Those officials were tasked with making sure the federal bureaucracy would keep operating, even if top management in Washington were disabled. It's been nicknamed a "shadow government." Detailed locations and numbers remain classified, but after the attacks on the World Trade Center and the Pentagon, hundreds of middle-management employees capable of running the vast executive branch took off for bunkers outside of Washington. Some of the places had been underground telephone company equipment hideaways. Several locations had been well-stocked for years with food and communications gear during the Cold War in case of nuclear attack. "Following Sept. 11, for a period of many months, each department was required to have some of its senior staff at alternate sites outside the Beltway," said Richard Clarke, who was working on the White House National Security Council staff on Sept. 11, 2001, and is now an ABCNEWS consultant. "That continues today, but to a lesser extent." Tweaks to Shadow Government White House sources confirmed that only a small number of federal workers are now deployed in hiding. But right after the terrorist attacks, shadow government duty could last for weeks. Workers were not allowed to tell anyone, even family, where they were. It was not without problems in the early moments of crisis. "We discovered on Sept. 11 that the continuity of government plans were inadequate," said Clarke. "On Sept. 11, it became very difficult to get out of Washington and the headquarters staffs were caught up in traffic and many of them did not arrive for a long time at the alternate sites." Since then, the White House has upgraded aging computer systems and communications in the remote bunkers, and will no longer depend on Washington workers to flee the capital. "People have been trained in Los Angeles and Chicago," said Clarke. "And in other federal departments  in case they have to have power devolve to them, in case Washington disappears without advance warning." At times of heightened risk, the precautions all the way up to the highest levels: Vice President Dick Cheney disappears to a "secure undisclosed location" so that he and President Bush will not spend the night within just a few blocks of each other.

