Services Resumes Through Montague Tubes

“The job we have ahead of us is the closest thing there is to building an under river tube from scratch.”   That’s how the extensive rebuild of MTA New York City Transit’s Montague Tubes was described by MTA Chairman and Chief Executive Officer Thomas F. Prendergast, prior to the start of the massive project 13-months ago.

The tubes were opened for [N train service Sunday, September 14 and in time for the R Subways morning rush period, Monday, September 15.  In fact, the first northbound train entered Whitehall Street at 5:55 a.m. and the first train headed for 95 Street arrived at Court Street 6:16 a.m.  The opening came about two weeks earlier than expected and was a tremendous relief for the 65,000 people who ride the R Subway through the Montague Tubes on an average weekday.  The Montague Tubes were closed around the clock for the $250 million project in order to give workers 24/7 access as they replaced everything from the rails to the ceiling.  The project came in about $60 million below budget.

Sandy took an enormous toll on the infrastructure of the City’s mass transit system, but it is arguable whether any piece of transportation infrastructure was hit as hard as the Montague Tubes.  On the night of the storm, the streets of Lower Manhattan were inundated by a high water level in excess of 17 feet, driven by the record-breaking surge that washed over the seawall at the Battery during Superstorm Sandy.  Subway tunnels were flooded and the Montague Tubes, along with seven other subway tubes, were filled with highly corrosive salt water. 

The Montague Tubes were  flooded for a length of approximately 4,000 feet with water reported to the tunnel ceiling—about 20 feet.  The flooding damaged cables to Whitehall Street and Broad Street relay rooms, 48 signal locations with line and track relays, and other associated equipment.  With the flooding in the Montague Tubes, the Whitehall St. pump plant was completely submerged, rendering all of the pumping equipment, electrical feeds, and controls inoperable.  Track, third rail and communications systems also suffered severe damage.

The brine also severely damaged the tubes’ concrete walls, ceiling, duct banks and trackbed.  For several weeks after the storm, the R Subway train’s normal conduit between Lower Manhattan and Downtown Brooklyn looked more like a medium for submersibles than a pathway for subway trains.  The tubes held more than 27 million gallons of debris-filled salt water.

But by December 20, 2012, all of the water had been pumped and sufficient work completed to allow the safe operation of train service on a temporary basis.  However, it was clearly evident that permanent repairs requiring an extended closure would be necessary.

“We took a major hit two years ago.  While we were able to get our services up and running in a comparatively short period of time. the extent of the damage dictated that we would have to take our affected infrastructure down to bare bones and rebuild it from the ground up, said NYC Transit President Carmen Bianco.  “That is what we have done with the Montague Tubes.  We have worked to make it better and more resilient than it was and we have completed that work more quickly than scheduled.”

By the time the project was complete, nearly 30,000 linear feet of duct bank was demolished (over 5.5 miles), and 5,300 cubic yards of new concrete poured for their replacement.  In order to accomplish this, more than 8,650 tons of concrete were transported to the project, some by cement mixers that traveled along the rails.  The new duct banks contain traction power cable totaling more than 78,678 linear feet (nearly 15 miles).

Prior to Sandy, the figures for removal of damaged duct banks and installation of the new systems could be measured in the scores of feet.  The complete replacement of four individual duct banks, each measuring 7,000 feet was unheard of.  Of course, this was a tough job complicated by the obvious limits on workspace.  With several different tasks, it was vital that a tremendous amount of work be accomplished by a small army of workers in an extremely limited envelope.  

“Sandy took an enormous toll on our infrastructure and from the beginning, we realized that the job we had ahead of us would rival the original construction of the tubes nearly 100 years ago,” said John O’Grady, Program Executive,  Sandy Recovery and Resiliency.  “We worked hard to return this vital link to our customers as quickly as possible.” 

WHAT WE ACCOMPLISHED

·         Constructed 30,000 linear feet of new duct banks, containing more than 78,000 feet of power cable

·         Installed 11,000 feet of new track and associated hardware, including resilient rail fasteners designed to provide a smoother ride

·         Installed 5 new track switches

·         Replaced 105,000 linear feet of communication cable, 34,000 feet of antenna cable, and 35 emergency alarms and telephones

·         Installed three new pumps capable of removing more than 1,900 gallons of water per minute, as well as 8,000 feet of pump discharge line

·         Installed emergency pump control at higher elevation

·         Installed 37,000 linear feet of new tunnel lighting cable with 1,300 tunnel lights

·         Installed 59 new valves and fittings on the existing wet fire line in the tunnel

·         Installed 295,000 linear feet of signal cable, 5 switch machines, 53 stop machines, 60 junction boxes, 33 track cases and 60 signal heads

·         Installed new Signal room with 18 cabinets at higher elevation

The Montague project was part of a multi-year catalog of post-Sandy work.   Similar construction and mitigation was recently completed at the Greenpoint G Subway and similar work is planned for other under river tubes.

Additionally, preparations have begun for the full rehabilitation of the new South Ferry Terminal, swamped beneath 80 feet of water and out of service for the past two years.

Work is also underway to harden the entrances to seven low-lying Lower Manhattan subway stations.  Flood prevention and mitigation methods will be installed at the entrances to Rector St 1 Subway, Rector St R Subway, Broad St J SubwayZ Subway, Bowling Green 4 Subway5 Subway, Whitehall St R Subway, South Ferry 1 Subway (currently closed), and the Old South Ferry Loop Station 1 Subway