmares. The highway ramps don't make life easy, and I'm not sure it'd even be possible to thread transit through the northwest corner of the Surface/Summer intersection. There's two lanes on the surface and two lanes coming up from the tunnel merging in a very small amount of space into three lanes (nominally). There's a little room to play with, but trying to thread even one track through there is going to screw over one of the surface (maybe an acceptable loss), the tunnel (probably not an acceptable loss systemically) or both, not to mention it'd probably be dangerous to have that much traffic with that ugly a set of intersections having LRT running through it. (Looking at the Google map, that side would have to be southbound, because otherwise you'd have a situation where an opposite-direction trolley was crossing in front of traffic coming up the highway ramp that might well not be expecting it.) I'd almost rather try and find a way to get it on Atlantic by Summer because that intersection's at least marginally more straightforward (if not necessarily any less of a potential graveyard for reliability at peak times).


Got distracted, more to follow (probably).

 

[Teban54]

(Grasping at straws... I wonder what political will it would take to turn, say, Chauncy St and Arch St into transit malls? Eyeballed route in spoiler.)

The redesign actually has SL5 use Chauncy St, though it's not clear whether there will be dedicated bus lanes:

(Inbound route via Washington St and Essex St is in lighter grey.)

An alternative to your proposal is to use the route above to South Station, then merge into the Downtown Transitway/T7.

Does it make a difference if the service doesn't reach GC? I don't love the idea of any specific route not hitting all the transfers (though the B did it for most of the past decade), but assuming sufficient overall throughput of cars between Park and GC, is there room for more frequencies Park-south if they're turning at Park and not hitting that bottleneck tunnel? Curious if that affects the calculations at all.

Don't you have to rebuild the outer loop at Park for Tremont branches to terminate at Park?

And even if you do that, it doesn't help with capacity on Tremont branches (Huntington/Nubian) at all. The bottleneck then becomes the outer tracks of Boylston-Park, which was already exactly the same as Park-GC (assuming all Central Subway branches use the inner tracks to turn at Park).

 

[Brattle Loop]

Don't you have to rebuild the outer loop at Park for Tremont branches to terminate at Park?

Not necessarily. There was once a crossover from the northbound/inbound Tremont wall track (current track 4) to the fence track (current track 3), which would allow access to the loop. I don't think there was ever one from track 2 to track 1, so you'd have to add one (there are two current crossovers in the opposite direction, from 1 to 2), but doing two crossovers on short, straight sections of track might be easier than reactivating the loop (I don't know). On the other hand, reactivating the outer loop would negate the need to weave between the wall and fence tracks, which would be operationally smoother.

And even if you do that, it doesn't help with capacity on Tremont branches (Huntington/Nubian) at all. The bottleneck then becomes the outer tracks of Boylston-Park, which was already exactly the same as Park-GC (assuming all Central Subway branches use the inner tracks to turn at Park).

I may have gotten confused. You're right with respect to the Tremont branch capacity, I think I was assuming the 30tph figure quoted was split between Tremont and Boylston-Kenmore, which was evidently a misreading. Did I miss where the Kenmore service has gone in this discussion?

 

[Teban54]

I may have gotten confused. You're right with respect to the Tremont branch capacity, I think I was assuming the 30tph figure quoted was split between Tremont and Boylston-Kenmore, which was evidently a misreading. Did I miss where the Kenmore service has gone in this discussion?

I think Riverside is assuming 30 tph on Tremont St subway alone, i.e. Huntington and Nubian (subway), as shown here:

Parsimonious and higher frequencies for all: assuming a 30 tph limit between Park and GC (somewhat arbitrary but fine for now), removing the Washington streetcar from the mix means that you can see higher express frequencies to Nubian and potentially simpler frequencies across the system overall -- two potential distributions being:

15 tph to Park <> Huntington (then splitting among Riverside, Needham, Heath as you wish) and 15 tph on Park <> Nubian, giving you 4-min headways (which is probably the closest we've seen yet to "equal or better")
10 tph on Park <> Nubian, and then 10 tph each of two of the three Huntington branches (Riverside, Needham, Heath, with the third being picked up as a Seaport service)

The implicit assumption is likely that all Kenmore trains terminate at Park.

