Crazy Transit Pitches

F-Line to Dudley said:
This proposal comes up often, and while seemingly rooted in logic in reality the opposite is true. The worst thing you could do for RL resiliency is to shove the branch split way down to Clayton St. and put Savin Hill on the mainline.

That's because there's still a Columbia Jct.; it's controlling the access to the car supply from Cabot Yard. Since the junction is more or less in an "X" shape with the "X" grade separated at the switches...the four arms of the "X"--subway/mainline, Ashmont Branch, Braintree Branch, and car supply via the non-revenue leads--are virtually impossible to all block/deadlock at once. That's crucial for the line that carries the most passengers on the system. The derailment hitting the signal cabinets was a one-in-a-million crippling shot, but for all the lingering damage from speed/spacing restrictions it did not physically shut down anything other than the Ashmont Branch. It didn't choke the subway's or Braintree Branch's car supply. In the 48 years Columbia Jct. has been there multiple arms of the "X" have been fouled numerous times by numerous types of incidents from minor disablements to major accidents to routine track work to the 2015 Snopocalypse. But the redundancy of the setup made it so that the whole system never crashed...the "X" never lost enough limbs that every single user was completely immobilized and that no trips were possible over at least partial tracts of the line.

If you have a mainline that extends to Clayton St. with the same Cabot Yard tie-in...it IS possible to completely paralyze everything Alewife-Braintree & Ashmont. Split a switch where the mainline and yard leads meet and...bang! Blockage between Andrew and JFK, branches both cut off from Cabot. Ill-time it where there's an imbalance of train supply Alewife-Andrew (maybe this happens on a Sat./Sun. when they're bustituting Harvard-Alewife for track work and that yard's closed), or where the yards are running empty on one of the branches. Now you have an extremely bad situation trying to round up enough cars to provide skeletal service to the nearest crossovers where trains can be turned around. If it's a really bad incident like a derailment that comes off the ground and can't be cleaned up next day PLUS Alewife Yard is empty because of that Sunday night track work shutdown...you don't have more than 2-3 trainsets to run the entirety of Monday subway service. As an acutely citywide-destabilizing event that's much worse and more economically damaging than last week's derailment, even though the crisis would be shorter-lived than our ongoing endurance trial.

In the end it's way less destabilizing to have at least 2 or more legs of the "X" still left standing in-service (even if reeling from a fried signal system) with ability to exchange car supplies than it is to have an outright break. Orange and Blue are capable of having outright breaks because they're mainline only (locations of their primary yards at the midpoints is a hedge against that). But while it hurts a real freaking lot when Orange or Blue go down for the count, not nearly as many trips are at stake there as if it could happen to Red (or Green, but that's even harder to knock out). So with Red being the line seeing the most continued growth and the most queasiness about future overload...we DEFINITELY don't want to mess with the Columbia "X". Just improve it with the next-gen signal system that'll be a lot more operationally resilient (within reason...a one-in-million KO hit from a derailing train isn't exactly a contingency one can easily plan for). They're planning to do just that, and just announced a major acceleration in that schedule.



I've got to search the board Archives for Old Colony double-tracking solves. Will post those next. It won't be cheap, but it's very feasible in Dorchester. Far more a question of will than way. Wollaston-East Braintree Jct. is the truly brutal stretch that doesn't have easy answers.
Click to expand...

But surely there are ways around this. Maintain three tracks for the Red Line as an extended yard lead to the Clayton St. junction and ensure the interlockings are designed for redundancy (basically replicate the X but with three tracks. It's basically a flying junction). Redo how cars are allocated during track work. Expand yard capacity at Alewife as part of an Alewife +1 to Arlington. The Orange Line operates in a similar fashion and seems to mostly get by fine.

Your position seems to be that it's impossible for the line to operate without unfettered yard access even in one-in-a-million situations. Surely the rarity of those situations means we can mitigate the downsides in them while capturing the benefits of the most common case?

EDIT: I took a shot at a track map for this and I think I see what you mean a little better now, but I'm still not convinced it's worth crippling the OC Lines for. The concern of one bad crash destroying the Red Line is present, but every other line we have has the same limitation. Honestly the solution is to acknowledge Cabot Yards are in a bad location and build more, redundant car storage elsewhere (or at least make better use of what storage we already have). The primary issue is with north of Cabot, but that's where we desperately need more anyway. Honestly just dig up Thorndike Park for one Winter, build some more tracks under that, and ensure there's allocations for an eventual Arlington expansion. All of the lines other than the Green have weirdly placed yards, and it's something they've had to deal with for a while.
 
