Green Line Reconfiguration

KCasiglio said:
Thanks! Just to clarify, these were in-service cars right? Not just moving equipment when they theoretically could have accounted for making sure the cars weren't passing each other at the same time?
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Yes...full revenue service for 7 years between 6/10/1901 and 11/28/1908 while the Orange tunnel was being constructed. During that period trolleys from Public Gardens portal took the current/inner tracks at Boylston and looped at Park while trolleys from Haymarket portal took the inner tracks of the 4-track tunnels and looped at Brattle Loop; there was no thru trolley service between Park and Scollay. El cars ran thru Haymarket-Boylston on the outer tracks on temporarily-installed third rail, and temporary wood high platforms were installed on the outer tracks for boarding. El service was fileted between the subway and Atlantic Ave. El for traversing downtown (whereas 1899-1901 it was only the Atlantic Ave. El). Tremont St. reverted back to full trolley thru running as soon as the Washington St. tunnel opened for business.
 
F-Line to Dudley said:
The Tremont tunnel carried Orange Line El cars thru from Haymarket portal to Pleasant St. portal from 1901-1908, and those are quite a bit wider than even current LRV's let alone the PCC's. The last 2 batches of OL cars ran 111" wide, and it's unlikely that the first batch of El cars 120 years ago were narrower than that by any more than a couple of inches given that they boarded at downtown platforms in the Orange tunnel that still exist today. So it's not physically possible that any part of the 1897 Tremont tunnel is too narrow for Type 7's/8's/9's/10's.
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Except that the GL tunnel curve from Tremont St to Boylston St might be tight, because the elevated trains didn't go in that part of the tunnel.
 
hey guys, back again

i was wondering if 4 tracking park street-government center is possible by building the second pair of tracks below the existing ones?
im not sure if there would be room at park street without rebuilding that portion of the red line, but theres room for an incline abefore government center where tremont street turns into cambridge street

ik this is a bit of a crazy one but i think that 4 track to gov. center and beyond is central to the future of the green line
 
Hooledeli said:
hey guys, back again

i was wondering if 4 tracking park street-government center is possible by building the second pair of tracks below the existing ones?
im not sure if there would be room at park street without rebuilding that portion of the red line, but theres room for an incline abefore government center where tremont street turns into cambridge street

ik this is a bit of a crazy one but i think that 4 track to gov. center and beyond is central to the future of the green line
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Maybe? The main constraint would be that at GC you need to get under the Blue Line, and since the distance between Park and GC is quite short it might not be possible to do that with a reasonable grade, although I can't find a proper diagram of the depths of everything at GC so it's a little hard to answer this definitively.

The second question is what is the goal? Quad-track is nice and all, but what exactly is this meant to accomplish? The B/C branches (And a hypothetical restored A branch) only really need to go to Park St IMO. If we're really worried about the BL transfer there are better alternatives like a connecting pedestrian tunnel between Park and GC or even BL to Kenmore. If it's expanded service to the GLX branches, the main capacity constraint is that it's a branched service that converges on double track to go through Cambridge and across the Lechmere viaduct. Taking terminating GC trains out of the way might improve things a bit, but I'm not sure it would justify the cost which could end up comparable to BL to Kenmore, assuming we're willing to sacrifice Storrow.
 
TheRatmeister said:
Maybe? The main constraint would be that at GC you need to get under the Blue Line, and since the distance between Park and GC is quite short it might not be possible to do that with a reasonable grade, although I can't find a proper diagram of the depths of everything at GC so it's a little hard to answer this definitively.

The second question is what is the goal? Quad-track is nice and all, but what exactly is this meant to accomplish? The B/C branches (And a hypothetical restored A branch) only really need to go to Park St IMO. If we're really worried about the BL transfer there are better alternatives like a connecting pedestrian tunnel between Park and GC or even BL to Kenmore. If it's expanded service to the GLX branches, the main capacity constraint is that it's a branched service that converges on double track to go through Cambridge and across the Lechmere viaduct. Taking terminating GC trains out of the way might improve things a bit, but I'm not sure it would justify the cost which could end up comparable to BL to Kenmore, assuming we're willing to sacrifice Storrow.
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It also wouldn't add that much additional throughput for its cost over simply reconfiguring the layout of GC station on that station's existing footprint. The 'wedge' there is wide enough and structurally-unencumbered enough on top that you could theoretically do crossovers to/from the Brattle Loop track in each direction and separate the station into twin-island thru platforms (1 OB island, 1 IB island) that better segregates looping trains from thru trains. Then use the combination of Park St. crossovers with GC crossovers to prioritize the platform occupancy of the furthest-running trains such that an orderly procession on the 2-track segment between Park-GC doesn't add to any delay time. Essentially: optimizing the shit out of dispatching at the two relief-valve loop stations with organization-before-electronics-before-concrete to increase overall capacity. Considerably less cost than a tunnel widening megaproject, for 65% of the traffic management utility. We definitely don't have to blow too much shit up to wring adequate additional capacity and efficiency out of the Central Subway system in a Reconfig universe.
 
