F-Line to Dudley
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PART I reply . . . (whoops...hit "post" out-of-sequence from Part II)
Yes...this is a big myth I've explained at length before. BLX's great hope is not the RUR-rapid transit connection. It's the fact that Lynn is a mega bus terminal and the linchpin of last-mile North Shore transit...but the bus service levels are historically effed because of the distended Wonderland + downtown runs down 1A every 4xx series route has to make, which wrecks equipment rotations to the point where all local routes end up frequency-starved. Greater than one-third of all of the 4xx's duty cycles are 'wasted' in the distended running miles. If you culled all @ Lynn Terminal like they used to be pre-1970 (before the T acquired the local bus carrier) the same equipment cycles can be recouped into >1.5x the last-mile frequenies everywhere from Point of Pines to Danvers & Beverly.
Is that not goddamn crucial for RUR growth alone? It's only half-cocked if bus frequencies persist forever at starvation level at Salem, Beverly, Swampscott, and others because of this systemic breakage. North Shore writ-large's transit shares will remain off-scale low compared to any other similar region (like South Shore) so long as the last-mile problem remains acute and unsolvable like that. Eastern Route frequency increases end up swimming against a headwind to bank their growth because the region-wide feeders not only stay capped low-frequency forever...but get worse with time as escalating 1A congestion chews more duty cycles. There's no other tactical nuclear strike project other than BLX that fixes this glitch with any efficiency. You can build a bigger Lynn Garage and stuff more Yellow-paint bodies there all the same; you still lose upwards of 33-40% of any fleet's duty cycles on the duplicating 'waste' miles.
Remember this. It takes more than one mode to tango a transformation. The RUR potential, no matter how great, still has one hand tied behind its back if the feeder buses are incapable of growing their frequencies. And incapable they will be until you build BLX. BLX arguably does more than RUR on the added one-seat utility because the giant expanse of swamp culls travel patterns from Lynn-proper to Revere not Chelsea...but even if you posit that the RR vs. subway modes can be pitted head-to-head at that task it's missing the entire point. BLX is the only multimodal kingmaker that flips all North Shore transit shares...to the very last mile...on its head. Nothing else.
Ultimately the goal here is to get all transit shares on the North Shore right-sized by taming the outsized car culture. That's only accomplishable by the megaproject that heals the bus breakage as part of its core proposition.
Yes. Maybe we need to highlight what a big effing deal the Urban Ring is going to be to clarify this, because it's challengingly abstract to parse out today vs. what we typically think of as Boston transit patterns. With full grade separation everywhere except for Chelsea St. lift bridge it's going to be a fast trip to go from Sullivan to Logan on a luggage-rack equipped Type 10 consist, with alternating 6-min. frequency filets between the Central Subway (Seaport/South End via North Station origin? Brattle Loop/GC origin?) and the Cambridge/Northwest Ring quadrant (Harvard Sq. origin?). Ultra-mega bus hubs like Sullivan & Harvard have never had such fast trips to Logan before. Kendall--such a very heavy airport-using audience--has never had such fast trips to Logan before. Likewise, with a hookup to a bus+trolley grade separated Terminal Transitway you can ensure that these are true one-seats to check-in/pick-up and not the forced transfer to some sort of shuttle that comes from any other trajectory including this NSRL addendum. Much like how the BLX-Lynn argument tends to get lost on the modal warfare singular tangent vs. the far huger multimodal coattails, real transformation comes first from full-court press across the spider map on more-dynamic service patterns first. Hence, the reason why our five-alarm most urgent projects are all radials and load-spread transfers...and not "route miles" for route miles' sake. The dynamism we seek comes from pushing a very different kind of distribution across the city.
When doing project scoring of these pitches you absolutely do have to weigh the monolithic "nice-to-have" against the more immediately implementable and multi-dimensional services along these high-leverage radial routes. It's not a bunch of 2D lines on a map going full steel-cage match against each other; what do the actual service patterns accomplish. We've discussed at length in the GL Reconfig/"Reimagined" thread that it takes some mental steps to perceive just how different and more dynamic the LRT system is going to be when both north hooks of the Urban Ring are built and cooking. These alternating run-thru patterns straight to the Terminals are excellent examples of that more "4D" dynamic and how it tickles the geographic spread. As one example...let's say you're a born pessimist about dispatching from Downtown to the Terminals on sustained 6 + 6 = 3 min. alternating headways . Well, when it's all interconnected there's nothing stopping you from adding a short-turn frequency of single-car trolleys solely between the Terminals and the BL Airport station so the thing is at full-on APM-level headways above and beyond the copious service coming from the west. Mind you, with SL1 still doing its thing on rubber tires shorn of carrying the water for excess intra-Seaport demand and saving buttload of time in its own right on the multimodal Terminal Transitway.
