MARC and the new B&P / Frederick Douglass Tunnel

srepetsk
Are there any photos or news stories of the day linking these two together? I'd love to know more!

None that I know of. I learned that it was previously used by one of the subcontractor when it was boring the first of the two tunnels (outbound) between Rock Creek and Yuma Street.

WMATA has a picture of the head of the boring machine in their photo collection but as far as I know it has not been published on the Internet. I got the opportunity to see the head of the boring machine after it punched through the inbound tunnel at the base of the Van Ness station north vent shaft. That picture is was nothing compared seeing in person.

west point
The red line bores probably are much smaller diameter than the needed bore size for Amtrak and MARC. Will need a much stronger TBM and larger to handle the concrete liners which will have different radius of curves.

EDIT: Forgot of freight plate "H" clearances.

The tunnel boring machine was 21'. The lining is 1' thick poured in place concrete resulting in a 19' inside diameter. Most of the other bored tunnels with poured in place concrete linings have an inside diameter of 18'.

To get Plate H clearance the boring machine will likely be 30' resulting in a 28' inside diameter using precast concrete segments for the lining.

I am curious about how the electrical systems for the catenary will be adjusted for the creation of the new tunnels and the retirement/refurbishment of the existing tunnels:

- Will there be new 138kV circuits run through the new tunnels?
- Will the existing 138kV circuits in the existing tunnels be removed completely during retirement/refurbishment or retained?
- Will the substations at Loudon Park, Baltimore and North Point be significantly adjusted to support any new 138kV circuits, as well as the new 12kV feeders and additional catenary at the new interlockings and in the new tunnels?
- Will all of the catenary poles between Loudon Park and the south portal, and North Point and the north portals of the Union Tunnels, need to be replaced to support any additional 138kV lines that might be added?

I am interested to see where and how Amtrak and their contractors plan out the phasing and scheduling of these works to avoid disrupting the Acela, Regional and MARC services through Baltimore. Are all of the interlockings still fed solely from the 6.9kV signal power lines or are they dual-fed from a 60Hz supply too? How much appetite for risk is there if the electricians can't return control to the power directors and services have to remain suspended?

Have read the project docs fairly much. As of now cannot answer the questions. Partly because it has been too long since observing the layout.
Speculations.
1. If the 138 kV foes above ground between preent portals then only a few relocations of the 137 support poles will be needed to mitigate the slight east and west relocations of the main that are planned. Otherwise???
2..There will probably be dual isolated 12 kV feeders in the new bores. Probably the ones in the old tunnel will be replaced once new bores in service. They willl become backup until the old bores are condemmed. Old bores might be used for MARC storage in one proposal.

Last I saw, the old bores were to remain for the freight service.
If say, the Claremont branch were rebuilt, and csx (or someone else) were granted freight rights, they'd not be needed at all.
If one were able to rebuild the tunnels, without trying to maintain service, would it be cheaper than the current work?
It would be a shame to give up potential connections to the subway and light rail, for marc service.

I'm assuming you are thinking both tunnels, the FD and the B&P. Have MARC/Amtrak take the FD while the B&P is rebuilt.

The benefits are minimal. You'll still get a 30 MPH limit (compare with 70-100 mph on the FD). You'll have to rebuild a spur line between CSX's Hanover Subdivision to that part of the NEC. You'll still have plans to put in two more bores to shuffle MARC trains to station tracks 2/3/4/5, and maybe a full interlock before then.

What I can see, if the B&P is rebuilt, is a small storage yard for MARC trains and tie-ins near West Baltimore MARC and the CHARLES interlocking. Yes, you could run trains through the B&P... if you like them slow. I can see it as a staging tunnel that'll let Amtrak keep the FD clear for actual travel (unlike having to send a train through the East River tunnel from NYP to get to Sunnyside and clog up a slot that a Boston-bound train could use).

This pretty much sums up reuse.For potential regional rail use.

Https://baltimoreinnerspace.blogspot.co ... upton.html
The was a plan for , riverside is getting rebuilt to be a staging yard, so maybe we missed the Mta started rebuilding Claremont branch?
SOmehow, they are doing something right that would give operational flexibility?
Building a connection between ns and csx at Bayview would be possible.

I would suspect that no matter how much rebuilding of the B&P tunnels that there will always be need for major work from time to time. Still have an alternate is very worthy in case of an accident that closes one bore of the FD. With one bore of FD closed the other bore cannot be used for reenue service ( NFPA 130 ).

Correct me but isn't the B&P tunnel actually 3 separate tunnels separated by short open air sections?

True. I don't know how the 3 sections are designated for M/W purposes, etc., but when I worked in Ballamer the whole thing was referred to simply as the B&P Tunnel.

west point wrote: ↑Sat Jul 09, 2022 8:20 pm I would suspect that no matter how much rebuilding of the B&P tunnels that there will always be need for major work from time to time. Still have an alternate is very worthy in case of an accident that closes one bore of the FD. With one bore of FD closed the other bore cannot be used for reenue service ( NFPA 130 ).

Correct me but isn't the B&P tunnel actually 3 separate tunnels separated by short open air sections?

http://www.trainweb.org/oldmainline/bnp1.htm#top
Yes, one of the tunnels was partly daylight.

west point wrote: ↑Sat Jul 09, 2022 8:20 pm I would suspect that no matter how much rebuilding of the B&P tunnels that there will always be need for major work from time to time. Still have an alternate is very worthy in case of an accident that closes one bore of the FD. With one bore of FD closed the other bore cannot be used for reenue service ( NFPA 130 ).

Correct me but isn't the B&P tunnel actually 3 separate tunnels separated by short open air sections?

From my understanding, they were all one, but two sections collapsed and they made those areas open-air.

scratchyX1 wrote: ↑Sat Jul 09, 2022 5:11 pm This pretty much sums up reuse.For potential regional rail use.

Https://baltimoreinnerspace.blogspot.co ... upton.html
The was a plan for , riverside is getting rebuilt to be a staging yard, so maybe we missed the Mta started rebuilding Claremont branch?
SOmehow, they are doing something right that would give operational flexibility?
Building a connection between ns and csx at Bayview would be possible.

TBH I could see the Upton connection, because my office is right next to the Charles Center subway station. I can't see the others because they're too short between stops.

However, I think the 30 MPH speed limit is a deal-breaker, when the FD is 70-100 MPH... and the future threat of four bores over two adds more nails to the B&P's coffin. It saves time both inside and outside of the tunnels as you can speed up past 30 before slowing down for West Baltimore MARC... or you can blow past at track limit outside because you matched it earlier.

Any rebuild of the B&P is going to be of limited utility, ether freight or staging of MARC trains... and I'm not sure it's even tall enough for a Superliner.