Barbara Toyer calibrates a metal detector for use at a security checkpoint at Reagan National Airport. (Matt McClain/The Washington Post)

On an early Monday morning when few people were around, Virginia Sams slipped a gun-shaped object into her sock and walked through a metal detector. She took one step back and one step forward, a quick march over a battle line of sorts. The machine reacted angrily, with beeps and blinking red lights.

The Transportation Security Administration supervisor repeated the choreography again, with a few adjustments: She moved the prop up and around her uniformed body more than a half-dozen times, ending the exercise at the top of her head. The machine again loudly protested.

Lane 1 was now ready for flight-bound travelers.

While most passengers were still asleep, dreaming of Christmas puddings and holiday vacations, TSA officials were wide awake and brimming with purpose. At Reagan National Airport, the first team of the day had about an hour to prepare the security lanes before the onslaught of fliers. Three days before Christmas, during one of the busiest stretches of travel, the agency was expecting 15,000 visitors between 4 a.m. and noon, and twice as many for the entire day.

“We are looking for efficiency and making sure that everything is running properly,” Jimmy Rodriguez, a transportation security manager, said of the opening operation at the South Pier checkpoint in Terminal B. “It looks good this morning.”

Security checkpoints at National typically open at 4:30 a.m., providing passengers with a nearly two-hour cushion before the first departure of the day. (Each airport follows a different schedule, based on flights and passenger loads. Screening areas at Washington Dulles and Baltimore-Washington International Marshall, for example, are always active, to accommodate international travelers.) However, during holidays and heavier travel periods, such as Thanksgiving, Christmas and spring break, TSA officials will start the process a half-hour earlier.

Lannie Askew, a supervisor, was one of the first to arrive several minutes shy of 3 a.m. While a trio of airport cops huddled over coffee near Dunkin’ Donuts, Askew raised the metal gate shielding the secured zone, slipped inside, then lowered it. Behind him, a custodian mopped the shiny terrazzo floor, and a woman dusted the X-ray machine with a yellow rag.

Sams appeared next and immediately started to calibrate the walk-through metal detectors. Her tools of detection were simple: the metallic faux-gun and multi-step dance.

The officers follow a short checklist of responsibilities. For instance, they set up long stainless steel tables to hold the carry-on bags and arrange towers of plastic bins for the items’ quick journey through the X-ray tunnel. Their most crucial task, however, is to test the equipment that roots out prohibited items that passengers may stash in luggage or tuck into clothing.

“They are used 24/7,” Barbara Toyer, a supervisor, said of the hard-working machines, “and take a pretty good beating.”

The seven-lane checkpoint utilizes 25 pieces of screening equipment, including eight X-ray machines for luggage. To verify their working condition, Toyer filled two hard cases with different materials and sent them through for a scan. A pair of monitors displayed two views (overhead and side) of the carriers, plus the darkened outlines of distinct shapes inside the bags: round, cylindrical, matchstick, gun.

The automatic target recognition machines (three in all) single out aberrant forms on an individual’s frame. Toyer strapped on a leg brace dense with materials that, in real life, would likely lead to a pat-down and inquiry. She also tossed a black sling around her chest that resembled a beauty pageant sash. (For security reasons, the agency will not disclose the specific nature of the filler; Toyer referred to it as “test stuff.”) She entered the booth and raised her arms; the machine beamed its radio waves in her direction. A cartoonish avatar appeared on screen with yellow Lego-ish patterns covering portions of her torso and legs. The machine earned a gold star.

Over at the explosives trace detector section, a row of 10 machines that stands between the traveler and freedom, Ileana Rodriguez was wiping a pad with a special marker and inserting the contaminated circle into the portal. A red square flashed, confirming a successful analysis.

At Lane 6, however, the ETD was not properly warming up.

“That’s why you have to come in early,” Toyer said.

(When asked why she got up so early, the 10-year TSA employee said that her eight-hour shift ended before noon. Enough said.)

The first flight was to Houston, departing at 5:45 a.m. At 3:54, a vendor in a puffy down jacket passed through the screening area. More officers arrived and took their places (each lane requires nine attendants). A few minutes later, Askew asked an officer, “We ready? We good?” then added, “I don’t see too many people out there, but it’s going to be a busy day, really busy.”

Over the PA system, the robo-female airport announcer stated, “The local time is four o’clock a.m.” The TSA officers were ready. The first three passengers coasted through the assembly line in Lane 6. Only 897 more to go before 6 a.m.

At 4:27 a.m., Lane 5 was processing passengers, as were two PreCheck lanes. The queue was nearly three rows deep and set at library volume level, due to the unsocial and low-caffeinated hour. The operating-lane count soon grew to four standard and three PreCheck, with 38 officers on duty, including supervisors.

The machines were clearly functioning. Employees stationed at the X-ray monitors flagged several bags that required additional attention. The inspectors uncovered a large container of Parmesan cheese, a bottle of vitamins, a set of cutlery and a jar of relish — a holiday gift from a daughter to her dad. The young woman zipped up her bag and raced to the ticketing counter to check her carrier.

“They don’t know if my bag will make it onto the plane,” she said regretfully during her second passage through security.

By 6 a.m., the security lanes were humming along, but the biggest wave had not yet crested. The agency was expecting 1,800 passengers to roll through the South Pier between 7 and 7:30.

“We are going to open Lane 7,” Askew said in advance of the surge. “We are definitely going to need that today.”