From left, Americans Mick Dierdorff and Nick Baumgartner trail the pack in the snowboard cross final Thursday. (Kin Cheung/AP)

The plumber, landscaper, carpenter and concrete pourer came from different corners of the United States, sharing blue-collar backgrounds, sneaky athleticism and an affinity for lunacy. They formed the U.S. snowboard cross team at the PyeongChang Olympics, a quartet of maniacs who play demolition derby on snow for kicks and work proletarian gigs for a living.

“I guess we could all build a house together, if you wanted,” said Jonathan Cheever, who back in Saugus, Mass., is a plumber, and who on Monday at Phoenix Snow Park wore bib No. 21 and came within .004 seconds of advancing out of his first-round heat.

They won no medals. Hagen Kearney (landscaper and guitar player for a metal band) spilled in a quarterfinal. Nick Baumgartner (concrete pourer) and Mick Dierdorff (carpenter) recovered from midrace spills in the semifinals and still finished second and third, securing the last two spots in the final, where they would finish fourth and fifth, just off the podium.

The results embittered none of them. They were all happy to make the Olympics, especially to make them together. Baumgartner, the oldest racer in the field at 36 and competing in his third Olympics, mugged for cameras at the end of every race and at the end circulated for half an hour with his arm around his 13-year-old son.

“If you ask me,” Baumgartner said, “this is the coolest sport on the planet.”

In snowboard cross, snowboarders race six at a time along bumps, hills, curved banks and, at the end, three massive jumps. It is a combination of downhill skiing, NASCAR and Russian roulette. Winter Olympians are not like the rest of us, and snowboard cross racers are not like the rest of Winter Olympians.

After his race, Cheever stared up at a video screen showing the race, saw a Russian racer crash on the penultimate jump and screamed, “Oh!” Cheever explained that some snowboarders had asked race officials to make the jump bigger to reduce speed and decrease the amplitude racers were achieving, which was surpassing a terrifying 40 feet.

“If you miss your move by a little bit, you might be getting pulled out on a stretcher,” Cheever said.

It seemed, to a novice, as if the course might have a design flaw. Was that jump, the one that could turn a small miscue into an ambulance ride, too dangerous?

“As far as the danger goes, nobody would be doing this sport if that didn’t get them off a little bit,” Cheever said. “The last time I had these feelings snowboarding, I was in Alaska — Cordova — and it was no-fall zone. Like, you fall, you’re probably not going to come back from it.”

See? It’s not such a treacherous sport: When you crash in snowboard cross, at least you will survive.

Baumgartner is nothing if not a survivor. In December, on his birthday, he competed in a World Cup race in Austria. Coming out of a corner, he collided with an Italian racer just before a jump. He landed on his back on an uphill slope, the worst-case scenario. He suffered a compression fracture to two vertebrae, broke a rib and bruised both lungs. Medics loaded Baumgartner into a cart.

“People are going to ask me, ‘When did you start feeling old?’ ” Baumgartner said. “About noon on my 36th birthday.”

Immediately, he thought about the Olympics, less than three months away. He told the doctor, “This isn’t good.” When he stood up, he didn’t collapse, so hope returned. A couple of weeks later, at a race in Turkey, he qualified for the Games.

The four racers who made the team trained together, meeting up for a week at time in Park City or Argentina, building start gates and maintaining the courses themselves. Baumgartner, who is from a map dot in the Upper Peninsula called Iron River, Mich., sometimes wears his Olympic ring on the job, and so when an acquaintance tries to tell him how famous he is, he points to the concrete stuck to the ring.

“The coolest part about that is sharing that with other people,” Baumgartner said. “If you don’t think you can do anything from where you’re from, you got to be kidding me. You can do anything you want to do.”

“We all have such love for each other,” Kearney said. “I think a lot of people didn’t expect to see us four making it to the Olympics. I don’t know. We have this special, unique thing that’s hard to describe. We’re just a bunch of idiots having fun.”

Fun. That would be one way to describe the semifinal Baumgartner and Dierdorff raced. It was an ode to mayhem.

Baumgartner tumbled early in the race, which typically would doom him — oftentimes, the three racers who finish are the racers who advance. Falling first this time, though, was his great advantage. When others crashed up ahead, the sequence allowed him to cruise past. When he finished comfortably in second, Baumgartner shouted at the crowd, “Somebody upstairs loves me!”

Later, he learned what craziness allowed him to cross the line second. Dierdorff made it through the first turn in prime position, riding fast and strong, gathering speed. Heading into a small jump, a racer bumped him from the side. “Next thing I know, I’m flying through the air, landing on my back in the middle of turn two,” Dierdorff said.

Dierdorff’s back throbbed, such that at the end of the day, he weighed whether he ought to undergo an X-ray. But a central tenet of the sport, one he had learned when he began at age 12, ran through his head: The race is never over. Always get up and finish.

So Dierdorff rose, even though he believed for certain his Olympics was over. Then he came over a jump and saw one rider down, “so I just started sending it, anything I could do to keep rushing down the course,” Dierdorff said. He glided over another bump, his back still smarting, and saw the aftermath of yet another crash.

“I don’t even know what was going through my head, but I saw bodies piled up,” Dierdorff said, authoring an accidental summation of his sport.

Dierdorff continued speeding down the course, uncertain how much human carnage he had ridden past. Flying over the final jump, Dierdorff heard the crowd roar and saw only two opponents, Baumgartner and a Spaniard, standing in front of the grandstand. He realized he had made it through. “Wow,” he thought. “Did that really happen?”

“That was one of the wildest heats of my life,” Dierdorff said.

The final brought no such drama. Frenchman Pierre Vaultier, a rider so great he can establish an early and sizable lead, then use the space to immunize himself from chaos, defended the gold medal he won in Sochi. Dierdorff and Baumgartner remained behind the top three finishers for the entirety of the course, never threatening.

Still, both wore huge smiles afterward. Dierdorff still could not believe how he had made the finals of the Olympics. Baumgartner boasted he had missed out on gold, silver and bronze, but he had won the “wooden spoon.”

Baumgartner limped to the grandstand to hug family and friends. He retrieved his 13-year-old son, Landon, placed his arm around him and ushered him through television interviews and into the pen where reporters gather. Baumgartner planned to stay through Closing Ceremonies and to introduce Landon to as many athletes as possible. He was the oldest snowboarder in the competition, but he wants to keep doing this until he is 40 and compete in a fourth Olympics.

“I’ll be here in four years, absolutely,” Baumgartner said. “If I got to go until I’m 100 to get a medal, I’m going to keep doing it.”

In explaining his family life, Baumgartner mentioned he coaches Landon in soccer. Landon informed a small pack of reporters his father was “not good” as a soccer coach, based on his record. Baumgartner cracked up at the appraisal, then offered his counterargument.

“Well, yeah,” Baumgartner said. “But did we have fun?”

Landon nodded.

“We had a lot of fun,” Baumgartner said. “So it was good.”