 

[Charlie_mta]

Fascinating post as usual, and I might go back and add more comments later once I've calmed downs from Bruins-induced irritation. Having experienced quite a few encounters with that atrocious intersection at Summer and the surface route where the South Station offramp comes up from the tunnel, I feel like it would be potentially nightmarish to try and run LRT through there, at least at rush hour. The degree to which that chunk of road gridlocks is nasty. Obviously there are ways to mitigate that to a degree, but I don't know that I love the idea of any project that plans a surface run through there given what I worry it would do to its reliability at peak times.

There's already a bus tunnel running right below the surface there. I would build a portal just to the north (and the south) and run the LRT line through the existing bus tunnel under Dewey Square.

 

[Brattle Loop]

There's already a bus tunnel running right below the surface there. I would build a portal just to the north (and the south) and run the LRT line through the existing bus tunnel under Dewey Square.

Which bus tunnel? The Silver Line?

 

[Riverside]

Great thoughts from everyone, appreciated as always. Let me try to tackle the various points raised...

1. Nubian subway: Which street to go under? Washington, Harrison, or Albany?

This question has downstream implications affecting demand for a surface LRT/BRT route on Washington, even though Nubian subway and Washington service have different roles (the former primarily serving Nubian and possibly BUMC riders, the latter serving South End riders).

• A Nubian subway via Washington or Harrison will likely reduce the demand for local Washington service down to that of a regular bus route, due to significant walkshed overlaps.
• If Nubian subway is routed via Albany instead, Washington service may still merit LRT, as an Albany subway has no hope of serving South End.
• Albany subway's main advantage is lower cost, but how much lower is a question.

I agree that this is the #1 question. That said, I think it's possibly moot: I need to look at the SL numbers (and the Ruggles numbers, for that matter), but we know the number of boardings at Nubian is Very High™, and we know at least some fraction of that Nubian boardings ride all the way to downtown. I think it's possible that regardless of the subway alignment, diverting Nubian <> Downtown riders away from the surface route will drop demand on the surface route sufficiently to make BRT a viable solution (though obviously there are still benefits for LRT in that scenario). But, need to look at the numbers.

The other thing to point out is that if an Albany subway actually runs on the I-93 alignment, it may be possible to construct a dedicated ROW at surface-level with only a handful of grade crossings; as far as I can tell, it's all parking lots under the highway on the northern half, and the southern half has a number of small roads between the highway and the hospital/research buildings which could potentially be reclaimed for a dedicated ROW that runs all the way to Mass Ave & Melnea Cass. (At which point, yes, we probably need to build a short subway in order to achieve the reliability we want. Still, .75 miles (Mass <> Nubian) + .3 miles (Herald plus a portal under 93) = 1.05 miles, which is better than ~1.6 miles (via Washington).

3. If LRT: Tremont St subway, or some surface route?

As Riverside discussed above. This question is obviously irrelevant for BRT.

Neither here nor there but as @Charlie_mta pointed out, strictly speaking we could talk about BRT tunnels through downtown as well. And I mean, maybe we pull a Seattle, and build a bus tunnel under Congress St for these "Navy Line services" (SL4/5, T7, T111, etc), with an eye to eventually converting those BRT routes to light rail at a later date.

Does it make a difference if the service doesn't reach GC? I don't love the idea of any specific route not hitting all the transfers (though the B did it for most of the past decade), but assuming sufficient overall throughput of cars between Park and GC, is there room for more frequencies Park-south if they're turning at Park and not hitting that bottleneck tunnel? Curious if that affects the calculations at all.

I may have gotten confused. You're right with respect to the Tremont branch capacity, I think I was assuming the 30tph figure quoted was split between Tremont and Boylston-Kenmore, which was evidently a misreading. Did I miss where the Kenmore service has gone in this discussion?

I think Riverside is assuming 30 tph on Tremont St subway alone, i.e. Huntington and Nubian (subway), as shown here:
The implicit assumption is likely that all Kenmore trains terminate at Park.

Yes, sorry for the lack of clarity here -- I am indeed assuming that all Kenmore trains terminate at Park on the Inner Loop, which of course creates its own set of issues, but I figure that through-running to GC is a best case scenario, so want to compare against that.

There's already a bus tunnel running right below the surface there. I would build a portal just to the north (and the south) and run the LRT line through the existing bus tunnel under Dewey Square.

