If You Were God/Goddess | Transit & Infrastructure Sandbox

[F-Line to Dudley]

Add 2 more tracks, a central station, and more portals for the OC/Fairmount lines and the cost nearly doubles.

No it doesn't. You're reading from Baker's tankapalooza '18 study that said the only way to get 4 tracks and OC/Fairmount participation was to build the CA/T alignment wholly duplicate to the Congress St. alignment, which is an abso-fuckin'-lutely bonkers claim so incredulous it disqualifies the whole study. Double-boring one route doesn't double the cost, no matter what that awful study (which also lumped in all of the electrification costs we're supposed to be doing separately and sooner) claims.

 

[TheRatmeister]

Double-boring one route doesn't double the cost

No, but double-boring, doubling the number of portals, adding a third station, and making the stations twice as large will at minimum get you a hell of a lot closer to 2x the cost. The "full build" would basically be East Side Access but with three 120ft deep stations instead of one, so expecting anything significantly under the $11 billion cost for that project is probably a pipe-dream.

 

[Tallguy]

No, but doubling the number of portals, adding a third station, and making the stations twice as large will at minimum get you a hell of a lot closer to 2x the cost. The "full build" would basically be East Side Access but with three 120ft deep stations instead of one, so expecting anything significantly under the $11 billion cost for that project is probably a pipe-dream.

F-Line, should I hold your beer or do you want to hold mine?

 

[ritchiew]

@BosMaineiac that all sounds about right, but a couple of things

the central artery tunnel is too steep for FRA grade requirements

The north and south entrances to the tunnel are too steep. But I think everything in between (basically Summer Street to North Washington) is under 3%, which is what the FRA was allowing in other NSRL plans. If @Hooledeli 's plan is to tap into the tunnels just north of South Station, the grades are fine until a bit past Haymarket. (What happens then, I don't know what they have in mind)

the current tunnel would be unable to achieve the necessary height clearance

I don't think this is right. The ceiling you see in the tunnels are just panels covering a massive open space for ventilation. It could be possible to raise or remove the panels to accommodate a train. More details here, if you're interested.

The second point is that the foundations beneath south station preclude any sort of tunneling. When they rebuilt the bus terminal in anticipation of the (now largely completed) south station tower they built very deep foundations beneath the existing platforms, between every pair of tracks. The original NSRL plan had utilized the same route as you’ve shown in your photo, but after the SS rebuild, it was determined to be infeasible. That’s why the most recent MassDOT NSRL study had an alignment along fort point channel, which will provide vertical and horizontal clearance from south station to the new underground station

Yeah, I keep wondering about that. Is there some study where they definitively say it's no longer possible to tunnel under South Station? The foundation for the new tower is all east of tracks 1-4, so I've wondered if it would be possible to tunnel just under those tracks (but I also have no idea what the foundation for the bus terminal looks like). Basically, there's this diagram from a NSRL proposal back from the Big Dig days, with 4 tracks directly under South Station. That can't be done anymore, but I wonder if the western two tracks are still possible.

 

[F-Line to Dudley]

No, but doubling the number of portals, adding a third station, and making the stations twice as large will at minimum get you a hell of a lot closer to 2x the cost. The "full build" would basically be East Side Access but with three 120ft deep stations instead of one, so expecting anything significantly under the $11 billion cost for that project is probably a pipe-dream.

Again...they sandbagged it with billions in electrification and dual-mode rolling stock costs under the assumption that we would not be doing Regional Rail sooner. Regional Rail is a necessary first gear to densifying service before there's even an actionable mission statement for building the tunnel, so the fact that they tipped the scales under an assumption that we would not be doing it sooner is the tell that the study had one goal: tank the whole project forever.

Subtract the electrification and rolling stock costs and it's $6-8B, which is about in line with what the FTA was scoring the project as prior to Baker putting two hands around the project's neck (and I'm being generous...the 2017-inflation-adjusted-to-2025 estimate was $4-6B). It's nowhere near ESA-level bad...nothing else in the whole world is ESA-level bad.

 

[TheRatmeister]

Subtract the electrification and rolling stock costs and it's $6-8B, which is about in line (including inflation adjustment) with what the FTA was scoring the project as prior to Baker putting two hands around the project's neck. It's nowhere near ESA-level bad...nothing else in the whole world is ESA-level bad.

