Sgt. Anthony Williamson led a convoy of tankers along a dark two-lane road near Baghdad last October, his truck loaded with makeshift armor of sandbags and a mounted machine gun. Suddenly, in a dirt alley between mud houses, he spotted a man taking aim with a rocket-propelled grenade launcher.

"It was like a blue flash of light and it made a loud noise, BOOM!" recalled Williamson, 33. He floored it and the grenade exploded harmlessly in his dust.

For 12 harrowing months, such became a new and unexpected routine for the 547th Transportation Unit of the D.C. National Guard. The collection of electricians, computer specialists, law enforcement officers, civil servants and ex-active duty soldiers had trained at home to drive supplies and maintain trucks. In Iraq, they found themselves regular targets of insurgent gunfire.

The mission of hauling the necessities of war is a tradition for the Capitol Guard. The 547th traces its lineage to the all-black 715th Transportation Truck Company in the 1940s and through eight campaigns including the Korean War and Operation Desert Storm.

But Iraq was high-stress duty for a unit whose motto is "You Call, We Haul," and it took a heavy toll.

When the 547th arrived, many members of the Guard "didn't know what the hell an RPG [rocket propelled grenade] or IED [Improvised Explosive Device] was," said Capt. Malik Freeman, the unit commander. "People thought [the attacks on convoys were] just random acts."

The outfit, which historically has served away from direct combat, quickly learned differently.

Of the 145 troops who arrived in the Middle East last May, fewer than two-thirds stayed in Iraq for the unit's full tour, which ended last month. One was killed, about 20 were wounded or injured and another 20 went home with heart problems, hypertension or breathing difficulties. About 10 others returned on family hardship leaves.

Unlike active-duty soldiers, National Guardsmen typically stay in one location and can spend their entire military careers in one unit, which is the rule rather than the exception for the 547th. Many have met their spouses in the guard, as Williamson did, or serve with graduates of their former high schools. About 70 percent are from the Washington area.

The unit has built family ties, continues to be almost entirely black and is widely proud of its heritage.

"It's more of a family, community-type organization," Freeman said. "It was a force multiplier for the unit and the military."

The 547th hangs onto its soldiers, and, for many, home has become the 547th.

For Sgt. Stephen Bloodworth, 48, the first shock hit him as he stepped off a military plane into the 120-degree Kuwaiti heat. The next shock came weeks later when his unit crossed the border into Iraq and he saw tanks blown up and buildings blown apart.

"This is a war. It's no more games, it's time to get real," recalled Bloodworth, a D.C. Department of Public Works heavy machinery mechanic who lives in Hillcrest. "You have to get a whole new mindset."

Attacks on convoys intensified after less than a month in the country, so sandbags and a high-caliber machine gun were loaded onto 30 of the unit's 72 trucks. Traditionally, the unit's concerns had been about drivers getting enough rest or soldiers falling asleep at the wheel. In Iraq, the concern was about being killed.

Spec. Darryl T. Dent, 21, and a District resident, boarded a five-ton truck at Baghdad International Airport on Aug. 26. He was on a security detail for the mail run. The truck struck a remote-controlled explosive device 16 miles north of Baghdad. Dent was killed and Specs. Vincent Short and Kevin Lockard were wounded.

"We just kind of felt invisible in the beginning. Until Dent got hit," said First Sgt. Linda Todd, a Southeast Washington native who lives in Clinton.

As the unit continued to transport ammunition, food, water, Iraqi bigwigs and Army brass, the drivers found that the most commonplace items could be wired to explode. A Coke can, a water bottle or a paint can by the side of the road were to be avoided. A passing motorcyclist could lob a grenade.

"You didn't know if a guy was going to work or trying to blow you up," said Freeman, who came to the 547th five years ago after college ROTC training and service in the Illinois National Guard.

Even the climate posed challenges to Freeman's command, and the unit's veterans of the Gulf War taught their colleagues lessons the military manuals don't include.

They knew that the hot and sandy conditions would require more frequent filter and oil changes and that tires would wear out faster on scorching roads.

Electricians worked to fixed broken generators in the moonlight so cooks could put breakfast on the mess table. A nurse in the 547th enabled the unit to open a first aid station, where other commanders sent troops for diagnosis and treatment. A D.C. police detective and other officers provided expertise when the mission changed from pure transportation to security escort service.

Freeman said the presence of so many veteran members boosted morale.

Most of all, the veterans offered stability in the field. "Sometimes when mortars came in, my veterans would say 'that's about three miles away.' That built confidence, that someone knew what was going on," Freeman said.

Confidence was not a substitute for dexterity, or a young person's physical conditioning.

The unit's attrition rate is unusually high, according to a National Guard spokesman who checked with comparable outfits, but it reflects some of the difficulties of a unit whose members are older than most active-duty soldiers and are doing hazardous duty in a punishing climate.

The median age in the 547th is 40, about 15 years older than the average full-time soldier in Iraq. The unit is made up of native Washingtonians and transients, holders of graduate degrees and GEDs. It has a D.C. police detective, a nurse and even a cable company employee who figured out how to connect satellite television in the desert.