Last edited:
ulrichomega said:
But surely there are ways around this. Maintain three tracks for the Red Line as an extended yard lead to the Clayton St. junction and ensure the interlockings are designed for redundancy (basically replicate the X but with three tracks. It's basically a flying junction). Redo how cars are allocated during track work. Expand yard capacity at Alewife as part of an Alewife +1 to Arlington. The Orange Line operates in a similar fashion and seems to mostly get by fine.

Your position seems to be that it's impossible for the line to operate without unfettered yard access even in one-in-a-million situations. Surely the rarity of those situations means we can mitigate the downsides in them while capturing the benefits of the most common case?
Click to expand...


Red needs more intensive mitigation than Orange or Blue; I stated that in the post. It carries far more passengers, sprawls far greater distance, and has branching. The midline yards on Blue/Orange also have bidirectional mainline access off the yard tracks. Red, because of Cabot's positioning, only has Columbia and the turnouts for reversing. Mitigation is legitimately more critical...more complex ops, higher stakes in an emergency. They are not comparable. Blue could've survived a switch-blocking derailment at Orient Heights because there's two sets of yard leads and interlockings spaced slightly apart. Red's got only one. There isn't an "optimize" ops solution around that by waving a wand and revamping practices. It's designed to operate a certain way, and that way shapes the ops.

If you want to gamble on that, be extremely careful what you ask for because stripping the Columbia redundancy too far back invites way more than just one-in-million events for knockout potential. Things that *have* indeed happened multiple times but haven't induced a total K.O. because of that fortified "X".

Tri-track to Clayton isn't going to fly either.

For one, you don't need to cut any redundancy through JFK to net space for a second Old Colony track. JFK busway reconfig doubles up the CR platform and a slight compacting of the Columbia flyover acreage[/] not layout does the trick for the "X" junction. Dual platforms + quad track preserved.

Second, merging branches with a third track doesn't do anything for resiliency because it's all same signal blocks and same power sections on all 3 tracks. Have a signal or power issue and both branches get severed all the same. Since Red isn't dispatched for overtakes-by-crossover like commuter rail it's little different from having 2 tracks.

Third, deleting only 1 track does not fix all that's wrong with the Savin Hill pinch. The OC needs a second track, but I-93 also needs a breakdown lane at the zipper merge to tame the chaos. -1 tracks doesn't help that. You need -2 to create space for all, which means either gamble on thin resiliency or stack 2-over-2 in a tunnel to preserve the current track layout. Like it or not, MassHighway has their finger well in this and any fix will have to accommodate some highway needs. Let's just hope it's only breakdown and merging fixes and not an outright lane capacity grab like they've made noises about in the past.


Alewife Yard is never going to be expanded, because any extension has to have its own yard. Arlington can't be a +1 to Arlington Center; the minimum ops-allowable is +2 to Arlington Heights with a larger storage yard behind the Arlington Lumber. Alewife Yard would go seldom-used unless the line were extended to Hanscom, where the yard's purpose would become a short-turning throttle-down for suburban headways.
 
Fine. I'll grant that if redundancy is the utmost goal beyond usable CR service levels for the entire south of Boston, then trimming the Red Line's rail allocation is not the optimal method for doing so, and that there is literally no mitigation that will ever alleviate the problem.

However, I don't grant the premise that the other lines are immune to the exact same issue that you claim would destroy the Red Line. If a train derailed at the wrong place in Wellington you'd be facing the exact same issue with most of the line being cut off. Yeah you could service Oak Grove to Wellington, but that's literally nothing for Orange Line service. Red carries a few more passengers, yes, but we're still dealing with tens/hundreds of thousands of people being impacted. The higher frequencies of the Red Line don't mean that the other lines should be okay with no service in the event of a disaster.

Or, and this was my point before, the other lines are getting by fine with their current yard locations, and the concept of a bad derailment crippling them isn't the end of the world.
 
ulrichomega said:
Fine. I'll grant that if redundancy is the utmost goal beyond usable CR service levels for the entire south of Boston, then trimming the Red Line's rail allocation is not the optimal method for doing so, and that there is literally no mitigation that will ever alleviate the problem.
Click to expand...