I am aware of the political climate this study was done under, but ultimately this is the best estimate we have for costs so let's try and get an absolute minimum number based on the basic 2-track CA alignment. Here is the provided tunneling costs (IE: No rolling stock) table from the 2018 study:

Let's start off by just subtracting allowances, electrification, and layovers cost, this brings the total for the 2-track, 2 station design down to $7.598 billion. Multiply the stations cost by 1.5 for 3 stations and the cost is now $8.3 billion. I would consider this the absolute minimum cost for the full build, (4 tracks, 3 stations, all lines.) I know this study is not perfect, but to just call their cost estimates entirely fraudulent without any evidence is just reckless.

 

[F-Line to Dudley]

I am aware of the political climate this study was done under, but ultimately this is the best estimate we have for costs so let's try and get an absolute minimum number based on the basic 2-track CA alignment. Here is the provided tunneling costs (IE: No rolling stock) table from the 2018 study:
View attachment 50252
Let's start off by just subtracting allowances, electrification, and layovers cost, this brings the total for the 2-track, 2 station design down to $7.598 billion. Multiply the stations cost by 1.5 for 3 stations and the cost is now $8.3 billion. I would consider this the absolute minimum cost for the full build, (4 tracks, 3 stations, all lines.) I know this study is not perfect, but to just call their cost estimates entirely fraudulent without any evidence is just reckless.

Their own numbers don't even agree with their own numbers. From the January 2019 report. . .

How do you lose three-quarters of the tunneling works cost in one year if not for some funny, funny math???


EDIT: @Riverside delved into some of the extreme oddities on the 2019 cost breakdown in this post, especially zeroing in on how similar the portal/lead and station costs are on all the Alts. despite the 4-track CA/T being the only one in the bunch to include an Old Colony/Fairmount portal or a Central Station. It's all darts thrown wildly at a wall.

 

[TheRatmeister]

How do you lose three-quarters of the tunneling works cost in one year if not for some funny, funny math???

The "Total Project Costs" line matches up almost exactly with the 2018 study, so presumably by using that number and condensing contractors costs and tunneling risk down into that category. Even if we only want direct costs, no contingencies or escalation, we're still at $8 billion for the full build.

 

[F-Line to Dudley]

The "Total Project Costs" line matches up almost exactly with the 2018 study, so presumably by using that number and condensing contractors costs and tunneling risk down into that category.

So why are all the itemizations a such a bunch of gobbledygook compared between the Alts.? Portals and stations don't scale remotely rationally to the "doubling" you claim, and the report doesn't even make an attempt to explain why. The only items that do a true double are the associated soft costs, not the direct construction costs. That's deeply, deeply weird and deeply, deeply suspect.

 

[BosMaineiac]

The north and south entrances to the tunnel are too steep. But I think everything in between (basically Summer Street to North Washington) is under 3%, which is what the FRA was allowing in other NSRL plans. If @Hooledeli 's plan is to tap into the tunnels just north of South Station, the grades are fine until a bit past Haymarket. (What happens then, I don't know what they have in mind)

One issue I see past haymarket is the pinch between state st and the blue line tunnel roof. I’m not sure if the grade exceeds 3% but it’s pretty darn close. There’s also the vertical curve right at the pinch which could cause issues for trains.

I don't think this is right. The ceiling you see in the tunnels are just panels covering a massive open space for ventilation. It could be possible to raise or remove the panels to accommodate a train. More details here, if you're interested.

I believe the photo in the linked post is of the Ted at one of the portals, which definitely has a large height clearance for trucks.

The CA/T, at least at the portals, has nothing between the girders and tunnel ceiling, as evidenced by past strikes by rigs:

Edit: I believe there are ceiling panels at other portions of the tunnel, but I don’t think there’s quite as much space as you say.

Yeah, I keep wondering about that. Is there some study where they definitively say it's no longer possible to tunnel under South Station? The foundation for the new tower is all east of tracks 1-4, so I've wondered if it would be possible to tunnel just under those tracks (but I also have no idea what the foundation for the bus terminal looks like). Basically, there's this diagram from a NSRL proposal back from the Big Dig days, with 4 tracks directly under South Station. That can't be done anymore, but I wonder if the western two tracks are still possible.
View attachment 50250

Well the overbuild does span the entire width of the platforms, so I imagine the deep foundations extend the entire width as well. There’s also a major difference between building the stations before building the foundations and going back and beefing them up as part of the underground train shed later.

