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  • Discussion related to DC area passenger rail services from Northern Virginia to Baltimore, MD. Includes Light Rail and Baltimore Subway.
Discussion related to DC area passenger rail services from Northern Virginia to Baltimore, MD. Includes Light Rail and Baltimore Subway.

Moderators: mtuandrew, therock, Robert Paniagua

 #208090  by octr202
 
Fascinating. Thanks for sharing that.

So are the vaults free-standing then, i.e., like a shell inside the cavern? I always imagined that they were attached/in contact with whatever the material was the station was tunneled out of, but that sight of people on top of it makes me wonder...

 #208281  by Sand Box John
 
Quote "octr202"
Fascinating. Thanks for sharing that.

So are the vaults free-standing then, i.e., like a shell inside the cavern? I always imagined that they were attached/in contact with whatever the material was the station was tunneled out of, but that sight of people on top of it makes me wonder...


This is the only 22 coffer station built this way, precast concrete segments assembled in a cavern excavated out of the bedrock. The reminder of the 22 and 6 coffer stations are all cut and cover poured in place concrete. With the exception of Rosslyn. Rosslyn is free standing poured in place concrete arch vault in a cavern excavated out of the bedrock. All of the 4 coffer stations north of Dupont Circle were built in a similar manner to the what is seen in the image. Forest Glen and Wheaton are single track versions of the stations north of Dupont Circle. The section of the lower level Green line E Route platform in subway at Fort Totten was built in a similar manner to the way Forest Glen and Wheaton were built.

Columbia Heights is a hybrid version of the freestanding precast concrete vault built in a cavern. Unlike the other where the cavern was excavated out of the bedrock, the walls and roof for the cavern were built first and the surface was restored.

The way Columbia Heights was built was slurry walls were excavated the length of the station on both sides. To a depth below the finished station invert slab. The area between the slurry walls was excavated to a depth above the finished vault arch and a steel reinforced concrete arch was poured. The excavation was then back filled and the surface was restored. In the meantime the area under the steel reinforced concrete arch was excavated creating a cavern The invert slab was poured and the precast concrete vault segments were assembled in the cavern.

 #212766  by NHRR WTBY
 
I saw a great shot in the Washington Post a while back...I think it was on the occasion of Metro's 30th anniversary. It was the entrance to the Pentagon City station...sitting all by it's lonesome in the middle of a vacant lot. Things have certainly changed around there since then.

 #212856  by Sand Box John
 
Here is another one http://www.chesapeake.net/~cambronj/wma ... 27-75c.jpg This picture was taken the day after a heavy thunder storm pasted through Washington DC and over ran the banks of the temporary bridge that carried Rock Creek over the A Route Red line tunnel excavation in Rock Creek Park. The water flooded the tunnel to the south and filled the Dupont Circle station with water up to the level of what is now the finished tile on the north mezzanine.

The picture was taken in the passageway at the base of the north surface entrance of the Dupont Circle station on 27 November 1975. That’s me on the right. the picture was taken several months after the previous picture.

 #212866  by Robert Paniagua
 
The picture was taken in the passageway at the base of the north surface entrance of the Dupont Circle station on 27 November 1975. That’s me on the right. the picture was taken several months after the previous picture.

That flood at Dupont Circle caused that station's opening to be delayed 10 1/17/77 from the original inagural 3/27/76 opening.

 #213160  by Sand Box John
 
"Robert Paniagua"
That flood at Dupont Circle caused that station's opening to be delayed 10 1/17/77 from the original inagural 3/27/76 opening.

I don’t think so, Yes it was delayed. However the trackwork and other finish contracts were started later then the contracts for the original segment that opened on 27 March 1976. The rail and rail fasteners were stored in the tunnel north of the station before the station vault, platforms, mezzanines services rooms were built. (I have a picture of track and rail fasteners stored in the tunnel that I took from the fan platform in the S street fan shaft) The third rail was hot and the signal system was up in Farragut north, bumper posts were in place along with a fence beyond the north end of the pocket at N Street to keep people from getting in the area where the third rail was hot at the time of the flood. All of the train control hardware had not been installed in Dupont Circle at the time of the flood. All of the platform level mechanical equipment was damaged along with the switch gear in the newly installed traction power tie breaker station.

The location as to where the surface entrance elevator was going to be placed at Dupont Circle was decided on very late in the process. I don’t recall if the elevator shaft had yet been excavated at the time of the flood. The original location of the surface entrance elevator was to be in a store front of the second building south of the Q Street surface escalator entrance in the 1500 block of Connecticut Avenue. That’s roughly 75’ from where the surface entrance elevator is today.

 #218949  by Robert Paniagua
 
However the trackwork and other finish contracts were started later then the contracts for the original segment that opened on 27 March 1976. The rail and rail fasteners were stored in the tunnel north of the station before the station vault, platforms, mezzanines services rooms were built.

Ok, I see now, so it was more of the contractors' fault then as to why it got postponed.

 #229946  by Sand Box John
 
"Robert Paniagua"
Ok, I see now, so it was more of the contractors' fault then as to why it got postponed.

I don’t think it was totally the contractor fault in this case as WMATA had not made the final decision as to where the surface elevator was going to be very late in the process.

I had always assumed and didn’t recall ever seeing any official opening schedules that included Dupont Circle as being part of the first segment. However I Just remembered this picture I took up in Frostburg Maryland back in October of 2003.

Image

The rest of the roll sign pictures can be seen here.

 #232221  by MACTRAXX
 
Everyone-I have that WMATA tabloid issue and I remember the shot. SBJ-the rollsign photos were interesting-the reason I recall that Metro did away with the rollsigns in the 80s was they were a pain to syncronize thru a train. I also recall one day riding a train that I remember seeing an orange sign saying DULLES AIRPORT - They were really thinking about the future then-any oddball destinations on any rollsigns you have? the blue HUNTINGTON dates them - it was originally going to be the Blue line terminal. MACTRAXX

 #232530  by Sand Box John
 
"MACTRAXX"
Everyone-I have that WMATA tabloid issue and I remember the shot. SBJ-the rollsign photos were interesting-the reason I recall that Metro did away with the rollsigns in the 80s was they were a pain to syncronize thru a train.

To be precise the hardware used to set the signs was very sensitive and would cycle the rolls from end to end until it found the desired sign. Because the signs had 100 positions on them the cycling tended to degrade the stopping marks and or slip stopping marks out of positions as well as damage the mylar. WMATA first solution was to truncate the rolls (remove unused and not yet open stations). As we all know they eventually just dumped them for flip dots

I also recall one day riding a train that I remember seeing an orange sign saying DULLES AIRPORT - They were really thinking about the future then-any oddball destinations on any rollsigns you have? the blue HUNTINGTON dates them - it was originally going to be the Blue line terminal. MACTRAXX

You memory is a little fuzzy, you did see 'Dulles Airport' however it was white text on a black field. The Sign is not mine, though I wish it was. It belongs to a friend of mine in Cumberland Maryland. The sign is truncate and had Dulles Airport removed from it. Dulles Airport was the only destination on the original rolls that was not part of the ARS (Adopted Regional System) I will also note that when WMATA replaced the rolls on the Rohr cars and had electronic signs install on later rolling stock that was procured Dulles Airport was programmed in to the destination sign software, the destination code for Dulles Airport is 34. There were quite a few mid line short turn destinations on the original rolls, some were white text on a black field both inside and out and text on color field outside with strip map inside.