It's been a long day for Andrew Klefstad. And a long four years.

At dawn, he coaxed milk from the cows in his father Roger's barn below a pink and turquoise sunrise and lush green hillsides near Ridgeland, Wis. Then he went back to work, restoring the century-old farmhouse that will soon become his young family's home.

Now it's 11 p.m., and his wife, Tiffany, is reaching up to wrap her arms around his neck, kissing him goodbye after a 90-mile drive from the farm to the Amtrak depot in St. Paul.

A duffel bag slung over his shoulder, Klefstad searches for a seat. More than 54,000 passengers last year rode this 12-hour, overnight train to the Bakken oil fields near Williston — more than doubling the passenger volume since North Dakota's latest oil boom began.

A bear of a guy at 6 foot 5 and 290 pounds, Klefstad puts in his earbuds and pulls his brimmed cap over his eyes. He's out cold before the train cuts through the darkness west of Minneapolis, falling asleep to the songs of Blink-182.

Thick arms, festooned with angel tattoos, crisscross his chest. A tiny beaded bracelet clings to his wrist. His 7-year-old son, Kelvin, made it with yellow and black beads, spelling out D-A-D amid Xs and Os, and sent it to him in Williston with a letter pleading: "Come home, Dad."

"I was like four days away from coming home," Klefstad recalled later. "I just started bawling."

Klefstad's westward train was hurtling toward a landscape like nothing America has seen for decades: Once-sleepy prairie towns now teem with high-paying jobs from a runaway economy rising up amid its lowing cattle and treeless hills.

He's part of a huge army of migrants, mostly young men, now pouring into these sparse plains where the science of hydraulic fracturing has jump-started the global energy game. Fracking is unleashing billions of barrels of oil no longer trapped 2 miles deep in North Dakota's shale.

Like gold prospectors bound for California in 1849 and their Dust Bowl descendants who followed during the Depression, or waves of rural, Southern blacks flocking northward to industrial Chicago and Detroit after World War II, today's modern migration is epic.

But it's also different. Klefstad and his ilk aren't packing up their families to escape tough times and search out new opportunity. They're part of a swinging-door, here-today, home-next-month turnstile migration.

And amid the back-and-forth lurching, Andrew Klefstad is grappling with a hard truth: This modern-day gold rush comes with golden handcuffs.

Like so many fortune seekers out here, the recession left him scrambling to find work five years ago. His father couldn't afford to pay him back on the dairy farm. Business had dried up for the industrial cleanup company he worked for in Cannon Falls, Minn.

So he lit out to North Dakota. Halliburton, the global energy industry giant, put him right to work. Now, at only 28 with no college degree, he's earning more than $100,000 a year as the general manager of Mirror Image Environmental Services. He's cleaning up spills and washing tons of sludge off the countless trucks pounding down the red-clay roads that connect the drilling rigs, nodding wells, railheads and gas flares that riddle western North Dakota.

Klefstad spends three weeks working sunup to sundown, then gets back on the train for a week with Tiffany, Kelvin and daughter Avery back in western Wisconsin. The brutal-but-profitable lifestyle leaves legions of workers juggling split lives of long hours and dislocating separation.

Klefstad insists he's out here only until the loans are paid off. His goal is to be debt-free by 40, if not sooner, something his father laughs about back on the farm.

"I have more debt now than I did at 25," says Roger, 63.

Since Klefstad began crawling into frac trucks to scour off chemicals, he has helped build his company into a player among the companies cleaning up the Bakken. He's also become a Fagin of sorts from the "Oliver Twist" story — overseeing more than a dozen kids working for him. Most are right out of high schools in Montana and Wisconsin.

For much of the year, they've crammed three to a bedroom in a ramshackle house on a leafy Williston residential block. His firm paid a staggering $8,000-a-month to rent the dump in Williston.

"There's a ton of pressure out here," Klefstad says. "If I don't win bids and get us jobs, they don't have money to pay their bills."

Oil companies now request him by name. He's earning so much money that walking away to lead a normal life back on the Wisconsin farm is as hard to do as it is tempting.

"It's a ridiculous way to live — two totally separate lives," he says. "In my dream, I would like to stay another year and get the house and cars paid for. Then I'm out of here. I don't want to spend any more time out here than I need to."

He exhales and shrugs.

"The biggest problem is I am good at this," he says. "I know it will be hard to leave."

His job: Sucking muck

From the steady line of trucks snaking south from the Four Mile Bar, a seedy landmark at the junction 4 miles west of Williston, you wouldn't know it's a Sunday morning.

"Sunday, Funday," Klefstad says.

He's steering his Cusco 28-0 "cyclone supersucker" truck, cutting south through the vast oil fields toward Dickinson, N.D., more than two hours away. To call the Bakken formation an "oil patch" is deceiving. It covers roughly 20,000 square miles — about the size of West Virginia.

The 8-plus billion barrels of sweet crude oil in the shale is not merely 2 miles deep in the earth. It's spread out beneath a sprawling swath of lightly populated terrain, ranging clockwise from northeastern Montana more than 100 miles across the Canadian border into Manitoba and Saskatchewan, then another 180 miles south toward Dickinson.

