Jump to content
afigg

Baltimore B&P tunnel replacement study

Recommended Posts

Portal Bridge will be first to go (fail) is my prediction...

It's the cheapest one to fix, only about a Billion, so it should get done first. As soon as Congress thinks it is important.

Share this post


Link to post
Share on other sites

Actually the Sawtooth Bridge will probably fail,before the Portal Bridge, considering the amount of toothpicks and baling wires that are already used to keep it from falling over. :)

Share this post


Link to post
Share on other sites

Actually the Sawtooth Bridge will probably fail,before the Portal Bridge, considering the amount of toothpicks and baling wires that are already used to keep it from falling over. :)

Is the replacement ready? iiuc For the new Portal Bridge, the Environmental studies are done and the construction plans are ready. All it needs to go is a Billion spread over a couple of years.

 

But I'm OK with a new Sawtooth Bridge, for less than a Billion, right?

 

The new Baltimore tunnel, the new Hudson tunnel, and a new Susquehanna bridge are nowhere near ready with environmental studies, construction plans, or the multi Billions needed. But in a sane world (a parallel universe, so to speak), Congress could easily find money to do a bunch of small < Billion projects while preparations continue on the multi-Billion biggies.

 

It's really discouraging that the fast section in New Jersey is running late and over budget (another thread). Makes it harder to convince Congress to start spending on the NEC's line-up of smaller projects.

Share this post


Link to post
Share on other sites

AFAICT the current plan for the Sawtooth Bridge is to keep patching it within what can be hidden in the regular maintenance budget until one of two things happens:

 

1. It just falls down (hopefully not taking a train with it) - and then it can be fixed using whatever emergency funding may become available or not.

2. Money is found for the quadruple tracking between CP Swift and CP Dock, which will include complete redoing of that entire segment anyway.

Share this post


Link to post
Share on other sites

There was a local community association meeting presentation on September 1, 2015 with a new lengthy set of viewgraphs (52 pages total) with renderings of the alternative routes and locations for the tunnel entrance and exit complexes. The file links are currently on the front page of the B&P Tunnel study website.

 

The presentation is split into 2 PDF files, both fairly large at 5 to 6 MB. Here are direct links: Part 1 w Slides 1 to 30 and Part 2 w slides 31 to 52. The renderings of the alternative tunnel entrances with 4 tracks and 4 tunnels show that some of them will require taking of a fair amount of property and land in west Baltimore. One of the alternatives is a complete rebuild in place of the existing B&P tunnel with a cut and cover digout of the B&P tunnel along its entire length to increase vertical clearance by 5'. But that would be extremely disruptive to operations, if not requiring the southern end of the NEC to shut down for extended periods.

 

So, anyone want to figure out which alternative is going to be selected? which may not be the one you would pick.

Share this post


Link to post
Share on other sites

This poster's choice would be 3C 1st then 3 A. Reasons.

 

Those routes seem to allow for the gentlest curves allowing for the fastest train speeds in and out of Baltimore station. It would allow for the fastest speeds also at west Baltimore station. Another good point would be that new crossovers at the west end of the station are constructed for higher speeds.

If the crossovers are able to be placed far enough west then that gives space for the platforms to be lengthened to the 1200 feet listed in the FRA NEC preliminary EIS. East side platform length increases might require another Lincoln tunnel.

Share this post


Link to post
Share on other sites

There were a round of public hearings in October to present the results of the Alternative analysis for the tunnel replacement. The Final Alternative Analysis report has been posted to the website here. The 111 page report is broken into 2 files, but it is one report. With a lot of renderings, diagrams, and data on the Alternatives. The public comments section is at the end of the report if you want to read what the public reaction is.

 

This a significant step because now that they down selected the Alternatives to Alternative 3 Options A, B, and C. Alternative 11 has been dropped. Hopefully they have or can get enough funding to carry this study through the EIS process.

Share this post


Link to post
Share on other sites

Interesting. So the B&P tunnels were fundamentally defective in design when they were originally built. Yeech. They were "just built really, really badly".

 

There are a lot of tunnels which are a lot older which are in perfectly good condition. Clearly a bad design.

 

It's interesting to learn that most of the "tunnels" are not rock tunnels, but cut and cover. The classic way to fix those is, um, to take the cover off and put a new cover on. It's been done. It works. It's not even that expensive.

 

I suppose it's considered to be too disruptive; since the tunnels are considered to be on a bad route anyway, I guess they figure improve the route while they're at it..

 

It's a little weird that they were built with such a bad design. There are older hard rock tunnels in good condition; there are older cut-and-cover tunnels in good condition. Deep bore (not cut and cover) earth tunnels were avoided whenever possible until the 1990s, after the trouble with Brunel's tunnel under the Thames -- but even Brunel's tunnel is still functioning just fine. Who built the B&P tunnel? If it's really as bad off as people are saying, the original builders were clearly incompetent.

