4 5 and 6 are partially destroyed and will not be torn down until the 1 & 9 Subway and Path lines below are secured so that heavy equipment can roll over to it's spot and begin demolition.
These buildings already are in the process of being demolished. One segment of the 1 & 9 tunnel was filled with concrete to allow heavy equipment to operate above without danger of cave-ins. Nothing of that sort was needed with the PATH tunnels, although a smaller concrete "plug" was inserted on the New Jersey side to minimize the danger of flooding.
I guess the 1 and 9 lines from Chambers to South Ferry will come on line before you know it. The PATH station is intact along with the entrances but the tunnels leading to it are flooded and caved in. One of the beams from the South Tower went through the 3rd rail! The Sation itself is not underneath the towers but the tunnels we're.
Pictures of the damaged IRT 1 & 9 tunnel and its Cortlandt Street station can be seen here
. Note that parts of the station are completely collapsed, while other parts are nearly intact (even the light bulbs are unbroken). It was this tunnel, not the PATH tunnel, that was pierced by a beam.
The PATH station suffered a partial collapse, but in general is in better shape than Cortlandt Street.
No one has yet come up with a timetable for reopening the 1 & 9 line. It is possible that the Transit Authority may rebuild it along a different alignment, as it would be more useful to the World Financial Center and Battery Park City if it ran farther to the west. No matter what's decided, the line's unlikely to reopen for another few years. PATH may reopen within two years if all goes well.