You know, I was opening my mouth (proverbially) to object when I paused to think, and then reconsidered. A few points:

• The Transitway tunnel is deep enough down that I don't think it would be feasible to do a quick "dip" in order to cross Summer St
• Immediately below street level is the station lobby... mayyyyyybe you could completely rebuild the Atlantic & Summer intersection to include a transit-only underpass that uses that space but that seems unlikely
• But, your point made me look back again at the alignments between Tufts Medical Center and South Station
• I previously rejected the idea of sending a Washington streetcar into the Seaport subway because I was looking at an insertion point just east of Hudson & Harrison, which precludes a transfer to Orange
• But. If you instead run at street level up Washington St, with a transfer at Tufts Medical Center, and then turn east onto Kneeland, and utilize Kneeland's extra width to add a portal between Washington St and Harrison Ave, you could run a short subway under Kneeland to join a Back Bay-South Station subway around Kneeland & Albany
• The junction might be unpleasant and may need to be a flat junction; the math of the network means that Back Bay <> South Station LRT will be as frequent as Downtown <> Nubian (via subway) LRT, which will be between 10 and 15 tph in all likelihood (4 to 6 min); let's assume that Washington surface LRT will be no more than 10 tph; 10 tph merging to 10 tph is what the C and D lines did pre-pandemic, so maybe it would be doable?
• With your Orange Line connection assured, Washington streetcars could then continue to the Seaport
• You could also look to see if there's anywhere on Atlantic Ave north of South Station where you could add another portal, and have Washington streetcars split off from the Transitway and surface there to continue north. A quick eyeball doesn't suggest any great options for this, though

In a world where we are so lucky as to have both a subway to Nubian and leftover LRT tracks at surface level on Washington, I think I'd be okay sending Washington streetcars to the Seaport as long as there was a reasonable transfer available to the Orange Line.

If a portal on Kneeland really could be an option, then I think that would provide the needed flexibility to ensure that, even if Washington surface LRT is built first, it could still eventually be supplemented by a subway to Nubian -- trading a OSR to Park St/GC for one to South Station and the Seaport, which I think could be sellable.

EDIT: (because why wouldn't I have more to say?) Overall though, my preference at this point is to build an LRT subway/dedicated ROW via the 93 alignment to provide frequent and fast express service to Nubian, and integrate a revived T49 into a "Navy Line" network incorporating the T7, the T111, possibly service to Logan, and possibly service to Everett. I know BRT on Washington St has a weighty, baggaged history, but I feel pretty strongly at this point the surface LRT doesn't meet the criterion of "equal or better" replacement for the El anyway.

 

[Charlie_mta]

Which bus tunnel? The Silver Line?

Yes. I know getting the portals in would be tricky. I'd still run the busses in the Silverline tunnel, but also run the LRT in the same tunnel, similar to what the Harvard Square tunnel did back in the 1950s, and the Seattle bus tunnel did until recently.

 

[Brattle Loop]

Yes. I know getting the portals in would be tricky. I'd still run the busses in the Silverline tunnel, but also run the LRT in the same tunnel, similar to what the Harvard Square tunnel did back in the 1950s, and the Seattle bus tunnel did until recently.

It's the "getting to the Transitway" that's the problem, for me. Somewhere in one of these threads (either this one or Crazy Transit Pitches) there was a pretty thorough back-and-forth from a few years ago on how it might not even be possible to get into the transitway via Atlantic, and the only other option is via Essex, which has its own difficulties.

 

[Riverside]

It's the "getting to the Transitway" that's the problem, for me. Somewhere in one of these threads (either this one or Crazy Transit Pitches) there was a pretty thorough back-and-forth from a few years ago on how it might not even be possible to get into the transitway via Atlantic, and the only other option is via Essex, which has its own difficulties.

Two F-Line posts on the topic:

Green Line Reconfiguration

Northland = Upper Falls, as the historic depot is at the Oak St. grade crossing and Northland is on the corner of Oak/Needham 1200 ft. away. That's the closest physical stop location. As mentioned, the Avalon site (placemarked "Needham St. Station") was the weakest link in the proposed stop...

archboston.com

Green Line Reconfiguration

Couldn't a green Line tunnel along Essex Street be deep enough to avoid undue impacts on Boylston Station and the Orange Line tunnel? If you started the tunnel to come off the existing Green Line tunnel between Charles Street and Arlington Street, begin dropping immediately and pass under both...

archboston.com

 

[Teban54]

Two questions:

1. LRT and BRT mixed-running in the Transitway: SL buses have speed restrictions there due to tunnel dimensions (see Wikipedia quote below), so would this make mixed-running a problem in reliability?
2. Unrelated to the ongoing discussion, but something I thought of while reading the F-Line post above. Looks like underpinning the old GL/OL stations and tunnels were a significant part of SL Phase III's failure, but would underpinning existing stations always blow up the cost? Or was it only due to the century-old stations, but may have more manageable costs elsewhere? (The specific station I was thinking of is Kenmore, for another proposal that I'm considering.)

