But some construction and real estate industry executives, and some urban planners, hear echoes of the hoopla surrounding the original World Trade Center project more than 30 years ago. They are questioning whether the rapid building of so much speculative office space would have the same destabilizing consequences for the downtown market as the twin towers had in the 1970's.

Some experts are even wondering whether there will be enough steel, concrete and curtain wall to build the four towers by 2012 at the same time that two baseball stadiums, the $2 billion Goldman Sachs headquarters, the $1.7 billion expansion of the Jacob K. Javits Convention Center, Moynihan Station, 10,000 apartments and various subway projects are under construction.