Saturday, January 21, 2012

Secrets Under New York

Many New Yorkers might be surprised to know that the MTA is in the process of building five new stations deep under Manhattan.

These stations are:
  • New stations at Second Avenue & 72nd, 86th, and 96th Streets (for Phase I of the Second Avenue subway.)

Each of these stations is an integral part of the largest expansion of regional transit capacity in the New York metropolitan area in at least a generation.

Underneath Second Avenue, workers are now blasting out the cavern for the new 72nd Street subway station.

All of the photographs that follow were taken inside the 72nd Street station cavern - which is the area outlined in blue on the schematic diagram below.

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


On the floor of the 72nd Street station cavern, looking North.

In the distance, you can see the entrance to TBM tunnel No. 1 (the west tunnel). This tunnel extends north to the cavern that will become the new 96th Street station, at a point just south of 92nd Street.


Walking towards the entrance to the west tunnel.

The east tunnel, which has yet to be uncovered in this section of the cavern, is behind the mass of rock to the right side of this image.


The Sandhogs working at this location I believe are installing rock bolts. The rock bolts transfers load from the exterior, to the confined (and much stronger) interior of the rock mass.


This would appear to be a sort of a "tool and parts depot" for the Sandhogs working in the cavern.

Looking South

In the distance, in the center of the image, you can see the current entrance to the east tunnel.


At this location, workers are using a MEYCO shotcrete machine to apply wet concrete to the wall of the cavern. (The current south entrance to the east tunnel is in the background.)

The shotcrete process involves pumping previously prepared wet concrete from street level down to the nozzle of the machine. Compressed air is then introduced at the nozzle to propel the concrete mixture onto the receiving surface which, in this case, is the rock wall.

The men that direct and control the nozzles on the machine are known as nozzlemen.


Another view of the same shotcrete operation. Look closely and you can see the stream of wet concrete being blasted onto the rock surface.

If you're interested in how this process works have a look at this video:
Safe and Accurate Sprayed Concrete Application For Underground Construction
MEYCO Global Underground Construction (3:11)


This view gives you some idea just how muddy the surface floor of the cavern is.


At this location, we came to a large earth moving machine that was in for repairs.


Notice the man under the machine who is in the process of repairing it. (Look for the light on the top of his safety helmet.)


The worker who was under the machine is seen here giving an interview to Ti-Hua Chang of WNYW/Fox 5.

Looking North

Michael Horodniceanu, the President of MTA Capital Construction, poses for a photographer's shot.


Further south, we came across workers who were using machines to move the blasting debris known as muck.



The muck is dumped into a large bin (shown below) that has been positioned at the bottom of the cavern access shaft.


A close up view of blasting debris being dumped into the waiting bin.


A view of the cavern access shaft. This shaft is located under the Muck House that is set up between 69th and 70th streets.

Looking South.

Now we are standing at the south end of the 72nd Street station cavern. The tunnel on the right side of this image, is TBM Tunnel No. 1 (the west tunnel).

TBM Tunnel No 2. (the east tunnel) has yet to be excavated at this location in the cavern. This tunnel is directly under the two workers in this image.

In time, the station cavern will be excavated down to the floor of the tunnels.

Looking South

A view from inside the west tunnel. The tunnel extends from the south end of the 72nd Street station to a horseshoe curve that bends to the west. Once completed this tunnel will end at a cavern that is located on the north side of the existing 63rd Street-Lexington Avenue station. (The east tunnel was completed with the TBM back in September 2011.)

It is perhaps interesting to remember that all of these photographs are really just snapshots in time. Only a handful of journalists and residents will see firsthand the new stations and tunnels in their young and raw state.

Many more New Yorkers will someday pass through the completed project areas -- blissfully unaware of the planning, engineering and physical labor involved in the subway construction. Unaware of the secrets under New York.

A Footnote:

Taking high-quality underground photographs in a tunnel or cavern is not easy. The photographer is challenged by a combination of poorly lit structures and bright construction lights, as is apparent in the image set presented above. My personal technique, shall we say, is a work-in-progress.