 

Maybe they just had better engineers in the UK than in the US in 1873.

Edited by neroden

Share this post


Link to post
Share on other sites

To be fair though Brunel's tunnel in East London has been completely rebuilt in the last two decades, eventually making it a part of the London Overground route which runs through it now. One critical difference between it and the B&P Tunnel though is that the East London Tunnel is a shield bored tunnel with brick and mortar lining designed specifically to operate under water - indeed the shield technique was invented for building this tunnel, whereas the B&P tunnel is a cut and cover tunnel basically running under various streets, and ancient leaky water supply and sewage conduits.

 

OTOH Severn Tunnel stands as testimony to excellence of British engineering. It will finally get some additional TLC as part of the electrification of the route to Wales through it. And even that tunnel has serious leakage issues, but none that threatens the integrity of the tunnel. It does throw an additional challenge to installing catenary in it. More likely the technology used will be shielded beams instead of catenary to keep it protected from seeping water.

 

I wonder why you say deep bore tunnels were avoided until the 1990s. Are you referring to the inherent higher cost of building deep bore tunnels perhaps? AFAIR almost all of London's tube system, which is deep bore tubes in clay, was built way before 1990. Actually in London, they seemed to prefer going deep bore over cut and cover, once they perfected the technique for building those. And even more oddly, most of the deep bore tubes follow the alignment of major thoroughfares above.

Edited by jis

Share this post


Link to post
Share on other sites

Isn't there a plan to have one of the four tubes cross under another tube? If so, why would this be the case?

In the B&P tunnel replacement? Not that I am aware of. What four tubes?

Edited by jis

Share this post


Link to post
Share on other sites

Are there any updated cost estimates for each option buried somewhere in the Alternative Analysis Report (or found elsewhere)? I've skimmed the document, but didn't see any.

Share this post


Link to post
Share on other sites

 

Isn't there a plan to have one of the four tubes cross under another tube? If so, why would this be the case?

In the B&P tunnel replacement? Not that I am aware of. What four tubes?

Alternatives 3 and 11 have 4 bored single track tunnels. They dropped the concept of a larger diameter bored tunnel for 2 tracks because of constraints of the proposed route and depth profile. And, yes, the diagrams in the Alternative report show one tunnel ducking under the others in the various options.

 

Quoting from the executive summary in the report:

 

Alternative 3 and Alternative 11 would replace the B&P Tunnel in a new location. Consideration of a double track tunnel was eliminated from both alternatives because of its much larger tunnel diameter (about 50 percent larger compared to a single‐track tunnel), the tight profile constraints posed by the design criteria, portal elevations, and intermediate underground obstructions. The resulting configuration is using four single‐track tunnels for all alignment options for Alternatives 3 and 11. Horizontal excavation (boring) is proposed for these alternatives to minimize surface impacts. Four tracks in four separate bores of equal size would support train capacity requirements, service flexibility for conflict‐free operations, design within physical constraints, and constructability. The tunnel vertical clearances for both Alternative 3 and Alternative 11 would also accommodate double stack container freight.

 

Alternative 3 and Alternative 11 each incorporate a subterranean grade‐separated track crossing or “duck under” approach to aligning the four individual tunnel bores to minimize conflicts between turning trains and increase operational efficiency, while correctly aligning tracks with those being planned at Penn Station. Each option includes ventilation plants at permanent portals and at an intermediate location along the tunnel, and emergency egresses. Outside approaches to portals for each would consist of open trench transitioning to cut‐and‐cover to the portal entrance. Each provides universal interlocking to the NEC mainline and avoids the Metro Subway tunnel while servicing the West Baltimore MARC Station. All of these options would relocate a pier of the CSX Baltimore & Ohio Bridge in Jones Falls Valley. All Alternative 3 and Alternative 11 options also consider disposition of the existing tunnel.

 

The price tag of the B&P tunnel replacement is going up with the decision to expand the scope of the project to 4 new tracks in 4 bored tunnels. The price range for Alternative 3 Options A, B, C is from $3.7 billion to $4.2 billion. Alt 3 Option A has the smallest impact on the taking of property and land and the least expensive at $3.7 billion at the tradeoff of less in travel time savings for the Acela, Regionals, and MARC.

Share this post


Link to post
Share on other sites

Are there any updated cost estimates for each option buried somewhere in the Alternative Analysis Report (or found elsewhere)? I've skimmed the document, but didn't see any.