Tally up the full dynamic range of radial patterns you can unleash here, and then quantify how much is still left lacking from a cross-Harbor RR bore? It's still unfathomable that we arrive at anything "Paris-level" in overall airport centricity mandating that at anytime before second half of the century.
Very difficult, to be sure. Because the tunnel spaghetti makes all existing NSRL trajectories very precise slotting, while netting offset deep-cavern stations that no one would exactly call minimal-effort transfers for getting up/across to the Dewey Sq. concourse. It very much is what it is. Ditto with the Silver Line being a kinda rough shoehorn fit where its concourse sits amid all the infrastructure stacking. We haven't gone into engineering depth enough to place this would-be split spatially vs. the station platforms. But chances are overwhelming that even if it's possible it'll either take split before station onto dedicated SS Under platforms to the side at more station cost and less-efficient per-platform traffic utilization...or a crossover minefield just past the platforms imposing a capacity penalty. This is important as the Eastie bypass seems to be propping up the 2-track Congress St. alignment in quasi-aversion to the CA/T alignment. Any additional negative traffic impacts to only 2 tracks thru Downtown is going to hurt. And going to make the broad-based statewide sell job way harder because some regions will have to be prioritized over others and some regions may start being shut out from run-thru patterns. That critical-mass voting coalition is a lot harder to hold together @ 2 tracks vs. 4, so beware how much the bypass actually changes the project's fortunes from the core 2-track Congress vs. 4-track CA/T debate.
The infrastructure placement is pinned into born compromise by its surroundings. Actual results may not be as fluid as necessary to sidestep the whole straight-ahead mainline track capacity conundrum.
Second: you argue that this East-West link would reduce the need for BLX to Lynn, but I'm skeptical. One of the arguments in favor of a North-South link is that it would allow northside riders better access to downtown, which North Station is more removed from than South Station. But South Station itself still isn't the be-all-end-all. Many riders have destinations outside of the Financial District (which is better served by the Blue Line than South Station anyway), and the Blue Line (assuming a Blue-Red connector) offers much better transfer opportunities than an East-West tunnel to South Station would; such a tunnel would dump all of its riders on to the Red Line, who would then need to traverse the already-most crowded section of the line. Plus, South Station-Longwood Medical Area is a significantly more awkward journey than State/Gov't Center-Longwood Medical Area (and more on that in a second, too).
Yes...this is a big myth I've explained at length before. BLX's great hope is not the RUR-rapid transit connection. It's the fact that Lynn is a mega bus terminal and the linchpin of last-mile North Shore transit...but the bus service levels are historically effed because of the distended Wonderland + downtown runs down 1A every 4xx series route has to make, which wrecks equipment rotations to the point where all local routes end up frequency-starved. Greater than one-third of all of the 4xx's duty cycles are 'wasted' in the distended running miles. If you culled all @ Lynn Terminal like they used to be pre-1970 (before the T acquired the local bus carrier) the same equipment cycles can be recouped into >1.5x the last-mile frequenies everywhere from Point of Pines to Danvers & Beverly.
Is that not goddamn crucial for RUR growth alone? It's only half-cocked if bus frequencies persist forever at starvation level at Salem, Beverly, Swampscott, and others because of this systemic breakage. North Shore writ-large's transit shares will remain off-scale low compared to any other similar region (like South Shore) so long as the last-mile problem remains acute and unsolvable like that. Eastern Route frequency increases end up swimming against a headwind to bank their growth because the region-wide feeders not only stay capped low-frequency forever...but get worse with time as escalating 1A congestion chews more duty cycles. There's no other tactical nuclear strike project other than BLX that fixes this glitch with any efficiency. You can build a bigger Lynn Garage and stuff more Yellow-paint bodies there all the same; you still lose upwards of 33-40% of any fleet's duty cycles on the duplicating 'waste' miles.
Remember this. It takes more than one mode to tango a transformation. The RUR potential, no matter how great, still has one hand tied behind its back if the feeder buses are incapable of growing their frequencies. And incapable they will be until you build BLX. BLX arguably does more than RUR on the added one-seat utility because the giant expanse of swamp culls travel patterns from Lynn-proper to Revere not Chelsea...but even if you posit that the RR vs. subway modes can be pitted head-to-head at that task it's missing the entire point. BLX is the only multimodal kingmaker that flips all North Shore transit shares...to the very last mile...on its head. Nothing else.
Ultimately the goal here is to get all transit shares on the North Shore right-sized by taming the outsized car culture. That's only accomplishable by the megaproject that heals the bus breakage as part of its core proposition.
And that brings us to another drawback of a cross-tunnel routing -- it avoids a transfer node at Sullivan which can distribute Cambridge- and Somerville- (and maybe even Allston-) bound riders without going downtown, and it actually results in a trajectory that, overall, misses downtown much more than a Chelsea-Sullivan-North Station-South Station alignment would.