i want to do it for future proofing mostly, 4 tracking to north station then having 2 tracks go north to sullivan square and chelsea and beyond, in general just expansion of rapid transit without having to build a new tunnel through downtown (except parkstreet-gov center)
 
Hooledeli said:
i want to do it for future proofing mostly, 4 tracking to north station then having 2 tracks go north to sullivan square and chelsea and beyond, in general just expansion of rapid transit without having to build a new tunnel through downtown (except parkstreet-gov center)
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"Future proofing" is not something you spend a heinous amount of money to ensure. It's at most a side benefit you achieve through other means, not the raison d'être. And make no mistake, re-digging the 1897 tunnel under narrow streets, historical properties, and multiple levels of tunneling to shiv in +2 tracks is going to be heinous on the expenses. You need to provide a specific usage case where 4 tracks Boylston-NS is going to be absolutely necessary for the basic functioning of the system. When branches can/do turn at Park and GC, and when the whole point of the various appendages of GL Reconfig is to load-spread the transfers all around the system away from the Downtown nerve center...it's not self-evident what's absolutely necessary about 4 tracks.
 
TheRatmeister said:
Maybe? The main constraint would be that at GC you need to get under the Blue Line, and since the distance between Park and GC is quite short it might not be possible to do that with a reasonable grade, although I can't find a proper diagram of the depths of everything at GC so it's a little hard to answer this definitively.
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I was made aware of these track charts. Total height change would be about 40 ft over 1100 ft, or a 3.6% grade. So there's no reason it's technically impossible or infeasible, just not particularly useful/cost effective given the GLRC scenario.
 
There has been a lot of noise about the bad performance on the GLX, particularly to Medford/Tufts. How hard would it be to just +1 from Boylston to a Bay Village loop/stub and convert the Medford branch to its own own thing, separate from Huntington Ave to maintain connection to Red? This would presumably also allow remove the Brattle Loop as a system-limiting curve.
 
737900er said:
There has been a lot of noise about the bad performance on the GLX, particularly to Medford/Tufts. How hard would it be to just +1 from Boylston to a Bay Village loop/stub and convert the Medford branch to its own own thing, separate from Huntington Ave to maintain connection to Red? This would presumably also allow remove the Brattle Loop as a system-limiting curve.
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Or, as an even cheaper intermediate option, is it possible to install a switch south of Boylston Outer (either in the tunnel or near the former Pleasant St portal), and turn trains around from there without a Bay Village station and a platform?
 
Teban54 said:
Or, as an even cheaper intermediate option, is it possible to install a switch south of Boylston Outer (either in the tunnel or near the former Pleasant St portal), and turn trains around from there without a Bay Village station and a platform?
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I thought about that. Presumably either way you have to open the portal back up and rehab the tunnel, which is where the cost would be. Cheaper to build the X at-grade and an at-grade stub-end or loop station could probably be built without any vertical circulation for cheap too.

I also suspect that grades and length may be a challenge to install an X or two crossovers on the very brief section where both directions share the same tunnel, although I've never been down there myself.

Cut the B back to Park Street, cut the D back to North Station, and swap the E to Union Square.
 
I understand that BLX to Kenmore is on the GLR map because it'd provide a Lime->Blue connection that'd otherwise be lost with Lime's terminus being cut back from Govy to Park.

Imagine a world where there's funding & willpower for GLR, but not for the BLX to Kenmore. Was there any analysis of an alternate BL connection, for example a ped tunnel between Park and Govy, or between DTX and State?
 
kdmc said:
I understand that BLX to Kenmore is on the GLR map because it'd provide a Lime->Blue connection that'd otherwise be lost with Lime's terminus being cut back from Govy to Park.