Yes, on page 72 in the Evaluation table comparing the Alternatives and Options on pages 71 to 75. The table shows the projected impact on the community in displaced businesses, residences, and amount of land taken on page 74. There are political considerations here, even for West Baltimore, so Alternative 3 Options B taking 48 residential buildings (that is buildings, not # of residences), 10 businesses, 6 community facilities is going to run into a lot of resistance if that is selected. Which is why the Option chosen is likely to be Alternative 3 Option A or C.

Share this post


Link to post
Share on other sites

Ah, I need to catch up with the latest I guess. If we could somehow get their website to run at anything like reasonable speed for downloading those enormous files that would be nice :)

Edited by jis

Share this post


Link to post
Share on other sites

So I see that in all new build alternatives they are crossing the west/southbound slow track (track 4) over from the the south middle position (between tracks 1 and 2) to the northmost position (normal track 4 position) via a duck under. That is a very good idea since it eliminates a significant conflict between west/south bound MARC trains and all Amtrak trains.

 

Basically 1,2,3,4 coming in from Washington gets flipped to 1,4,2,3 at the station, 1 being closest to the station head house.

Edited by jis

Share this post


Link to post
Share on other sites
I wonder why you say deep bore tunnels were avoided until the 1990s.

 

I'm strictly referring to deep bores in "bad soil". In London, they were happy to bore through the solid clays and rocks north of the river, but they assiduously avoided the mud south of the river until pressure-balance TBMs were developed.

Share this post


Link to post
Share on other sites

Hmm. The diveunder sounds like a good arrangement... seems like all trains going north of Baltimore Penn will have to be on the express tracks south of Baltimore Penn, however.

Share this post


Link to post
Share on other sites

Express tracks will often be used but close examination of the west end of the station shows puzzle switches installed. Express will speed up trains that do not have to change tracks to / from BAL station. Other trains will have to slow to transverse the interlocking. This appears to mirror the practice of new tracks in Europe that allows MAS as soon as dispatched from station and higher speeds to the station. Don't stand too close to the west end of the BAL platforms while trains moving faster.

Share this post


Link to post
Share on other sites

The Draft EIS was issued last week (week of 14 Dec 2015).

 

Relevant diagrams are easily found here (PDF).

Interesting. Alternatives 3B, at a capital cost of $4 Billion, would gain 2 1/2 minutes of trip time savings, similar to Alternative 3C at $4.2 Billion, while Alternative 3A at $3.7 Billion, would save a shade less than 2 minutes.

 

But Alt 3B would take 150 on-street parking spaces, while Alt 3A would take none at all, and Alt 3C only 40. That's probably the deciding factor right there. I mean, what's more important, saving 30 seconds for ~6 million riders today and many more in the future, or MY (taxpayer-subsidized free) PARKING PLACE!

Share this post


Link to post
Share on other sites

The tunnel replacement study has advanced to settling on a revised Alternative 3B route.

First, there is new material and updates to the design alternatives that will be presented at April public meetings. Alternative 3C has been eliminated. Both 3A and 3B have undergone revisions with 3B undergoing a lot of changes to reduce the impact on property taking with a shifted route for the tunnels.

Slide comparing 3A and 3B original vs revised with the property impact and projected trip time reductions.

Even before the second April public meeting, the FRA has issued a news release that the project team has decided on revised Alternative B. Which I find somewhat odd as typically the final alternative is not publicly selected until the study process has tediously ground through all the public meetings and getting comments from umpteen rounds of meetings. US DOT/FRA press release: FRA Releases Revised Proposal to Rebuild B&P Tunnel After Receiving Input From Baltimore Community. Excerpt:

WASHINGTON – The Federal Railroad Administration (FRA) today presented a revised proposal to replace the Civil War-era Baltimore and Potomac (B&P) Tunnel based on feedback provided to the FRA by Baltimore residents during three public hearings in February. In December 2015, the FRA presented three options for replacing the tunnel in a Draft Environmental Impact Statement (EIS). Based on feedback during three recent meetings in February and 19 public hearings, open houses, project and community association meetings during the last two years, two options have fallen (Alternative 3A and Alternative 3C) from consideration, and FRA will make several significant changes to Alternative 3B in the Final EIS.
....
The FRA will continue to work with the public over the next several months to mitigate the effects of the project. The Final EIS, scheduled to be published later this year, will include this coordination and the resulting mitigation plans and environmental commitments.

Since the FRA is the lead on the EIS, one would venture that the FRA can fast track the official Record Of Decision. So if there is a ROD in early to mid-2017, where does the $4 billion come from the build the new Baltimore tunnels?

Share this post


Link to post
Share on other sites

Create an account or sign in to comment

You need to be a member in order to leave a comment

Create an account

Sign up for a new account in our community. It's easy!

Register a new account

Sign in

Already have an account? Sign in here.

Sign In Now

  • Recently Browsing   0 members

    No registered users viewing this page.

×