Friday, September 2, 2011


Second Avenue Tunnel Boring Machine (TBM)
Nears the End of its Second Run

Breakthrough into Existing Lexington Avenue/
63rd Street Station Just Weeks Away

Recently released data indicates that the TBM working under Second Avenue is now about 500 feet away from its final stop, the Lexington Avenue/63rd Street station.

Based on its current rate of progress, it could be estimated that it will hole through into this station on or about Friday, September 16th.

The TBM, known to the sandhogs as the worm, started its second run (the east tunnel) at a point just south of 92nd Street back in March of this year. Since then it had mined a total of 7,221 linear feet, as of August 31st.

The 485-ton, 450-foot-long machine is now in the process of making a relatively tight westerly curve as it grinds its way towards a stub cavern at the Lexington Avenue/63rd Street station. The stub cavern, shown in the diagram further along in this posting, was built in the late 1970s when this station was original constructed.

The TBM previously mined 7,162 feet of the west tunnel under Second Avenue.

Phase I of the Second Avenue subway (i.e. the extension of Q Line service to the Upper East side) is currently scheduled to be completed in December 2016.

Partial Diagram of Phase I of the Second Avenue Subway
Google Maps
(left-click on the image above for a closer look)
-- The approximate location of the TBM, as of 8/31/11,
is designated with a red cross on the map above.

G3/G4 Tunnels and 72nd Street Station
Second Avenue Subway
(left-click on the image above for a closer look)

This diagram details the current and planned subway tunnels just to the east of the Lexington Avenue/63rd Street station.

The G3 & G4 tunnels (shown above) are being built as part of Phase I of the project. The tunnels designated as S1 & S2, for the future "T Line", will be built during Phase III of the project.


Last Reported Location
of the Tunnel Boring Machine
btw. 64th & 65th streets
as of 8/31/11

TBM Run No. 2 (east tunnel)
Tunnel length: 7,789 linear feet (LF)
Start: just south of 92nd Street
End: Lexington Av / 63rd St Station
7,221 LF mined as of 8/31/11
568 LF to run

August TBM Mining Data:
Distance mined: 1,265 linear feet (LF)
TBM mining days: 23
Avg. distance per day: 55 LF


Here's a listing of the recent additions
to the right-hand column of The Launch Box

"No Subway, but a Little Silence on Second Avenue"
By Michael M. Grynbaum
The New York Times - 8/15/11

"No more underground blasts at night on 2nd Ave" (2:00)
By Jeff Pegues
WABC-TV - 8/15/11

"MTA behind schedule, over budget on two mega projects, feds say"
By Marc Beja
amNew York - 8/22/11

Feds: East Side Access, SAS won’t open until 2018 - 8/22/11
By Benjamin Kabak
2nd. Ave. Sagas - 8/22/11

"Underground Economy: Cashing in on Rubble From the 2nd Avenue Subway" (4:08)
By Ilya Marritz
WNYC - 8/23/11

"A Bonus for First Avenue: It's Not Second"
By Laura Kusisto
The Wall Street Journal - 9/2/11


A Footnote:

After four years I've decided that its time to change the layout of this blog. The layout (known as a template) that I selected when I started in 2007 is so old its not even available on the current web site today!

I plan to adjust the new template over the next week as I play with all of the new options. In the meantime, please stand by while I rejig the blog a bit.



Anonymous said...

Any idea how far along is the other, shorter curve from the west tunnel into 63rd st station? I understand it was to be minded by hand.

The Launch Box said...

An earlier notice from the MTA said that they started work on the extension of the west tunnel, from 65th & 2nd to the "stub cavern" at the 63rd St/Lex station in mid-June. (the stub cavern is near 63rd & 3rd, so they "only" have about 700 feet to mine.)

This same notice said that the work, to blast this tunnel using traditional techniques, would take about 3 months time.

So, if they've on-schedule, they should be just about finished with this work.

That's all I know at the moment. Maybe some other reader has more up-to-date information that they can share.


Anonymous said...

If you look at that last model the part labeled G3/S1 Cavern II is mined and the section marked G3/S1 Cavern I has just been started.

This is what happens when the MTA sets the vibration limit at an unreasonably low level. Sorry I don't know the reason behind it.

Everything else seems to be going good though. Don't wanna say too much but it's a lot easier to build a station @ 34th & 11th than 72nd & 2nd. I guess that's the difference between an industrial district and a residential district.