Imagine a world where there's funding & willpower for GLR, but not for the BLX to Kenmore. Was there any analysis of an alternate BL connection, for example a ped tunnel between Park and Govy, or between DTX and State?
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DTX and State are really close to each other. OL Forest Hills at State and Oak Grove at DTX platforms are only about 20-30 feet apart at the ends of the platforms -- but I gather there is a transformer or other electrical switchgear in the intervening space that needs to be moved.
 
No, it's about 300 feet between the existing platform tips. And, as we've discussed before, that's at the very tips of both stations. The actual walking distance between Red and Blue would be about 1500 feet - triple that of the Winter Street Concourse - with multiple stairs/elevators required. That's equivalent to transferring between Back Bay and Copley, or the Red Line to the far end of a CR train at South Station. It's simply not a transfer that would be well-used.

If Blue is still extended to Charles/MGH to get the Red transfer, then the lack of Lime transfer wouldn't be a big deal. There would be cross-platform transfers between the inner and outer tracks at Park and Boylston. Yes it would be an extra transfer, but the travel time penalty would be pretty low given the high frequencies available.
 
The EGE said:
No, it's about 300 feet between the existing platform tips. And, as we've discussed before, that's at the very tips of both stations. The actual walking distance between Red and Blue would be about 1500 feet - triple that of the Winter Street Concourse - with multiple stairs/elevators required. That's equivalent to transferring between Back Bay and Copley, or the Red Line to the far end of a CR train at South Station. It's simply not a transfer that would be well-used.

If Blue is still extended to Charles/MGH to get the Red transfer, then the lack of Lime transfer wouldn't be a big deal. There would be cross-platform transfers between the inner and outer tracks at Park and Boylston. Yes it would be an extra transfer, but the travel time penalty would be pretty low given the high frequencies available.
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The connection Red Blue would not be great, but the tips of the platforms cannot be 300 ft. apart. The surface walk from Franklin head house to Old South head house is 200 ft. And the State platform extend further down Washington at least 100 more feet, likely much more.
 
kdmc said:
I understand that BLX to Kenmore is on the GLR map because it'd provide a Lime->Blue connection that'd otherwise be lost with Lime's terminus being cut back from Govy to Park.

Imagine a world where there's funding & willpower for GLR, but not for the BLX to Kenmore. Was there any analysis of an alternate BL connection, for example a ped tunnel between Park and Govy, or between DTX and State?
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I've suggested a Park-Gov Center tunnel before, it's hard to tell but I think the existing tunnel might actually be wide enough if fencing was put up to separate trains from people.
 
JeffDowntown said:
The connection Red Blue would not be great, but the tips of the platforms cannot be 300 ft. apart. The surface walk from Franklin head house to Old South head house is 200 ft. And the State platform extend further down Washington at least 100 more feet, likely much more.
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Ari Osfevit's blogpost below also references the 300 ft number. It seems to be between northbound OL DTX and southbound OL State platforms, the latter of which extends a little bit beyond the Old South Meeting House entrance.

amateurplanner.blogspot.com

The mystery of the 600 feet between the Red and Blue lines

Last month, the MBTA presented its " Focus40 " list of items it wants to complete by 2040. The Commonwealth Magazine article noted that the ...
amateurplanner.blogspot.com amateurplanner.blogspot.com

This blogpost is an excellent read in itself and highlights why a Red-Blue pedestrian tunnel is problematic. In addition to the long walks, the biggest problem is:
  • The 300 feet which would be needed for an additional tunnel would have to go through and underneath the building foundations outside of the footprint of the street, because the Orange Line is already threaded under Washington Street, which is very narrow.
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I have to think the same problem will occur at Park-Gov't Center for a Lime-Blue transfer, as Tremont St is even narrower than Washington St. And as Ari said, such benefits can be realized by either having the passengers take another Green Line train for 1 stop (which most people will probably do), or allowing an out-of-system transfer.
 
JeffDowntown said:
The connection Red Blue would not be great, but the tips of the platforms cannot be 300 ft. apart. The surface walk from Franklin head house to Old South head house is 200 ft. And the State platform extend further down Washington at least 100 more feet, likely much more.
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1724709184747.png
 
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