WITH U.S. TROOPS IN SAUDI ARABIA -- Need a missile part overnight? Or a fighter jet engine that absolutely, positively must arrive by the end of the week?

Dial Desert Express.

The U.S. military, plagued by a bureaucracy that can lose equipment orders even in a near-war emergency, has created its own special-delivery mail system for those critical, war-stopping spare-parts problems.

"It's the Federal Express of the Military Airlift Command," said Col. Steve Koons, commander of the Saudi-based area support team that oversees the Desert Express operation.

While most equipment ordered requires at least 10 days to begin wending through the supply lines from the United States to Saudi Arabia, the Desert Express team said it has cut the time from the moment the order is placed until it arrives in Saudi Arabia to as little as 72 hours.

Every afternoon, a giant green Air Force C-141 transport plane from Charleston, S.C., touches down on an airfield in eastern Saudi Arabia packed with pallets of the most urgently needed parts and equipment to support the U.S. military buildup on the Arabian Peninsula.

Crews scurry onto a nearby parking apron, stripping the plastic wrap off the pallets and sorting dozens of IBBs and GBBs -- Itty Bitty Boxes and Great Big Boxes, in the parlance of the work crews.

"We usually have no idea what's in the boxes," said Koons. "Most are small. The largest weighed 2,860 pounds -- an aircraft engine."

About 100 people, from airplane pilots to truck drivers, are assigned to the operation. The military is also beginning a second express airlift service from Europe to help support the second wave of troops en route to the Arabian Peninsula.

At the Saudi air base, a long line of trucks inches to the Desert Express loading area, each assigned a distant desert destination where the system sometimes slows to a crawl on dusty backroads with few markings.

"It's still a chore finding out where everybody is in this country," said Lt. Todd Essig, who directs the loading operations. "They are spread out."