Exhausted and coated with dust, soldiers of the Army division that spearheaded the invasion of Iraq paused to regroup and rest today after a five-day race across desert that brought them and 7,000 vehicles to points within 50 miles of Baghdad.

There was little sleep or comfort for many of the soldiers of the 3rd Infantry Division, however. An intense sandstorm blew all day through a hastily built camp here, as perimeter guards watched for Iraqis and mechanics labored to make tanks battle-ready for a potentially decisive drive across the Euphrates River and on to the Iraqi capital.

It seems that everywhere in this part of Iraq, there are American vehicles -- not only tanks, but Humvees, tankers, armored personnel carriers and supply trucks. "It's the largest armored convoy in history," said Capt. Steve Hommel, 41, of San Diego, the chaplain of the division's 3rd Battalion, 15th Infantry Regiment

Commanders said it also set records for distance and speed in an advance by an armored column. The division's men and women drove the 7,000 vehicles 240 miles north from Kuwait in two days, then spent three days maneuvering into position for the push into Baghdad.

Not far from the camp, Army gunners fired barrages of artillery shells, apparently targeting the Medina Division of the Republican Guard, President Saddam Hussein's elite force. The division guards the southern approach to Baghdad and has been the target of U.S. helicopter and bomber strikes.

Top commanders of the 3rd Infantry Division's 2nd Brigade were meeting to review plans for the next phase of the U.S. drive to unseat Hussein, officers said.

For the U.S. soldiers, this was a day to "refit, refuel and rearm," said Capt. Anthony Butler, 32, of Helena, Mont., commander of the 2nd Brigade's headquarters company. The soldiers were also hoping to get some sleep.

While the booms of U.S. artillery reverberated across the dusty campsite, soldiers worked into the night to fix M1 Abrams tanks, Bradley Fighting Vehicles and M-113 armored personnel carriers that have fallen victim to the long march.

Wearing goggles against the sandstorm, their faces covered with dust, Army mechanics toiled by flashlight and "chem light" to prepare the vehicles for battle. "Five layers of dirt are keeping me warm," one mechanic joked.

Between driving north and repairing vehicles along the way, some mechanics have gotten only an hour or two of sleep each night for five nights.

At sunset, the encampment was bathed in a strange orange glow, the fading daylight filtering through the swirling dust.

Barely visible from only a few yards away, soldiers clad in Kevlar vests, helmets and chemical protective suits cut ghostly figures as they guarded the camp's perimeter or walked to a Humvee to be served a hot but sandy evening meal of canned ham, eggs and waffles.

The blowing sand tends to dull one of the infantry's main advantages in fighting the Iraqis -- its night vision equipment. "NODs [night optical devices] can't see through sand," Butler said.

For many of the soldiers, the final hours were the worst. With the combination of the sandstorm, unfamiliar terrain, blackout conditions and driver fatigue working against them, about 40 vehicles of the division took 10 hours to travel 27 miles Monday night and early this morning.

After setting out at 6:30 p.m. Monday from a stopping point where they had been delayed by a mortar attack, a column of angry, frustrated and exhausted soldiers riding in tanks, Bradley Fighting Vehicles, fuel trucks, medical tracks, Humvees and other support vehicles finally joined the rest of their unit at a dusty encampment southwest of Baghdad at about 4:30 a.m. today.

"It was a test of endurance and discipline," said Hommel, the chaplain.

Drained by an armored road march that U.S. commanders said was unprecedented in size, speed and distance traveled, drivers kept falling asleep at the wheel and veering off their route or nodding off during pauses.

Soldiers following behind would fight through the blinding sandstorm on foot to wake the sleeping driver and get him moving again. Then another driver elsewhere in the convoy would fall asleep, and the cycle would be repeated.

Traveling part of the route off-road, drivers also repeatedly lost sight of the vehicles in front of them in the sandstorm and veered off in another direction.

Weighing on commanders' minds, amid the confusion, was the fate of a supply convoy whose drivers got lost in southern Iraq on Sunday and blundered into an Iraqi-held area; seven soldiers were killed and five were captured.

As Monday night's convoy moved in fits and starts, with long pauses while those in charge tried to get everyone moving at once, the frustration built to the boiling point. Angry exchanges, curses and threats of physical harm crackled across radio headsets in the darkness.

"This is not the way to project military power," one sergeant snapped as he tried to get his soldiers moving together.

"This is what you get when you go three days with catnaps and don't let soldiers get their rest," another complained.

The difficulties stood in sharp contrast to what commanders said was, overall, a highly successful march from Kuwait to central Iraq

Driving through the sandstorm over open desert and without headlights, "you couldn't see anything," said Capt. William Marm, the 3rd Battalion maintenance officer in charge of the convoy. "When guys can't see anything, they stop." Making matters worse, some of the vehicles did not have radios, making it hard to tell who was awake and who was holding up the convoy.

"I can't keep my eyes open," a bleary-eyed Pfc. David Turner, driver of an M88 recovery vehicle, told his sergeant on the radio. "I'm falling asleep while driving standing up," said Turner, 21, of Binghamton, N.Y.

The commander of an M1 Abrams tank radioed that he was lost, couldn't see anyone and was almost out of fuel. It turned out he was only a few hundred yards from the perimeter of the camp.

Upon arrival at the destination, officers called a meeting to ream out drivers who had delayed the convoy. "We basically chewed some ass," Marm said. Officers were angry because "people were sleeping, getting stuck and not letting people know they weren't moving."

With sleep deprivation taking a toll, commanders decided today would be a rest day. But even as soldiers worked to get their equipment in order, there were continued efforts, in the current military parlance, to "shape the battlefield" for an upcoming offensive aimed at toppling Hussein.

Through the early morning and into the afternoon, the booms of U.S. artillery could be heard echoing across the arid plains.

Soldiers from the Army's 3rd Infantry Division lie on the ground at a captured airfield in southern Iraq to wait out a powerful sandstorm.Sand and twilight combine to make the desert look blood-red as 3rd Infantry troops wait near Karbala, about 50 miles southwest of Baghdad.