 

[TheRatmeister]

So why are all the itemizations a such a bunch of gobbledygook compared between the Alts.? Portals and stations don't scale remotely rationally to the "doubling" you claim, and the report doesn't even make an attempt to explain why. The only items that do a true double are the associated soft costs, not the direct construction costs. That's deeply, deeply weird and deeply, deeply suspect.

To suggest an above board reason, it could be that there's a lot more different with the 4 track alt than just "2 bores, scale everything up." Stations could be at different locations, the tunnel depth could be different, or any number of other things could be changed either slightly or significantly, for a potential number of reasons just as high. Of course ultimately this is just a guess, neither I nor anyone else here knows the real answer. What we can definitely say is that this study and report is far from perfect, and this does need to be revisited, but I don't think we should expect miracles of cost-cutting from a 2nd study. At the end of the day building anywhere from 2-6 20ft by 700ft platforms and the rest of the associated stations 120+ft below a major city is just a difficult and expensive thing to do. At some point we will need to consider what are the benefits of electrification, and what further benefits would NSRL bring, and what are the costs of just electrification, and just NSRL assuming electrification of the system.

 

[F-Line to Dudley]

To suggest an above board reason, it could be that there's a lot more different with the 4 track alt than just "2 bores, scale everything up." Stations could be at different locations, the tunnel depth could be different, or any number of other things could be changed either slightly or significantly, for a potential number of reasons just as high.

It's not "a lot more different". The 2019 Feasibility Reassessment spelled out the differences or lackthereof. It's twin-bore on the same alignment, and "the new underground South and North Stations are constructed in the same manner as for the Central Artery Two-Track alternative". So if NS/SS aren't going to be different, is Central Station really costing us more than both of the all-important terminals put together?

Of course ultimately this is just a guess, neither I nor anyone else here knows the real answer. What we can definitely say is that this study and report is far from perfect, and this does need to be revisited, but I don't think we should expect miracles of cost-cutting from a 2nd study. At the end of the day building anywhere from 2-6 20ft by 700ft platforms and the rest of the associated stations 120+ft below a major city is just a difficult and expensive thing to do.

We did indeed get "miracles of cost-cutting" from the Red-Blue do-over after Baker/Pollack got called out on the blatancy of the original sandbag. And East-West has been shedding cost and increasing ridership in a furious backpedal ever since holes got poked in its sandbagged findings (to say nothing of the competing Patrick Admin. NNEIRI study's cosmically lower costs and better cost-benefit). And Alon Levy, high priest of transit costs, thinks there's ample wiggle room for savings in NSRL's station bores given the type of construction. There's a well-established pattern of bullshitting going on with that Administration's studies of signature transit expansion projects. When numbers appear to be this crooked, given the history involved and the lack of credible explanations to the contrary I think we're well within our rights to be skeptical of their overall credibility.

At some point we will need to consider what are the benefits of electrification, and what further benefits would NSRL bring, and what are the costs of just electrification, and just NSRL assuming electrification of the system.

Yes. NSRL's mission statement is completely incoherent if it isn't predicated on pre-existing Regional Rail. "One mile gap. . ." and "Fitchburg!...to Greenbush!" sloganeering from the Dukakis/Weld/Salvucci advocacy contingent says nothing about what the project would do for the region, because nowhere in it is the word "frequencies" spoken. It's just blanket-assuming barely useful current ops, which isn't going to transform anything about our region's car dependence. This is why TransitMatters is so strident about de-coupling RER from NSRL. NSRL is this wholly abstract concept with hard-to-decipher benefits if you don't have a pre-existing system set up for :30 frequencies out to I-495 and the Gateway Cities and :15 SUAW frequencies out to Route 128, at thresholds where car dependency is going to change and connecting bus usage in the suburbs is going to change and end-to-end vs. intermediate-to-intermediate trip distribution is going to change. So there absolutely are prerequisites before we can reliably get the Vision Thing in order on what NSRL does. But implement Regional Rail fully enough, and the benefits of NSRL will be readily evident by what new and useful trips can be unlocked by reaching across that barrier. I fully believe that build sequence--RER first and fully--leads to a cresting wave of advocacy for NSRL. So it behooves us to leave a somewhat clean blueprint behind for when we get there, not endlessly muddied waters and the wreckage of malicious-intent past studies.

