Crazy Transit Pitches

Understand though, that is NOT at all what SL Phase III was proposing to do. SL III was very much a South Station-first, transfer-oriented, Seaport-by-proxy service. The archival documentation scattered in nooks and crannies of Wayback Machine spells that out pretty clearly what the primary demand question was.

What you're proposing is an entirely new and different transit service that has to compete head-to-head for priority pecking order with the top-demand projects, of which SL III or equivalent is still one of far greater need. The demand-inferior half-duplication through the back end of the Seaport and lack of any Red Line relief is going to be a serious demerit for giving it any oxygen on the pecking order, since it doesn't answer the top demand priorities. It will probably not get an at-bat at all until it's time to consider SE-quadrant Urban Ring options. Then...sure, run the Ring through the HOV lanes and you can have your cake too by spurring some trolley tracks down Herald St. from the Washington St. incline and alt-routing to your heart's content.

But it's not an SL Phase III substitute. It's not a down-payment on an SL Phase III substitute. It's not in the same universe as SL Phase III, because it doesn't answer any of the same top-priority demand questions SL Phase III did. South Station is the locus of Seaport transit, not BCEC or Silver Line Way. The need for direct access across downtown was all about South Station being the locus, but a second pipe being needed through South Station to keep Red congestion from paralyzing everything. If that locus has somehow shifted east deeper into the neighborhood in the 8 years since SL III was mothballed, then it's a whole new ballgame needing whole new from-scratch demand studies and ridership math to justify its existence. Because that's an entirely different value proposition from what SL III was posing.

Somehow I doubt those numbers have shifted in 8 short years to put the locus anywhere but where they always pegged it.
 
I'll grant you that what I've proposed here is a different service pattern to SL3. Yes, certainly. Should it be studied? I believe so, given that the Seaport is now a major commuting destination with far too few transit options. Plus, because the potential HOV routing makes use of three pre-existing tunnels, 90% of the route is already essentially built. Do I think it's feasible off the bat? No. Should it be studied? Yes. I'd still also arge that it does relieve the RL as long as we're talking about Seaport-bound traffic, rather than South Station-bound traffic. But let's leave it there at this point.
 
FWIW, here's a quick-and-dirty Final System Map sampler (your build priority may vary) for the whole area showing:

  • Tufts Station, Tremont Tunnel extension, and South End trajectory Alternative for SL III replacement to South Station w/ Ink Block infill
  • the Washington St.-replacement trolley portal
  • the E-replacement Back Bay routing
  • SL1 (as-is)
  • the UR LRT re-use of the HOV lanes out of Broadway
  • Rest of the UR LRT route involving trolley reservation on Melnea Cass + Mass Ave. Connector, Haul Rd. mixed-running, slip ramps on/off the Haul Rd., and the Broadway trolley tunnel.
  • the Chestnut Hill-style non-revenue track connection along Herald St. linking the Washington trolley to the UR trolley, for immediate use on equipment swaps and future-considerations revenue service alt. routings
Note in particular:

  • recycling of the Broadway Upper trolley tunnel for the UR
  • insertion point into the HOV lanes via air rights viaduct subdividing the Cabot Yard air rights building parcels on Traveler and Foundry St.'s decked over the Red Line tracks.
  • Air rights real estate on the Pike is leveraged to underwrite some cost of the SL III/Washington trolley construction along Marginal, them the later E-replacement construction along Marginal. Air rights real estate over Cabot on both the Traveler and W. 4th blocks underwrites UR costs.
  • As described in the prior post, 2 trolley tracks fit in the EB HOV tunnel, so you still have 2 lanes of WB tunnel to play with for rubber-tire vehicles.
  • NO Pike-bisecting tunneling allowed anywhere east of the Washington St. overpass, because that's where the NSRL portal goes. Washington trolley has to split off before Ink Block station.
  • Assume all of these builds are staggered-out separately, especially the BBY connector and UR from the more critical SL III replacement. UR and alternate backdoor routings, as described, come well after the full SL III replacement on demand priority and time much better for the UR where the radial route is ideal match for the backdoor. Tufts Station short-turns and the Washington trolley can even go first if we're segmenting the long-duration SL III replacement build into a bite-size fast-start segment that can open early.
  • All priority pecking order is debatable, as are exact routings. Just exercise common sense on pecking order, as some of these clearly dwarf others on demand vs. time.


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Nice - I like the tie-in to the UR via the Broadway trolley tunnel - clever.
 
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Here's a slightly modified Marginal Street alignment to South Station. It is based on a scheme DaveM posted a while back. The difference here is that this scheme connects to the Transit Way tunnel at the Essex Street bellmouth after running under South Street, instead of extending the transit way tunnel turn around with a portal on Atlantic Ave.

