Tuesday, August 23, 2016

Can New York City Waterproof Its Subway?

Thanks to a $4 Billion Federal Fix, MTA Is Testing Out Space-Age Flood Barriers and “Tunnel Plugs.

Stop, Do Not Enter:  A Portal Flex-Gate in action. (Credit: ILC Dover) Click to Enlarge.
Superstorm Sandy did a number on the New York City subway.  When the hurricane hit in October 2012, rain and storm surge turned impermeable asphalt and concrete streets into rivers.  Millions of gallons of seawater poured down subway entrances, manholes, and thousands of other openings to the subterranean spaces below.  Between the total devastation of the South Ferry Station (which is still under reconstruction) and the nine flooded tunnels, the metro system sustained billions of dollars in damage.

Since then, the Metropolitan Transit Authority has been spending about $4 billion in mostly federal disaster funds to repair and harden its train yards and subway tunnels.  Two of those tubes have been fixed, three more are underway, and there’s still a lot more work to come:  In July, much to Brooklynites’ ire, the MTA announced plans to shut down the L train for 18 months in 2019 in order to repair outstanding Sandy-related harm to the Canarsie Tunnel.

That’s the big, loud, delay-creating stuff.  Less noticeably to riders, the agency has also been laboring to figure out a way to seal up every vulnerable walkway, vent, and manhole before the next big storm comes.  A recent partnership with a specialized product engineering firm, ILC Dover, has yielded a bespoke flood-proof stairwell barrier that draws inspiration from both window shades and spacesuits.  It’s called the Flex-Gate—a soft cover that sits spooled in a container perpendicular to subway entrance railings, ready to unfurl, horizontally, over the entire staircase opening along built-in tracks.  It’s made from two layers of materials:  The outward facing side uses a coated fabric similar to the kind that contains gas inside spacesuits (ILC Dover has been NASA’s go-to astronaut tailor since the Apollo mission); underneath, there’s structural Kevlar webbing.

Ready to go in 5 to 10 minutes, it’s a big improvement over the crude “stoplogs” that the MTA previously used to block openings in low-lying areas.
On the first anniversary of Superstorm Sandy, Governor Andrew Cuomo inspects a tunnel plug under Manhattan’s South Ferry Station. (Credit: Flickr/MTA/Patrick Cashin) Click to Enlarge.
MTA has also tested another ILC Dover product charmingly known as a “resilient tunnel plug”—a super-tough inflatable dam that expands from a wall container to fill the full circumference of a subway tube section.  The plugs are capable of stopping not just water but also smoke and gas, handy in the event of a terrorist attack.

Read more at Can New York City Waterproof Its Subway?

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