If you are interested in this topic I would direct you to this excellent article:

Underground Construction Photography:
Documenting a Success Story
By Susan L. Bednarz, Jacobs Associates
North American Tunneling
2008 Proceedings

On 1/19/12, the MTA released the following press release regarding the air quality in areas of the Second Avenue subway construction zone.
MTA Capital Construction (MTACC) has released results of a comprehensive study to assess the impact of blasting on air quality. The report found that most measured pollutants were below applicable national air quality and industry standards. Exceeded levels of some pollutants did not coincide with blasting and were primarily attributed to traffic emissions and other local sources.
The study was conducted by Parsons Brinckerhoff and reviewed by the U.S. Environmental Protection Agency.
"Based on the results of the study, there are no concerns that Second Avenue Subway construction is causing any danger to the public's health," MTA Capital Construction President Michael Horodniceanu said. "We will continue to do everything we can to be a good neighbor as we complete this critically important project as quickly as possible."
The monitoring program collected data for a comprehensive list of ten pollutants to capture the effects of construction activities. Ten air monitoring stations along Second Avenue (six stations located between 69th and 73rd Streets, and four stations located between 83rd and 87th Streets) collected air samples during construction activities continuously for one month from September 12 through October 8, 2011. The monitoring stations and instruments used were selected under advisement by the U.S. Environmental Protection Agency.
Measured pollutants were below air quality standards and guidance levels with the exception of some fine dust, sulfur dioxide and ammonia readings which did not coincide with blasting.
The report will also be presented at the January 26, 2012 meeting of the Second Avenue Subway Task Force Committee of Community Board 8.

A complete copy of the report can be found below.

Final Report
Air Quality Monitoring Study of Construction Activities

between 69th and and 87th Streets on Second Avenue
By Parsons Brinckerhoff

Parsons Brinckerhoff, a global professional services firm, is providing construction management services for Phase I of the Second Avenue Subway project.

Selected reports from the news media on this topic can be found below:

Report: 2nd Ave. Subway Air Safe
By Ti-Hua Chang
WNYW/Fox 5 - 1/19/12
Video (1:39)

"MTA's SAS Air-Quality Study Dismisses Health Concerns"
By Amy Zimmer - 1/19/12

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

Law Suit Filed in Case of Manhattan Stylist Killed
by Dump Truck While Crossing Street Last Year

Source: Kreindler & Kreindler LLP
PRNewsWire via - 1/19/12
The suit claims that, "a truck driver from [the] Second Avenue Subway construction project took an alternate, more dangerous route to save contractors time and money." A well prepared news piece on this tragic accident can be found on this link, "Upper East Side Stylist Run Down By Dump Truck",, 1/24/11.

"Affordable Noise"
Rent plummets on Second Avenue with never-ending construction
By Sean Creamer
Our Town - 1/19/12

"A Snapshot Of Our Times"
By George F. Will
The Washington Post

"Second Avenue Subway NYC"
By Sarah Hollins
via YouTube - 1/9/12
Video (5:49)
I project by a student of the New York Film Academy.


Anonymous said...

Many thanks for the photos and report. One minor point: in that last photo the west "horseshoe" tunnel leads to the upper (not lower) level of the Lex/63 station, unless you mean the cavern at that point is two levels high with the base on the lower level. (I assume the horseshoe tunnel has been completed.)

The Launch Box said...

Thanks for the note. You're right. I've corrected this part of the posting.

By the way, the horseshoe tunnel is not yet complete. Its my understanding that they still have about 160 feet to blast out.


Anonymous said...

Hi Christine,

Want to know how the MTA and PB could have used current air monitoring technology to better assess emissions from the 2nd Ave Subway construction?

Read now!

Matt said...

The haulage machine is known as a LHD (Load, Haul, Dump) or Scooptram in the underground mining world. So it fits well that they are being used here. Are they being run by remote control at all?

Anonymous said...

Quell surprise -- the air quality problems in the area are caused by cars and trucks!

All the more reason to finish the
Subway quickly!