Yes. Maybe we need to highlight what a big effing deal the Urban Ring is going to be to clarify this, because it's challengingly abstract to parse out today vs. what we typically think of as Boston transit patterns. With full grade separation everywhere except for Chelsea St. lift bridge it's going to be a fast trip to go from Sullivan to Logan on a luggage-rack equipped Type 10 consist, with alternating 6-min. frequency filets between the Central Subway (Seaport/South End via North Station origin? Brattle Loop/GC origin?) and the Cambridge/Northwest Ring quadrant (Harvard Sq. origin?). Ultra-mega bus hubs like Sullivan & Harvard have never had such fast trips to Logan before. Kendall--such a very heavy airport-using audience--has never had such fast trips to Logan before. Likewise, with a hookup to a bus+trolley grade separated Terminal Transitway you can ensure that these are true one-seats to check-in/pick-up and not the forced transfer to some sort of shuttle that comes from any other trajectory including this NSRL addendum. Much like how the BLX-Lynn argument tends to get lost on the modal warfare singular tangent vs. the far huger multimodal coattails, real transformation comes first from full-court press across the spider map on more-dynamic service patterns first. Hence, the reason why our five-alarm most urgent projects are all radials and load-spread transfers...and not "route miles" for route miles' sake. The dynamism we seek comes from pushing a very different kind of distribution across the city.
When doing project scoring of these pitches you absolutely do have to weigh the monolithic "nice-to-have" against the more immediately implementable and multi-dimensional services along these high-leverage radial routes. It's not a bunch of 2D lines on a map going full steel-cage match against each other; what do the actual service patterns accomplish. We've discussed at length in the GL Reconfig/"Reimagined" thread that it takes some mental steps to perceive just how different and more dynamic the LRT system is going to be when both north hooks of the Urban Ring are built and cooking. These alternating run-thru patterns straight to the Terminals are excellent examples of that more "4D" dynamic and how it tickles the geographic spread. As one example...let's say you're a born pessimist about dispatching from Downtown to the Terminals on sustained 6 + 6 = 3 min. alternating headways . Well, when it's all interconnected there's nothing stopping you from adding a short-turn frequency of single-car trolleys solely between the Terminals and the BL Airport station so the thing is at full-on APM-level headways above and beyond the copious service coming from the west. Mind you, with SL1 still doing its thing on rubber tires shorn of carrying the water for excess intra-Seaport demand and saving buttload of time in its own right on the multimodal Terminal Transitway.
Tally up the full dynamic range of radial patterns you can unleash here, and then quantify how much is still left lacking from a cross-Harbor RR bore? It's still unfathomable that we arrive at anything "Paris-level" in overall airport centricity mandating that at anytime before second half of the century.
Third (and I'm surprised this hasn't been brought up yet): how exactly would things work at South Station in terms of that X-shaped network you've drawn?
[snip]. . .[/snip]
The reason this matters -- aside from the potential for an incredible amount of spaghetti under there -- is that you have to trade-off between the network comprehensiveness of "all trains everywhere" and the speed reductions incurred by crossovers, curves and capacity constraints. Plus, it impacts passenger journeys: you could mitigate some of that Red Line transfer crush if you can guarantee some x % of trains will travel Airport-Back Bay, Airport-Ruggles and Airport-Lansdowne, but again, that is going to entail a much more complicated build. (Plus, addressing the needs of incoming Airport riders impacts riders from the other direction as well, shunting away trains that might otherwise serve downtown more directly.
Very difficult, to be sure. Because the tunnel spaghetti makes all existing NSRL trajectories very precise slotting, while netting offset deep-cavern stations that no one would exactly call minimal-effort transfers for getting up/across to the Dewey Sq. concourse. It very much is what it is. Ditto with the Silver Line being a kinda rough shoehorn fit where its concourse sits amid all the infrastructure stacking. We haven't gone into engineering depth enough to place this would-be split spatially vs. the station platforms. But chances are overwhelming that even if it's possible it'll either take split before station onto dedicated SS Under platforms to the side at more station cost and less-efficient per-platform traffic utilization...or a crossover minefield just past the platforms imposing a capacity penalty. This is important as the Eastie bypass seems to be propping up the 2-track Congress St. alignment in quasi-aversion to the CA/T alignment. Any additional negative traffic impacts to only 2 tracks thru Downtown is going to hurt. And going to make the broad-based statewide sell job way harder because some regions will have to be prioritized over others and some regions may start being shut out from run-thru patterns. That critical-mass voting coalition is a lot harder to hold together @ 2 tracks vs. 4, so beware how much the bypass actually changes the project's fortunes from the core 2-track Congress vs. 4-track CA/T debate.
The infrastructure placement is pinned into born compromise by its surroundings. Actual results may not be as fluid as necessary to sidestep the whole straight-ahead mainline track capacity conundrum.