To keep the subway tunnels dry, the MTA has to plug thousands of entry points in Lower Manhattan where floodwaters can pour in. Workers at the Whitehall St. stop demonstrated the agency's current ingenuity by stacking metal logs on top of each other to seal the station. There is also a 3,000-pound door at the station that can be sealed tight with a pump — similar to doors found on Navy aircraft carriers, according to Lhota. Above ground, at the No. 1 train station on Canal St., an MTA worker with a hand crank manually pulled a flexible Kevlar cover over the staircase entrance. In addition, more than 2,000 sidewalk vents in Lower Manhattan are fitted with mechanical hatch doors.