When did I ever say there was a preclusion of usable CR levels south of Boston???

  • I said the thrust of the Columbia acreage + JFK were eminently fixable with small touches requiring no track layout changes to Red. At most it's a nip/tuck of a *couple* of the flyovers' alignments to compact the geometry. And maybe not even that.
  • I said Savin Hill had proposed fixes. We've talked about them at great length on aB before. Sorry...I literally have not had time in the last 24 hours to Google that shit up into an explainer.
  • Wollaston to East Braintree Jct. is a FAR bigger limiter to CR frequencies, because the space isn't there at all and what partial fixes you can do are frustratingly limited in scope and regained capacity. If you want RER frequencies on the South Shore...stop worrying about fully-fixable Columbia and start worrying about the brutal dilemma on the middle- Braintree Branch.

However, I don't grant the premise that the other lines are immune to the exact same issue that you claim would destroy the Red Line. If a train derailed at the wrong place in Wellington you'd be facing the exact same issue with most of the line being cut off. Yeah you could service Oak Grove to Wellington, but that's literally nothing for Orange Line service. Red carries a few more passengers, yes, but we're still dealing with tens/hundreds of thousands of people being impacted. The higher frequencies of the Red Line don't mean that the other lines should be okay with no service in the event of a disaster.

Or, and this was my point before, the other lines are getting by fine with their current yard locations, and the concept of a bad derailment crippling them isn't the end of the world.
Click to expand...
Look at Wellington's yard access: (1) wye tied in by 2 interlockings north of station w/ crossovers at each wye leg to all 3 mainline tracks ; (2) 1 interlocking w/ backup crossovers south of station accessible to all 3 mainline tracks. Interlockings on (1) separated by 600 ft. (1) and (2) separated from each other by 2100 ft. The only way physically possible to paralyze Wellington with all that separation is to fry the electrical substations for the whole area, which are at the MOST redundant here vs. anywhere else on the mainline because of the extreme power demands of running a yard w/ major maint facility.

Orient Heights' yard access: (1) wye tied in by 2 interlockings north of station; (2) 2 additional tracks on the inbound-direction wye side tied into a wholly duplicate interlocking + crossovers to the wye; (3) flex storage track tied in south of (1) and (2). Wye interlockings are 500 ft. apart. (2)'s interlockings are stacked right next to the inbound wye's interlockings. A bit more vulnerable than Orange because it's all stacked north of the station; (2)+(3)+inbound wye on (1) are all within a train length's closeness; and the pocket track on (3) doesn't tie into the main yard as an alternate escape in a yard blockage. But there's still triple-or-quadruple redundancy in the interlockings. Enhancements may be coming here soon reconfiguring the yard access because the Blue climate resiliency study is zeroing in on Orient Heights fortifications in case they have to evacuate the fleet to safety ahead of a major storm surge.

Red: flyovers from Cabot to each branch and reversing crossovers into the subway. That's it. It relies on the grade separation on each leg of the "X" for the redundancy. It is very different from the other two because there's only one reach from Cabot to tie it in. If this is not fully obvious from the Google linkies, then I don't know what to tell you. They're not the same.


Further, it's not "a few more passengers". It's 70,000 more daily passengers than Orange (34% more), 210,000 more than Blue (331% more), and 51% of the systemwide HRT ridership by its lonesome. Degrees of not-okayness in a major disruption are extremely more severe for Red than if Orange or Blue suffers the same fate. They're pretty goddamn severe if they do happen on Blue or Orange, but by the numbers it is nothing compared to how all-world disruptive a Red meltdown is. Red is in a whole other universe than the others in how much resiliency matters. Under no circumstances am I arguing that it doesn't matter for Orange or Blue...but I am arguing against your assertion that Red is somehow interchangeable in impact to the rest. It's so very not.
 
F-Line to Dudley said:
When did I ever say there was a preclusion of usable CR levels south of Boston???

