Regional Rail (RUR) & North-South Rail Link (NSRL)

George_Apley

Not a Brahmin
Staff member
Joined
Jan 22, 2012
Messages
4,632
Reaction score
1,025
Are we doing this in this thread too? Blowing up Boston's transit environment by *getting rid of* North Station is Design a Better Boston fodder.
 

F-Line to Dudley

Senior Member
Joined
Nov 2, 2010
Messages
6,404
Reaction score
1,273
Building over a railroad tracks is MUCH more expensive than building on open land. That is what held up South Station and the air rights over the Pike. My suggestion of eliminating North Station also eliminates the cost of building over the tracks, and makes the land more valuable .
Who says Jacobs' land is even *mostly* over RR tracks like the 100% stilts job at South Station? Look at the slabs in question on Google, bisected by the cutting Leverett ramps. NS ≠ SS by a million degrees.

Backside of the Garden has slack space for 3 island platforms' worth of westward expansion should Draw 3 get reinstated...but that all ends a full 125+ ft. set back of Nashua St. Jacobs has a perfect rectangle fronting Nashua, north of Leverett ramp, stretching through about 3/4 of the footprint of the expendable ex-Spaulding building that nets 115K sq. ft. no air rights whatsoever...all at ground level. That's already bigger than the Hub on Causeway by a large measure, without engaging a single track's worth in the air. It's only when widening the rectangle on the backside that design considerations go into play for a partial back porch spanning some of the tracks. If you maxed out the entire back space to the contours of the Leverett ramp you net >200K sq. ft. of buildable space, but only a maximum of 35-40% of it has to pass over any tracks. Now, it's highly unlikely anyone would ever go for the max-out because the ramps contour it to pretty irregular shape by the curve in the road. The most 'buff' anyone would ever choose to go with the back porch is maybe a smaller rectangle behind the Nashua-facing one...50K sq. ft. of track overhang tops. Tops...with the sliding scale most likely favoring a much smaller porch.

The other parcel behind the Garden NE corner is a sloppy-seconds pinned in by the ramps and Big Dig vent shaft with claustophobic-at-best driveway access. At most a 50K sq. ft. slab entirely on-stilts, but the access problems would practically necessitate something much slimmer than that. And only after the Nashua St. frontage and any back-porch overreach is finished, because the Nashua access is so incredibly higher-leverage. So the parcel that is an actual SS Tower analogue is the last that will ever be developed here...if it's developed at all.


Lastly...a repeat: Jacobs is the oracle here, not punter's logic. He's not getting any younger, and so if he wants one last career capper he's going to move on the Nashua-facing parcel decades sooner than NSRL. Including back-porch considerations if that's a reach worth going for (but also maybe not). The argument for a zero-out of the surface terminal--already a weak one for the egress defaults on the likeliest tunnel Alt. and the scheduling punctuality standard such a blended system is shooting for--will be that much more weakened by the increased demand fueled by infill development Jacobs has sole rights to here. With or without it spreading onto a large porch, short porch, or no porch. Beware what wormholes our integrity-of-concept target fixations are leading us down. If it's that much easier on ops fluidity and demand to take a pass on touching the pre-existing station, then somebody's idea of zero-out perfection has a very tough hill to climb on self-justification. ^This^ is one such example, because when we say "air rights" we're talking an extremely different (nay, optional if the dev so chooses) maximum scope than SS air rights...but still a quite huge amount of transit demand-generating development putting its hand on the scale. It doesn't take a perfectly clear picture to keep NS Surface; rather, it's going to be the default hedge and fungible do-no-harm choice unless the zero-out schemes can overpower the argument with self-perfection. I just don't see where zero-out is going to score such an utterly perfect self-contained argument in light of the ops-punctuality considerations and what's likely to be built for new demand generation here. It's competing against very few downsides on leave-it-be.
 