The tunnel was built for a maximum speed of 25 miles per hour (40 km/h); the narrow lanes without guided buses limit actual speeds to 15 miles per hour (24 km/h).

 

[JeffDowntown]

Two questions:

1. LRT and BRT mixed-running in the Transitway: SL buses have speed restrictions there due to tunnel dimensions (see Wikipedia quote below), so would this make mixed-running a problem in reliability?
2. Unrelated to the ongoing discussion, but something I thought of while reading the F-Line post above. Looks like underpinning the old GL/OL stations and tunnels were a significant part of SL Phase III's failure, but would underpinning existing stations always blow up the cost? Or was it only due to the century-old stations, but may have more manageable costs elsewhere? (The specific station I was thinking of is Kenmore, for another proposal that I'm considering.)

Buses in the transitway should be upgraded to guided operation.

 

[737900er]

LRT and BRT mixed-running in the Transitway: SL buses have speed restrictions there due to tunnel dimensions (see Wikipedia quote below), so would this make mixed-running a problem in reliability?

It's also that any buses through the Transitway would be coming from the Ted after running in mixed traffic, which will always be a high variability and indirect operation. Once there is LRT in the transitway, there's no reason to have SL1 in its current headway-boosting capacity; Red-Blue and grade separated transit at Logan will decrease loads to Logan on SL1 too. The LRT would presumably consume the SL2. That leaves SL3, which is probably served with bus lanes (possibly shared with T7, T12, or the vestigial SL1) on the surface. @Riverside did a great analysis of how most SL3 riders through the tunnel are going to South Station; going through the transitway just adds time, and most surface routings would still allow an intermediate surface stop in the Seaport.
It's also clear that the T wants to make Express Buses a thing of the past. While BEBs would enable services like Lynn-South Station via Ted and Transitway, which could actually be run today with geofencing, I don't see much appetite for those kind of services.

 

[Riverside]

It's also that any buses through the Transitway would be coming from the Ted after running in mixed traffic

Well, technically we could be talking about a Washington St BRT that runs into the Transitway and terminates in the Seaport, but that's really just trading one set of reliability problems (TWT) for another (Washington).

But yes, once we have LRT in the Transitway, I think the scales are tipped in favor of relocating the BRT elsewhere. (And worth remembering that another option for a South Station - Logan service is one that terminates in the bus terminal which will eventually be located significantly closer to both the subway tracks and the mainline tracks. Run every 10 minutes, maybe brand it as part of Logan Express, etc etc.)

 

[Tallguy]

Buses in the transitway should be upgraded to guided operation.

A very inexpensive upgrade

 

[sneijder]

I forget where this has been discussed, but how much of a non-starter is it to quad-track the central subway (from kenmore to govt center?) The outside pair of tracks already exist from Boylston to Park St & at kenmore, and it would provide some capacity relief to the central core where all lines run through. Of course modernizing signals to moving blocks would probably also boost capacity significantly so trains can run closer together.. and this quad-track probably would be combined with some Pleasant St extension which won't be on the docket until at least 2060..

We'd need to get rid of Park St short turns (and bulldoze the loop), re-do the GL triangle platform at GC, fix the Boylston Curve, and build a duck-under junction for the westbound E-train towards Heath st. And it seems like Copley, Arlington, and Hynes would all be expensive as the tracks aren't deep enough under ground to build a mezanine.

 

[Tallguy]

I forget where this has been discussed, but how much of a non-starter is it to quad-track the central subway (from kenmore to govt center?) The outside pair of tracks already exist from Boylston to Park St & at kenmore, and it would provide some capacity relief to the central core where all lines run through. Of course modernizing signals to moving blocks would probably also boost capacity significantly so trains can run closer together.. and this quad-track probably would be combined with some Pleasant St extension which won't be on the docket until at least 2060..

We'd need to get rid of Park St short turns (and bulldoze the loop), re-do the GL triangle platform at GC, fix the Boylston Curve, and build a duck-under junction for the westbound E-train towards Heath st. And it seems like Copley, Arlington, and Hynes would all be expensive as the tracks aren't deep enough under ground to build a mezanine.

You won't need a mezzanine with the right fare collection software