  • I said the thrust of the Columbia acreage + JFK were eminently fixable with small touches requiring no track layout changes to Red. At most it's a nip/tuck of a *couple* of the flyovers' alignments to compact the geometry. And maybe not even that.
  • I said Savin Hill had proposed fixes. We've talked about them at great length on aB before. Sorry...I literally have not had time in the last 24 hours to Google that shit up into an explainer.
  • Wollaston to East Braintree Jct. is a FAR bigger limiter to CR frequencies, because the space isn't there at all and what partial fixes you can do are frustratingly limited in scope and regained capacity. If you want RER frequencies on the South Shore...stop worrying about fully-fixable Columbia and start worrying about the brutal dilemma on the middle- Braintree Branch.
Click to expand...

And eventual service levels will require double tracking of the entire length.I'm not talking about double tracking Columbia Junction, I'm talking about double-tracking the entire single-track segment from Neponset to South Station. Of course we need to solve other single-tracked areas, but to solve the overall problem we need to solve each individual one.

I'm aware of the Savin Hill proposals. I'm dubious that much tunnelling is going to fly anytime soon.

Look at Wellington's yard access: (1) wye tied in by 2 interlockings north of station w/ crossovers at each wye leg to all 3 mainline tracks ; (2) 1 interlocking w/ backup crossovers south of station accessible to all 3 mainline tracks. Interlockings on (1) separated by 600 ft. (1) and (2) separated from each other by 2100 ft. The only way physically possible to paralyze Wellington with all that separation is to fry the electrical substations for the whole area, which are at the MOST redundant here vs. anywhere else on the mainline because of the extreme power demands of running a yard w/ major maint facility.

Orient Heights' yard access: (1) wye tied in by 2 interlockings north of station; (2) 2 additional tracks on the inbound-direction wye side tied into a wholly duplicate interlocking + crossovers to the wye; (3) flex storage track tied in south of (1) and (2). Wye interlockings are 500 ft. apart. (2)'s interlockings are stacked right next to the inbound wye's interlockings. A bit more vulnerable than Orange because it's all stacked north of the station; (2)+(3)+inbound wye on (1) are all within a train length's closeness; and the pocket track on (3) doesn't tie into the main yard as an alternate escape in a yard blockage. But there's still triple-or-quadruple redundancy in the interlockings. Enhancements may be coming here soon reconfiguring the yard access because the Blue climate resiliency study is zeroing in on Orient Heights fortifications in case they have to evacuate the fleet to safety ahead of a major storm surge.
Click to expand...

Hm. I'll grant I was unaware of the omni-directional yard access for both.

Red: flyovers from Cabot to each branch and reversing crossovers into the subway. That's it. It relies on the grade separation on each leg of the "X" for the redundancy. It is very different from the other two because there's only one reach from Cabot to tie it in. If this is not fully obvious from the Google linkies, then I don't know what to tell you. They're not the same.
Click to expand...

The fact that Cabot only connects to one direction of the Red Line (both with the single reverser) should be all the more reason to look for upgrades here. Ari's proposed fix is part of what spurred my question, but I was curious if similar effect could be obtained without relocating a massive facility and construction of a new one from whole cloth.

Further, it's not "a few more passengers". It's 70,000 more daily passengers than Orange (34% more), 210,000 more than Blue (331% more), and 51% of the systemwide HRT ridership by its lonesome. Degrees of not-okayness in a major disruption are extremely more severe for Red than if Orange or Blue suffers the same fate. They're pretty goddamn severe if they do happen on Blue or Orange, but by the numbers it is nothing compared to how all-world disruptive a Red meltdown is. Red is in a whole other universe than the others in how much resiliency matters. Under no circumstances am I arguing that it doesn't matter for Orange or Blue...but I am arguing against your assertion that Red is somehow interchangeable in impact to the rest. It's so very not.
Click to expand...

I was not arguing that the Red Line is just another line. I was arguing that the other lines are also important and just as critical for the communities they serve. Given the yard track layouts differed from my previous understanding, I was wrong on how redundant their systems actually were, though.
 
jbray said:
F-Line, What is your take on Ari's proposed fix for the yard and flyovers?
Click to expand...

Ari apparently is unaware that Google has a Terrain View.

The relocated storage yard:
118hct2.jpg


The relocated maint facility:
33w0ide.jpg



Yeah, oops. Can't do anything on top of a geologically unstable trap rock seam of wildly varying elevation, even if you could somehow weave tracks (which he also didn't explain) to that spot. The whole piece collapses right then and there from basing all on this faulty assumption.