Last edited:

StillInTheHood

New member
Joined
Feb 19, 2013
Messages
24
Reaction score
24
Separate from the issues that F-Line covers above, I think we've lost sight of the objectives again. "North Station" obviously still needs to exist in some form, because the Orange/Green transfer is absolutely critical. In the absence of NS Surface, we are again stripping out platforms that can be used for short-turns, recovery and balance, and we are forcing every train, even long-haul Downeasters and future New Hampshire service into the expected-to-be very busy tunnel. At the risk of repetition, we again need to look at how successful RER systems operate in the real world. Some of the Munich S-Bahn lines need to manage around freights, too, believe it or not ... the "wobble" that F-Line describes is dealt with via LOTS of sidings and passing tracks. And as previously discussed, their system is built with lots of short-turn capacity.

Not long after NSRL is built, there will come a day when the tunnel is either inaccessible for a meaningful period of time during rush hour, or reduced to one track - perhaps there's a signal problem, a switch problem, a disabled train, an idiot who got onto the tracks, etcetera. It's not an everyday occurrence, but it's not THAT infrequent. There are backups of different durations in the Munich tunnels literally every week of the year.

Now what? When this happens in Munich, they short turn trains as necessary, making use of ample platform capacity at stations like Ostbahnhof, where there is good U-Bahn and bus access, as we also have at North Station/Haymarket. They logically prioritize certain lines (such as the airport line, unsurprisingly) and force other commuters to change trains. Obviously commuters grumble a bit when this happens, as the trains are more crowded, and some passengers bail altogether onto the U-Bahn. North Station would work similarly - if there's a problem and the trains need to terminate there, north side commuters can switch to the Orange Line to access Back Bay as they did in the old days. Not ideal, and subways and through trains get more crowded when there's a system hiccup, but it's not a catastrophe. The short-turned trains are often able to approximate the original schedules, and when the problem is resolved, recovery is quite quick. A bunch of people may be 20 minutes late to the office, but they've forgotten about it by lunchtime.

How is this going to work here without NS Surface? Imagine inbound trains on every single northside line with literally no place in the city to go. Even if the problem is deeper into the tunnel and NS Under is still accessible, there won't be capacity to turn all the inbound trains there, unless we are replicating a bunch of extra platform capacity underground, which would cost a bundle and defeat the supposed purpose of eliminating the existing surface station. So ... ??? I suspect the default would be to cancel a bunch of trains in advance and a whole lot of waiting on all the inbound lines enroute. Maybe if you are on the Fitchburg line you'll be lucky enough to be short-turned at Porter, where at least there's a Red Line connection. Otherwise, though, I'd expect a bunch of very pissed off commuters to be stuck for an indeterminate period of time at remote stations, or, even worse, between stations. Schedules would still messed up hours after the problem is cleared. People end up being hours late, and they not only remember it at lunchtime, they are still pissed about it the following week. A multi-branch system with :15 headways that goes through a central tunnel can get bottled up really, really quickly. And when the end stations are more than 40 miles from the city center - much longer than the longest Munich S-Bahn line, BTW - any little whoopsie leads to a conga line of traffic that needs to be dealt with immediately and efficiently by the ops team.

If you haven't experienced an RER system like this on an everyday basis, as a thought exercise imagine if the Green Line couldn't turn at Park Street or Government Center or reverse at Kenmore ... and instead of ever hearing "sorry, this train is being taken out of service" at Park Street, every single time that situation happened you were instead summarily dumped at Brookline Village or Boston University or Audubon Circle or Brigham Circle and left waiting for a recovery bus. Now imagine that 10x worse, since these heavy rail stations are more remote and much further apart and it's more of a logistical challenge to hurry buses to them. In the present day, we ALREADY see blips causing ridiculous backups on the existing MBTA commuter rail even with infrequent headways and without a tunnel ... we'd just be ensuring our legacy of brittle service continues exponentially into the future.

So North Station surface stays. As for its theoretical future best configuration and how many platforms it requires, I leave that to F-Line and engineers that know a lot more about this than I do. (All of this, BTW, is also why a 4-track tunnel would conceptually be better than a 2-track tunnel ... the latter is inherently brittle even WITH ample short-turn provision on both ends).
 