A third of those who served last year are also veterans of the Gulf War. Twenty-five percent of the 547th are women and 97 percent are black.

"When the stuff hit the fan," Freeman said, his unit got the job done. When colonels went out the gate, they wanted the 547th to take them, he said.

"We were known all over as the rough riders," Freeman said. "The [soldiers] were aggressive. They didn't abuse anybody, but they didn't play games either."

State Command Sergeant Major Arthur J. Williamson spent his nearly 20 years in the 547th under conditions very different from those his son endured in Iraq.

"They dealt with urban warfare. We dealt with straight-up desert combat," said Arthur Williamson, 52, a veteran of Desert Storm and father of Anthony.

In segregated Washington in the 1950s, Arthur Williamson had held his mother's hand on a street corner and dreamed of driving big rigs. But at age 14, he was an expectant father and dropped out of the eighth grade at Backus Middle School. He spent about 10 years working at a car wash, washing dishes and doing construction and delivery jobs before enlisting.

The elder Sgt. Williamson signed up in the mid-'70s, toward the end of the Vietnam War. "The National Guard was an out for me. It was a career builder for me," Arthur Williamson recalled. His enlistment led to a GED and a bachelor of arts degree; he is working on a master's degree.

The training transformed Williamson family life as Arthur began waking his boys early to make their beds with military corners. By the time Anthony Williamson enlisted in 1989, drill sergeants found he had been used to military discipline "since '76." The elder Williamson met his wife through the Guard.

He married Sgt. Major Patricia Williamson, the Guard's personnel manager. His son married Spec. Octavia Williamson after meeting her in the 547th. She now serves as a paralegal for another Guard unit.

The early days of the 547th were filled with camaraderie and dedication, Arthur Williamson said, with members working weekends without pay to take care of equipment. Those members had dreams of emulating the famed "Red Ball Express," the all-black unit credited with supplying General George S. Patton's 3rd Army during its drive across Europe to close World War II, Arthur Williamson said.

The unit also was inspired by the 715th Transportation Truck Company, a District National Guard unit that earned a presidential citation from the Republic of Korea for its service during the Korean War. That unit was disbanded in 1954.

The 547th would practice convoy maneuvers on drives to bases in Virginia and Maryland, such as Fort A.P. Hill and Fort Meade. The guard would coordinate with D.C. police, and when 50 or 60 trucks would roll from their Alabama Avenue depot with a police escort, Southeast neighbors would stop and wave.

"It was like electricity. You felt important," Arthur Williamson recalled.

After the unit was deployed to Saudi Arabia in 1990, during the buildup to the Persian Gulf War, it logged more than a million miles hauling "beams, bullets, blankets and bodies," Arthur Williamson recalled.

The members of the unit supported the soldiers of the 82nd and 101 Airborne divisions, the 1st and 3rd Army Calvary. Other troops called them modern-day "Buffalo Soldiers," referring to black units that fought heavily on the Western frontier. The only white officer was the unit's EEO officer, Arthur Williamson said.

Arthur Williamson's eyes still cloud with tears when he thinks of putting his soldiers in harm's way. His unit performed an operation the Iraq veterans did not: transporting the caskets of soldiers who died in the Gulf War.

"I experienced the aftermath of combat," Arthur Williamson said.

The 547th is home now.

Bloodworth has chopped down a dead tree in his Pennsylvania Avenue yard and attended his daughter's graduate school graduation from the University of South Carolina, after missing her undergraduate ceremony last May.

He made a "marriage investment" by taking his wife on a cruise last month, he said.

After 15 years in the Marine Corps , the Wilmington, N.C., native joined the 547th in 1999 to finish his 20-year retirement package. He said he will stay on now, although he doesn't think he would go again. "This is best tour I've ever had spiritually," he said.

Freeman had a homecoming party with his in-laws in Chicago and is getting reacquainted with his wife and 2-year-old daughter. But his thoughts remain with the six or seven soldiers who he said are in Walter Reed Army Hospital and about 30 others still trying to recuperate from injuries and mental stress suffered in Iraq.

Anthony Williamson has spent most of his time catching up on sleep -- at least when his twin 5-year-old girls, Arjazenia and Allaiha, let him rest in their Severn home. He bought a 2004 Nissan Maxima and a lot of new clothes after losing weight in Iraq.

The 547th has been his life, and it will continue to be so.

"You've got a lot of stuff in the 547th -- you got life, love. Everybody loves each other in that company," Anthony Williamson said. "That's my family."

Sgt. Anthony Williamson, with his wife, Spec. Octavia Williamson, whom he met while serving in the D.C. Guard's 547th Transportation Unit. Williamson's father, Arthur, also met his wife in the 547th.Arthur J. Williamson served nearly 20 years in the 547th before retiring as a state command sergeant major. He served in the Persian Gulf War.Above, D.C. National Guard Spec. Corey Duppins, whose arm was wounded by a bomb as he delivered mail to Fallujah last October, receives a Purple Heart. Below, Sgt. Stephen Bloodworth, who also works for the D.C. Department of Public Works, tidies his yard in Hillcrest. Of his time in Iraq, Bloodworth says: "This is a war. It's no more games. You have to get a whole new mindset."