The piece has many, many other problems.

  • He cites the existence of a mid-line yard as one of the "four major problems", but does not attempt to explain why Orange, Blue, and Green (Reservoir) operate with exactly the same setup. Or why they are common in New York, Paris, London, and so many other HRT systems for the same ops reasons.
    • This is not much different from his bus piece where he advocated for kicking bus yards out to 128 in Weston and Woburn, when in most cases the bus yards are by-design in close range of the nearest major bus terminal. Ops factors dictating such placement like minimizing systemic non-revenue cost losses he was genuinely un-curious about. It was all about land-grab for me, land-dump for thee.

  • He says the switches are too complex as a bad thing without positing what simplifying them would mean for ops. As mentioned in my last post, Orange/Blue/Red ALL have multiple yard interlockings for redundancy's sake. That's an intentional design feature. And those other worldwide systems all do it too. So if the gateway to this piece is that Red failed on resiliency during the derailment, you must explain how REMOVING interlockings that so many world systems install explicitly for resiliency's sake somehow enhances resiliency or does not actually matter for it. This needs some bare minimal attempt at explanation, however meek or misguided.

  • "Valuable land". This is non-sequitur for a train ops piece. But it's also a non-sequitur for the Cabot acreage because the northerly 400,000 sq. ft. are already provisioned for air rights builds for anyone who wants them. The land itself is below most of the street grid and inaccessible from anywhere except Foundry St., making its value proposition at ground-level problematic. As with the Braintree Split storage yards FAIL, he seems to be having trouble seeing things in 3 dimensions.
    • This is pattern and/or obsession with him. In his equally flawed bus yards piece he stanned for the south tip of the Wellington parking lot as extremely valuable space that had to be built on even though there was only one possible very constrained egress out, and would not consider any arguments about how access demerits affect land value. All slabs of earth in crow-flies distance to "important" things are equally valuable.

  • He cites "not even close to said line" while simultaneously providing a link-out to exactly why the Cabot site had to be chosen way back when. Cabot was an extremely polluted ex- NYNH&H RR coach yard that, as today, was below street level to the entire grid excepting Foundry St. and abutting the commuter rail tracks. No one in 1970 was going to clean up all the pollutants except for the T, and it's pre-provisioned with capacity to load-balance supply with the outer yards up to and including a Hanscom/128 extension. It's abundantly clear why that site was chosen. And why does its length have anything to do with ops when it's the means of tie-in that dictates its usefulness, and the land for the yard leads simply travels along Amtrak Southampton Yard and the commuter rail's Widett Circle shoplet for the majority of its length.

  • Putting the main storage yard and maint facility on 1 branch only is suicidal for resiliency. This is another fundamental misread or uncuriosity of how ops actually work, compounding the criticism of mid-line yards. The Braintree Branch was KO'd for weeks by Snowpocalypse '15. Everything he was attempting to shove on top of the rock rubble pile at Braintree Split would've been isolated the whole time, leaving too little equipment to run the subway at more than 20+ minute frequencies...for an entire month. As it actually happened the Cabot leads were kept clear as a priority, and the subway was fed at manageable delays that quickly diminished while the branches lingered in deep freeze. I mean...where are you going to get the Snowzilla melter machine to clear the Longfellow Bridge when it's stranded 9 miles out in Braintree??? The obvious logistical flaws here are really not that hard to tally up.

It's a shockingly ill-informed piece by his standards. I dunno...coupled with the bus piece he's got some real bug up his ass about storage yard land usage that he can't seem to coherently articulate, and so it comes out as this mismash of contradictions from unrelated ops, land planning, and aesthetics realms. Even Alon Levy gave it to him good on Twitter over the faulty assumptions in the last bus yard piece. This RL one has far obvious whoppers, starting with the Terrain View FAIL but then stubbing its toe left and right on all manner of other things.
 
Thanks F-Line! Is there any reason why Cabot is not connected to Broadway north other than the proximity to the channel? What about flying junctions around/under the Andrew area?

My other ask here is could the split heading north be five tracks with three red, two commuter rail almost like Haymarket north and have approximate functionality with the current Columbia junction?

