The floodwaters that poured into New York's deepest subway tunnels may pose the biggest obstacle to the city's recovery from the worst natural disaster in the transit system's 108-year history.
Critical electrical equipment could be ruined. Track beds could be covered with debris. Corrosive salt water could have destroyed essential switches, lights, turnstiles and the power-conducting third rail.
Several tunnels that carry trains beneath the East River remained flooded Tuesday. The head of the Metropolitan Transportation Authority said it was too early to tell how long it would take to pump them dry and make repairs.
There has always been flooding in the tunnels, which collect storm water constantly, even in the lightest of rains. Authorities said there has never been anything like the damage inflicted by Hurricane Sandy.