This week marks a year since Hurricane Sandy hit the East Coast. One of the problems persisting in New York City is keeping our transit systems from flooding. Many New Yorkers can remember walking from Midtown through a darkened city last fall while the Transit Authority was still assessing the damage -- much of it from water. Well, a company has a tech-y solution to this -- an inflatable plug that could be blown up to keep water out of a tunnel when flooding occurs. Dave Cadogan, engineering director at the company ILC Dover, tells Marketplace Tech all about the giant stopper.