I guess in my mind, if the geometry is available to merge Ashmont/Braintree earlier, a junction, wye, or some combination becomes much more practical for Columbia because you are no longer using one spot to handle the yard and branches simultaneously.
 
jbray said:
Thanks F-Line! Is there any reason why Cabot is not connected to Broadway north other than the proximity to the channel? What about flying junctions around/under the Andrew area?

My other ask here is could the split heading north be five tracks with three red, two commuter rail almost like Haymarket north and have approximate functionality with the current Columbia junction?

I guess in my mind, if the geometry is available to merge Ashmont/Braintree earlier, a junction, wye, or some combination becomes much more practical for Columbia because you are no longer using one spot to handle the yard and branches simultaneously.
Click to expand...

Cabot was built in 1971, so it postdates the SS-Andrew subway by 50+ years. The yard leads are also nowhere near the subway until Boston St. crosses above very near to the subway portal. There was no possible interface from the yard to the subway without razing blocks of Dot Ave. buildings that at that time still had some substantial industry in them.

That area of Dot Ave. is getting too built up for other reasons today to attempt similar, so Columbia is always going to be the insertion point. Subway is all cut-and-cover here so tying leads in would require lots of surface disruption.

I explained in one of the previous posts why tri-tracking is a critical loss of redundancy. Orange-north has all 3 tracks on the same signal blocks and signal plant, and a Red consolidation for the branch split would do the same. Delays due to "switching problems" (or worse) would gum up or KO access between branches and mainline...and you'd notice the difference on the mundane crap like "switching problems". The total separation between each arm of the "X" means Braintree is insulated from a same-spot problem on Ashmont. It would not be a good idea to go less than 2 x 2.


Now, for Savin Hill it's not a horrendous expense to bury Braintree under a surface Ashmont to free up 2 surface CR tracks and some 93 shoulder width. It would be like a Wellington tunnel...cut with bare tunnel roof supporting the Ashmont tracks. Problem is MassHighway completely highjacked the process and asked for TWO new managed lanes on 93 in addition to the 8 travel lanes, forcing commuter rail to also be buried in a bigger tunnel with active ventilation. Thus tripling the price and making it a naked car capacity grab. Doesn't have to be that boondoggly...but the auto interests will have to be thoroughly put in their place.
 
Here now are some pictures of what could happen with Savin Hill.

Current Conditions (from FCMB presentation)
30n82dg.jpg


--------------------------------------------------
MassDOT South Coast Rail Proposal (from FCMB presentation)
2302e1.jpg


It is, in a word, abomination. TWO lanes added to 93, and they attempt to bury commuter rail too...which requires much larger-dimension tunnels and an active ventilation system for diesel exhaust (needed even in an electrification universe for un-electrified Hyannis trips, freight, and non-revenue trips to the commuter rail work yard in Rochester). Easily a billion-dollar project, three-quarters of the cost a direct consequence of the car capacity grab.

--------------------------------------------------

No Highway Capacity Add Minimal Tunneling Version
I did some shitty Photoshopping of the above two to come up with this.
j9wntd.jpg


Deletes all the cost blowouts of the car-centric design by keeping CR on the surface. At -1 surface track berth and some compacting from redesign of the Savin Hill Ave. overpass abutment placement (has to be done with any scheme that moves things around), can grant 93 much more substantial (if not quite 100% Interstate-standard) breakdown lanes while otherwise leaving its capacity stet. Construction phase much easier to swing with only individual track outages required...not doing temp lane shifts to tear up whole tracts of highway. Expense is as low as it'll get for preserving Red Line capacity in an explosive growth era while adding RER capacity to the Old Colony. RER can probably sell the idea in a way that HOV lanes just can't in 2020 no matter how many times MassHighway tries to relive its greatest hits of the 1990's.
 
^I like it, buy you forgot to include the gantries for automated electronic tolling on 93
 
Possibly a stupid question: is there any value to cut-and-covering four tracks, putting the Ashmont branch underground as well, and laying four tracks for RER/commuter rail on the surface? Or putting electrified RER in a tunnel? Basically, four T tracks, four rail tracks, in some combination.

I imagine that 1) Old Colony lines don't need four tracks, and 2) rebuilding Savin Hill station isn't worth the expense, but I was curious about the possibility...
 
jlichyen said:
Possibly a stupid question: is there any value to cut-and-covering four tracks, putting the Ashmont branch underground as well, and laying four tracks for RER/commuter rail on the surface? Or putting electrified RER in a tunnel? Basically, four T tracks, four rail tracks, in some combination.

