At 6am on a Friday in May, Shannon Hall sat in her truck, braiding her hair into two bright blonde pigtails that would pop out from under her hard hat. She pressed play on her favorite pump-up track, Pantera’s “Shedding Skin.”

“Let’s end this one on a good note,” she said. Shannon opened the door, slipped on gloves to protect her magenta-and-matte-black nails, and, after four years on the job, headed to her last day of work building a brand-new train line.

For the past six years, crews working for Washington public transit utility Sound Transit have been digging paths and building bridges for 3.4 miles of light rail track that connects downtown Bellevue to the suburb of Redmond. This last section of track connects Redmond to a 10-mile light rail line that will eventually connect all the way to downtown Seattle. At peak commute times, trains speed by on the steel track every 10 minutes, allowing thousands of workers to leave their cars at home as they head to jobs at local employers like Microsoft.

Shannon’s a 36-year-old track laborer whose favorite task on the job is working with heavy equipment—the bigger, the better. She especially loves running the hammer for pile driving, pounding 80-feet of sheet metal into the ground. “We call it STICKY: shit that can kill you,” says Shannon. “I fell in love with working with rail. A stick of rail that's 500 feet long, and we're dragging it down the road, that thing is like a loaded gun. The minute that thing comes around the corner, wow. It's exciting. It's awesome. As long as you're not complacent, keep your head on a swivel and you're aware of your surroundings, you'll be alright.”

Shannon is experienced with harrowing situations—after all, she’s the mother of a 10-year-old. As a kid, Shannon’s family moved around a lot. She spent a decade jumping between jobs, never making much money, when her dad encouraged her to apply for union work. She passed the training, “Hell Week,” survived her first few gigs, and discovered that she loved the hard work of building rail lines. She’s now a member of Local 242 and is determined to learn everything her mentors on the job can teach her. One of the first things that an experienced journeyman taught her was how to run a core drill, that pulls perfect cylinders out of the earth.

“The first time I ran the core drill by myself I was like, ‘Oh my God. I don't know what I'm doing.’ I told myself, ‘Chill out. You can do this. You're good.’ I always told myself, ‘If you can learn one thing a day, you're going to have a whole arsenal of things that you know how to do.’” Now, after six years in the union, Shannon can do almost anything. “I’m a jack of all trades when it comes to construction.”

Every day on the rail line project, crews worked together to chip away at the massive task of constructing a new train line through an unpredictable landscape. Dillon Downey started on the project from the very beginning, working in the literal trenches on the rail line for six years. His official job title is Journeyman Laborer Foreman but he described his job as “anything to do with dirt.” Dillion has a distinctive, large bright red beard that matches the color of his hard hat. His crew had the tricky job of protecting the natural environment along the route, trying to not disturb the fish that live in the creek while maneuvering around active sewer lines and driving rebar into the earth to build bridges over the waterways. Even on dry land, when the crew drilled deep into the soil to place support pillars, they would eventually hit water. Dillon’s dirtiest day on the job came when the crew was digging a trench to lay rails and hit water that gushed out over the entire team.

“I was waist deep, shoulder deep, crawling through mud. I was shroomed up,” he says, meaning his skin turned to the wrinkly texture of a mushroom. “The excavators were buried in mud. We had to dig all that out.” At the end of the day, a colleague hosed Dillon off in a parking lot with a garden hose before he could get clean enough to drive home. “People see the finished work, but they don't quite see how much sweat it took to do all the work,” he says.

While commuters will see only the shiny white-and-blue Sound Transit trains and clean concrete stations, the workers know what toll the heavy labor takes. “At the end of the day, I'm sore. I'm tired,” says Shannon.” By the time I make it home, it's time to take a shower, make dinner, pack lunches, and spend a couple minutes with my daughter.”

As grueling as the work is, both Shannon and Dillon have enjoyed it and feel mixed emotions about the rail line’s grand opening. “I've been here for four years and it kind of breaks my heart that today is my last day here. It’s like watching your children grow up,” says Shannon. Before the transit line opened to the public, the work crew got the chance to ride on it and preview what tens of thousands of people would soon depend on every day. Shannon spent the ride staring out the window. “I'm not a quiet person and the whole time I was in the little seat by the window, I was just so quiet,” she says. “The ride was so smooth and the train was hauling ass down the track. I was like, ‘Dude, we built this. Wow.’”