 

[Hooledeli]

omg i didnt think i would generate this many responses ty everyone

my (current) plan is to make the NSRL start going deeper somewhere after central station, then go underneath the rapid transit of north station, under the river and then come back up on the other side. im not sure if the portals could be closer? so yeah

alternatively, if the government center parking garage takes long enough to get finished or just falls through (might already be done i havent been to gov. center in a while) then haymarket could be rebuilt to allow space for the tracks to go under canal street and then link straight into north station (i *kinda* like this idea but i really dont see much benefeit)

i dont really have a source for if theres room above the silver line tunnel, i just kinda assumed because theres the councorse there, also there seems to be more room above the red and silver line tunnels then they need

frankly my initial idea was to just tear up and rebuild the central artery again but if the highway tunnels could really be utilized then thats awesome (a whole would still need to be made to take out the TBM from the north station portals)

the underground north station that this would be produce would be shallow enough that the portal would be like somewhere in the wide rail trunk right before north station instead of 3 seperate portals

also the thing i said bout connecting directly into north station is stupid, theres literally no room under canal street and it would be worse then an underground one anyway because the current transfer to rapid transit is very annoying

also idk what i was going on about with the gov. center project getting halted (i do want to rebuild haymarket anyway but thats a different story)

as for tunneling directly under south station, im not sure about the tower's foundations but im pretty sure lowering 4 tracks by 20-25 feet wouldnt interfere, and for the south station buildings original old foundations im not sure whats there but a steel arch being pushed forward inch by inch would create the neccesary gap (this is how they dig through old building's foundations in europe and stuff)

sorry for all my yapping and ty for considering my suggestion seriously

 

[Riverside]

And Alon Levy, high priest of transit costs, thinks there's ample wiggle room for savings in NSRL's station bores given the type of construction.

This was an interesting piece, thanks for linking (and for the shoutouts). Alon's suggestion that 4 tracks could be accommodated via a single-but-enlarged bore is an interesting one, which would definitely impact my opinion of the project. What are the considerations for that kind of design decision?

 

[Charlie_mta]

This was an interesting piece, thanks for linking (and for the shoutouts). Alon's suggestion that 4 tracks could be accommodated via a single-but-enlarged bore is an interesting one, which would definitely impact my opinion of the project. What are the considerations for that kind of design decision?

The recent SR 99 deep bore tunnel under downtown Seattle carries 4 lanes of highway, 2 lanes on each level. See images below. So, based on that I would assume 4 tracks is possible in a single deep bored tunnel.

 

[TheRatmeister]

The recent SR 99 deep bore tunnel under downtown Seattle carries 4 lanes of highway, 2 lanes on each level. See images below. So, based on that I would assume 4 tracks is possible in a single deep bored tunnel.

The 2018 study proposed building the platforms within the bore. (And for good reason, when you're this deep it makes construction of the stations significantly easier.) You'd need a bore even bigger than the Seattle one to make that work, I'm not sure if that's possible/feasible.

 

[Longfellow]

Weird question — the north station incline to science park is actually four tracks wide towards the bottom. There’s two tracks that appear to dip under but just end at a wall. Are those storage tracks or are they actually a provision for service points east?

 

[Riverside]

Weird question — the north station incline to science park is actually four tracks wide towards the bottom. There’s two tracks that appear to dip under but just end at a wall. Are those storage tracks or are they actually a provision for service points east?

They definitely are storage tracks, at least. Whether they are provisions for some sort of extension is, IIRC, somewhat of an open question and usually the topic of speculation. For my part, I’m not sure where such an extension would even go, but stranger things have happened for sure.

 

[Longfellow]

They definitely are storage tracks, at least. Whether they are provisions for some sort of extension is, IIRC, somewhat of an open question and usually the topic of speculation. For my part, I’m not sure where such an extension would even go, but stranger things have happened for sure.

Good to know, I see people foaming over a Tobin bridge extension occasionally and that gets me excited too about the idea. But there’s probably much more sensible ways to do that lol

 

[Riverside]

Good to know, I see people foaming over a Tobin bridge extension occasionally and that gets me excited too about the idea. But there’s probably much more sensible ways to do that lol

IMO, the storage tracks are pointing the wrong way — toward the West End, rather than toward Charlestown. I love a good Tobin Bridge crayon map myself, but I figure we’d first try to hook in to the 90 degree turn just north of the North Station platforms.