F-Line to Dudley

Senior Member
Joined
Nov 2, 2010
Messages
6,404
Reaction score
1,273
So North Station surface stays. As for its theoretical future best configuration and how many platforms it requires, I leave that to F-Line and engineers that know a lot more about this than I do. (All of this, BTW, is also why a 4-track tunnel would conceptually be better than a 2-track tunnel ... the latter is inherently brittle even WITH ample short-turn provision on both ends).
Tunnel stations would be constructed as such:
  • Station bores are 2 tracks each just like the mainline. On the 4-track unified CA/T bore you'd have semi structural separation of Tks. 1 & 2 from Tks. 3 & 4 at each of the stations.
  • Each 2-track station bore would have 1050 ft. Northeast Regional max-length side platforms 16 ft. wide...and also a center platform 30 ft. wide between the 2 tracks so all doors can open at once. All-doors/both-sides boarding is crucial for retaining TPH throughput in very constrained spaces, because these platforms will be narrow for the intense amount of projected foot traffic. Center platform is where hop-on transfers are most easily facilitated.
    • 16 ft. wide side platforms are wider than T-minimum spec 6 ft., and 30 ft. center platforms are wider than T-minimum spec 12 ft.
  • 3 egresses per station...at ends and center of platforms
  • Mezzanine right upstairs atop the roof of the bore for quickly switching side platforms, or changing from one 2-track bore to the other 2-track bore for the 4-track C/AT builds. You do not have to go all 100 ft. up to the top unless you're changing to rapid transit or surface.
  • Central Station on the CA/T alignment is constrained. Platforms will sit on a slight grade (within ADA tolerances), and will be 800 ft. maxi-T length instead of maxi-AMTK length.

Earlier scoping studies tried a track fan-out instead with 4-track mainline tunnel spreading into 6-8 SS + NS platforms and up to 6 CS platforms for traffic-managing platform dwells. That did not prove feasible, because the only way to make it work was to go with minimum allowable width platforms w/ one-side doors only...and that simply wasn't good enough for managing the boarding/alighting foot traffic. It actually worsened dwells vs. cutting the track margins but fattening the platforms, and the crossover games that had to be played at the fan-outs/mash-ins flanking the stations brought throughput back to par despite the extra tracks.

Keep this in mind, because there is no effing way you're short-turning on-platform anywhere in the tunnel, as that effectively takes 1 whole track of tunnel out-of-service while you're pulling the reverse. Also...2-track only build has very reduced throughput in a disablement or late-running slot so practically we're going to need the resiliency of quad-track in lieu of having any turnouts. And this is going to throw lots of cold water on anybody's dreams of getting rid of NS Surface, given that punctuality has to be immaculate and pairing rotations rationed to good balance to keep dwells from overspilling very tight margins. Deviations from average pairings are really going to need to be prioritized for surface dumps.

In short...we did learn a lot in 20 years about what makes an underground thru station...and it's some bit of good news (Japanese best-practice scheduling + not cutting egress flow to the bone) and some bit of bad (no room for extra turnouts and dwell-safety slack within the engineering constraints, because wider-than-minimum egresses are too critical for throughput). Plot accordingly on what features you're gung-ho to cut vs. hold the line for.
 
Last edited:

tysmith95

Senior Member
Joined
Feb 8, 2016
Messages
2,637
Reaction score
105
Crazy transit pitch: put I-93 through downtown on a diet, have trains run through that tunnel.
 

F-Line to Dudley

Senior Member
Joined
Nov 2, 2010
Messages
6,404
Reaction score
1,273
Crazy transit pitch: put I-93 through downtown on a diet, have trains run through that tunnel.
Wouldn't work. The grades on 93 are too steep and meandering for rail. Drive it NB and see how right at the bottom of the incline you've got the curve + sudden upslope after the first merge. That's a definite no-go for rail grades.

Plus the highway level leaks like a sieve. The one thing the lower-level dig will have going for it is that the bare slurry walls will be properly sealed with a regular old inner lining to keep it groundwater-tight like a normal tunnel. On the highway level they're unsealed in order to fit the same lane width on-footprint as the old surface Artery. The bare slurry wall leaks are supposed to be a "feature" mitigable through regular maintenance, but the Big Dig engineers underestimated just how much it would leak so the annual maint cost chew is way higher than anticipated. That thankfully will not be a problem on the rail level, 2-track or 4-track CA/T alignment.
 

Top