This scheme avoids crossing under and beside the Dewey Square I 93 tunnel and reduces the length of tunnel. A public private partnership could also be worked to create a new station on Kneelland Street at the Veolia steam station redevelopment parcel.

Below is a street view showing how close the existing Tufts station head house is to the Eliot Norton Park (location of the proposed Green Line Tufts platforms).

jfV3yCS.jpg
 
I remember reading about DaveM's proposal a while back. I don't remember if anybody ever clarified if that tight 120° turn is possible. Is it?
 
stefalarchitect said:
I remember reading about DaveM's proposal a while back. I don't remember if anybody ever clarified if that tight 120° turn is possible. Is it?
Click to expand...

I made the turn radius larger than Boylston , I can't remember off the top of my head exactly what it was.
 
Upstruk said:
Here's a slightly modified Marginal Street alignment to South Station. It is based on a scheme DaveM posted a while back. The difference here is that this scheme connects to the Transit Way tunnel at the Essex Street bellmouth after running under South Street, instead of extending the transit way tunnel turn around with a portal on Atlantic Ave.
Click to expand...

South St. is highly-variable width pinched to as low as 40 ft. building-to-building width and 30 ft. sidewalk-to-sidewalk in a couple spots. It is uniformly much more constrained than Essex to dig under, and one of the hardest single streets you could choose to tunnel under anywhere between Boylston and SS. The great lesson from the SL Phase III experience is that cost bloat is exponential when trying to mitigate clusters of structural impactors, so the high concentrations of them run up that score faster than cost trims elsewhere lower it. This routing does not improve your feasibility odds at all because it's based on spurious logic that savings in some above-ground running 1:1 offsets the hard tunneling costs. It doesn't. South St. being one of the very narrowest of choices un-does the cost savings of the surface jaunt, the need to change grades for 2 portals dings it a little bit more inefficiently, and the extremely sharp right-turn onto Essex a block away from the sharpish turn into the Transitway imposes a painful Boylston curve-esque flow kink in transit ops. I very much doubt the total price tag is going to be enough of an improvement to justify all the engineering demerits in the scoring.

Sorry if I'm sounding like a broken record...but this is one more set of renders that just isn't learning any lessons about the value of aggregate feasibility scoring. We're still not operating in the real world of project evaluation here. The real world of engineering scoring killed SL Phase III on exactly these sorts of sins. The replacement proposal either addresses ALL of the flaws and nets a path of least resistance that checks out on aggregately best scoring, or it's going to fail for the same reason SL III did. Fail even if it's somewhat more benign, because it directly chooses to make the same mistakes of seeking out the arbitrarily difficult for proof-of-concept stubbornness. Half-and-halves don't cut it. Trying to live between the lines with cuts in one place so one can double-down on the lowest-percentage play elsewhere doesn't cut it. At the end of the day it fails on scoring for the same exact reason. And at the end of the day this project still isn't a theoretical Crazy Transit Pitch, it's an unfunded mandate from 10 years ago.

This scheme avoids crossing under and beside the Dewey Square I 93 tunnel and reduces the length of tunnel. A public private partnership could also be worked to create a new station on Kneelland Street at the Veolia steam station redevelopment parcel.
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Crossing under Dewey was never an issue; that's spurious logic. The straight trajectory under Essex and the Dewey tunnel to Chinatown Park was the most straightforward piece of tunneling for SL Phase III with the most reliably fixed costs because the entire shot was pre-prepped for digging in the CA/T and Transitway construction. The route all points west to Boylston was where SL III lost the plot and needs troubleshooting. There was never a need to troubleshoot here, so you're inventing justification that doesn't exist to further pursuit of that low-odds South St. proof-of-concept.
 
I measured South Street from the Cad files on the BRA website. http://www.bostonredevelopmentauthority.org/planning/urban-design/urban-design-technology-group/downloads-and-submissions It is at its narrowest 59 ft building to building. Hudson Street is 49ft building to building. I do agree that the two 90 degree turns in a row are not ideal.

I looked at this option not to be stubborn, but in recognizing that Hudson Street is not the easiest street to tunnel under. South Street is wider and much of this route is above ground, with the possibility of a public private partnership.

As another alternate has anyone seen examples of subway tunnels under existing highway rights of way? Could the route go down Essex street and then follow below the Dewey Sq tunnel all the way to Marginal. Would this be more cost effective than tunneling between/below the tunnel and the Radian tower (requiring tunnel wall undermining mitigation) and then under Hudson Street or tunneling under South Street?
 