I imagine that 1) Old Colony lines don't need four tracks, and 2) rebuilding Savin Hill station isn't worth the expense, but I was curious about the possibility...
Click to expand...

1) Correct. The OC doesn't need quad to hit RER service levels (and maybe some quasi-Urban Railish short-turn frequencies to Brockton). The last time it used 4 tracks for passenger service--through about 1938-40--it had many more than just 3 branches to feed plus a lot of additional pre- Red Line era stops inbound of Braintree. I think it might be a few pages up in this thread, but I also did an explainer of why formerly quad-track mainlines now have equal-or-better capacity as double-track mains (NEC excluded) because of modern bi-directional signaling.

2) Correct. It's extremely light ridership, was just rebuilt in 2005, and doesn't need to be demolished to accomplish project goals of creating room for the CR capacity, preserving Red Line resiliency, and increasing I-93 resiliency with fuller-size shoulders. The Wellington Tunnel-like Braintree cut-n'-cap can even swerve out of the way of the platform footings at zero structural peril, so the '05 station shouldn't need to be touched once during construction. The only justification for burying all of Red is the same as it was for the state's insane render burying Braintree + CR: humongous add-a-lane(s) grab for 93. Which should be violently opposed on sustainability principles alone. Therefore: 2 tracks of burial only, and Braintree not CR if you want a tunnel that's going to stay slim on cost (i.e. smaller-dimension cut, no ventilation system required*).


*Mentioned in previous post, but you'd need a ventilated CR tunnel here even if revenue service runs electric because there's CSX freight rights through here, diesel-hauled T work trains use this route to reach the remote Rochester facility, and Cape Cod will likely be a diesel malingerer for many years if not forever.
 
Picking up on the "Aqua Line" discussion from the Unbuilt Roads thread... There's always the question of where the Blue Line heads after the "Reasonable" expansion to Kenmore, and I'd like to make my crazy pitch for BC.

Blue would tunnel under Brookline Ave with new stops replacing the D line at Park Drive and Longwood Ave. Portal up to the existing D line at the baseball field/parking garage, continue to upgraded BV, BH, and Beaconsfield until tunneling off the ROW and into a Chestnut Hill Ave/Comm Ave tunnel to BC/Lake St station location with space to reverse under the existing yard (assuming this would be feasible/similar to the proposed Longfellow tail tracks?).

This, of course, requires massive changes to the Green line.
The outer D line would connect over to the existing C, which is tunneled all the way under Beacon from Kenmore to the baseball field where it gets back on the D ROW to Chestnut Hill and beyond. Cleveland Circle serves both Blue and the C in an underground transfer station. Remaining C stops are at Washington Sq, Coolidge Corner, and Audubon Circle with bus lanes on Beacon replacing the closed stops. B line would run to Cleveland Circle on the surface.

Combining C and D frees up space for restored Brighton/Oak Sq services, a new Harvard branch, or Grand Junction/other Urban Ring service (all merging in a Comm Ave tunnel before Kenmore). Would also improve trip time for Needham/Riverside riders with a straight shot into Kenmore. Having to transfer for Longwood/Fenway would be negated by improved station locations in the Brookline Ave tunnel. D ROW from east of BV to Kenmore could be preserved for future service or returned to parkland.

Maybe this could happen if BC wanted to seriously buy-in to a project that dramatically speeds their access to Longwood, downtown, the Airport, and an easy transfer to Cambridge? Or if Brookline ever wants to give up on having surface stops every 500ft :lol:. Lotta $$$ for no real expansion of service, but the reliability and redundancy improvements could make it an intriguing option at some point in the next 150 years or so.
 
Is it possible to build a pedestrian tunnel connecting the Somerville community path to the alewife linear path crossing mass ave or are the red line tunnels too shallow.
 
Last edited:
dmdogs900 said:
Is it possible to build a pedestrian tunnel connecting the Somerville community path to the alewife linear path under mass ave or are the red line tunnels too shallow.
Click to expand...


They already direct-connect at Alewife, so there'd be no need to do it elsewhere.


Porter-Alewife has long been a path possibility, but City of Cambridge has never come to consensus on where the track-spanning footbridge would go.
 
Last edited:
You must log in or register to reply here.

Back
Top