The MTA is testing a new inflatable plug intended to seal off subway tunnels during major disasters, several months after the system was crippled by historic flooding during Sandy.
On Thursday, officials said they tested one of the 30-foot-long plugs at the South Ferry station in Manhattan, which was flooded up to the ceiling after the October storm.
Eight subway tunnels were flooded during Sandy when sandbags and plywood failed to keep millions of gallons of water at bay.
Officials said the 108-year-old system had never faced such devastation.
"We don't have to wait for space-age solutions or rocket-science solutions," said Tom Prendergast, the incoming MTA chairman.
The MTA still needs billions to fix the damage sustained at the South Ferry station during Sandy, which includes ruined electronic equipment.
Prendergast said there are 540 places in Lower Manhattan where water can get into the system, including stairways, ventilation grates and emergency exits.
He said the MTA hopes to have some mechanism in place to plug them up by the end of the 2013 hurricane season or at least by the beginning of the 2014 season.
Should a hurricane come in the meantime, he said, "we would do what we did last time, which is sandbags and plywood."