Alright transit people, tell me why it can't be done:

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OL wye to Seaport via HOV lane.
 
Where does it go? Just to BCEC? Stop at A street? Where is the end of the line?
 
I'd imagine branching the Orange Line between Downtown and Back Bay would be a serious problem.
 
For one, you're taking away capacity from the existing line. Those coming from the north lose frequency to Back Bay and Ruggles (and thus the LMA); those coming from the south lose frequency to all of downtown. There's a reason you don't see three-sided lines on existing transit systems: they aren't as useful as you'd think.

For two, you're constructing three massive grade-separated junctions under existing buildings, city streets, highway, and rail line. Way larger radii than the Green Line, and vastly more disruptive.

For three, trying to run anything under the entirety of the South Bay Interchange is probably a nonstarter. Too many different things to underpin, especially when you're trying to get the tunnel to the HOV lanes as well.
 


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Here is a modified version of Shepard's HOV tunnel conversion scheme. As discussed in the past the Green Line is extended along the existing Tremont Street tunnel to a new underground station which connects to the Orange Line at Tufts Medical. From here the tunnel is extended under the pike and Herald Street where it emerges to the surface under the I-93 viaducts and enters into the existing HOV tunnel entrance. Stations could possibly be built on Herald street for the Ink Block and along A street to serve future development.

I believe the HOV lane does not have an exit to the Seaport (please correct me if I am wrong) so a new portal to the surface would be required. Here the line would run along the Haul Road where a new station would be built between the BCEC and WTC Silver Line station. This is where the new garage "Transportation Center" is proposed. This station would provide transfers to the existing Silver Line Station.

This new station is 1/2 mile from Fort Point Channel so this station provides Green Line service a 10 minute walk from most of the Seaport. The line could then be extended along a newly constructed E street to serve future development along the "Pappas Properties" and some of the traditional South Boston neighborhood.

Red Line, Chelsea, Airport and East Boston (Blue line) riders take the Silver Line to the Seaport. Green and Orange line rides take this new route. Seaport and South Boston use this line to Theater District, North Station etc.

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Upstruk said:
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When I saw this image, I thought your pitch was going to be, "Just f*cking walk, people!"

...indeed, HOV lane exits only to the boat section immediately before the TWT entrance
 
Upstruk said:


aPTG4H4.jpg
[/IMG]

Here is a modified version of Shepard's HOV tunnel conversion scheme. As discussed in the past the Green Line is extended along the existing Tremont Street tunnel to a new underground station which connects to the Orange Line at Tufts Medical. From here the tunnel is extended under the pike and Herald Street where it emerges to the surface under the I-93 viaducts and enters into the existing HOV tunnel entrance. Stations could possibly be built on Herald street for the Ink Block and along A street to serve future development.

I believe the HOV lane does not have an exit to the Seaport (please correct me if I am wrong) so a new portal to the surface would be required. Here the line would run along the Haul Road where a new station would be built between the BCEC and WTC Silver Line station. This is where the new garage "Transportation Center" is proposed. This station would provide transfers to the existing Silver Line Station.

This new station is 1/2 mile from Fort Point Channel so this station provides Green Line service a 10 minute walk from most of the Seaport. The line could then be extended along a newly constructed E street to serve future development along the "Pappas Properties" and some of the traditional South Boston neighborhood.

Red Line, Chelsea, Airport and East Boston (Blue line) riders take the Silver Line to the Seaport. Green and Orange line rides take this new route. Seaport and South Boston use this line to Theater District, North Station etc.
Click to expand...

I think the hov tunnel needs to be retained for vehicular traffic because it is the only way for NB 93 traffic to enter onto EB 90 (Ted Williams tunnel to Logan).
 
Charlie_mta said:
I think the hov tunnel needs to be retained for vehicular traffic because it is the only way for NB 93 traffic to enter onto EB 90 (Ted Williams tunnel to Logan).
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That's not accurate. Exit 20 off 93N will do it.

There is however an HOV/Express-only EB on ramp @kneeland street / south bay that's quite handy, and which would be a meaningful loss for the bus terminal in particular.
 
CSTH said:
That's not accurate. Exit 20 off 93N will do it.

There is however an HOV/Express-only EB on ramp @kneeland street / south bay that's quite handy, and which would be a meaningful loss for the bus terminal in particular.
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That would be a big loss for the bus terminal. I know at least a few of the bus lines (Dartmouth Coach for example) stop at South Station on the way to Logan.
 
They definitely could. There are bus/LRV tunnels in Seattle, and there used to be one in Harvard Square until about 1960.
 
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