Fracking has taken the guesswork out of drilling, vaulting North Dakota into second place behind Texas in U.S. oil production. With the arrival of workers doubling and tripling populations of towns such as Williston and Watford City, the state is the fastest growing in the country.

Most workers flooding into western North Dakota come and go like Klefstad, working weeks in the oil fields before taking breaks to bring their paychecks home, then boomeranging back for more 100-hour weeks.

They spend much of their time doing what Klefstad is doing on this clear-sky Sunday morning: driving for hours between far-flung job sites. Much of the Bakken is flat and featureless, but Klefstad pilots his massive vacuum-tanker truck across a landscape of subtle beauty — climbing from rolling grasslands that suddenly turn into the canyons, ravines and buttes of Theodore Roosevelt National Park.

In Dickinson, he pulls up to a giant truck wash with towering bays off an exit of Interstate 94. Dozens of trucks deposit 20 tons a week of accumulated sludge through grates to the underground pit below.

Klefstad grabs a hard hat and a shovel and steps into a yellow hazardous-materials jumpsuit. One of his young charges, Jarred Schandelmeier of Sheridan, Mont., operates a forklift to raise the grate and connects an anaconda-size hose to the tank of the supersucker truck. The other end goes to Klefstad through the opening above the dark 8-foot-by-8-foot sludge collection cave.

Wearing a harness tethered to a cable that could hoist him out if things go wrong, Klefstad lowers himself into the pit. It's called a confined space entry.

The thrumming noise of the truck's vacuum is deafening. The smell, a noxious blend of chemicals and feces, is thick. Prairie dust from a recent dry spell coats everything.

Using what little light filters through the opening, Klefstad sucks the oily muck and grime out of the bowels of the truck wash, into his supersucker truck and eventually a dumpster out back that will be disposed of in a nearby landfill.

The work takes hours. Klefstad finally emerges — his jumpsuit splattered with ooze. Like a pig in slop, he's grinning.

"Maybe it's the level of danger, but I do love it," he says. "We keep the Bakken running."

Sometimes, his Android phone rings in the middle of the night and he wakes his crew to clean up massive, 200,000-gallon chemical spills on remote drilling sites.

Other times, it's 130 degrees in a tanker truck and Klefstad needs a full suit, an oxygen tank and a respirator for six hours.

"You come out of the confined entry caked with soot and mud, but if you love to work hard, you can make good money doing this."

That's his prime motivation.

"I don't see any reason to sugarcoat it," he says. "I don't think anybody's out here because they want to be."

An $8,000-a-month dive

The green split-level house at 1717 W. 28th St. in Williston is nestled mid-block in a nice neighborhood on the west side of town. A judge lives a few doors down. But the house is in rough shape.

The front door is barred with furniture. Exposed, clipped wires dangle from ceilings and walls. Eight oil-field workers stay here rent-free, but the company pays $8,000 a month to a series of people who have sublet it from the owner, who lives four houses down.

The whopping housing costs in Williston and surrounding towns often offset the hefty wages.

Klefstad has tried to get to know his neighbors, but they shoot back looks full of disdain, eye rolls that belie the rift between Willistonians and oil-field guys.

"They don't like us very much because we come and go at all hours of the night," he said. "But we try to be respectful."

Kayla Williams lives a few houses down with her husband, Eli, their 8-year-old daughter, Kaydance, and their dog, Marley.

"Everyone on this block is from Williston except one house, and guess which one that is?" she says. "I don't think they're rude or obnoxious, but we can only park on one side of this street and they have like six pickup trucks."

Eli, 30, grew up in the yellow house across the street from Klefstad's and purchased the corner house, pre-boom, for $140,000 six years ago. It's now valued at more than $250,000, and he makes nearly that much a year working for Weatherford, a Swiss-based oil-field services firm. So he and his wife are far from anti-oil.

"But all these guys who come out here and make good money, only to take it home, without paying taxes here or helping our schools," she says. "Well, that's a hard pill to swallow."

Klefstad's kitchen includes a large whiteboard with a grid of calendar dates, crew member names and oil-field servicing companies such as Schlumberger and Halliburton. As the boss, Klefstad has his own room upstairs. There's a large mattress on the floor, a big TV for video games and a pile of dirty clothes jammed on a shelf closet.

It's one of the few things upon which Tiffany insists: Keep your dirty clothes in North Dakota.

On this rare day off — the transmission went out in his pickup — Klefstad is down in a dark basement bedroom where three of his crew members sleep. They're removing sludge and cleaning muck. Their backpacks sit on unmade beds amid food wrappers and empty bottles of Mountain Dew.

Klefstad fiddles with the knobs on an electric guitar amplifier, creating a buzz of feedback.

"I'm not even sure who this belongs to," he says. "I think it was one of our guys who got homesick and quit and just left it after like three days."

He picks up an electric guitar and sings "Guardian Angel" from a band named the Red Jumpsuit Apparatus. His voice and strumming echo off the basement's plaster walls.

"Tiffany likes that one," he says, as the buzzing quiets.

Music brought Andrew and Tiffany together. He played tuba for the Prairie Farm High School band back in Wisconsin.

"Shhh," he says, eyes darting upstairs where other crew members are talking. "They don't know about my tuba playing."

Tiffany played French horn at nearby Clear Lake High. They were both good enough to make the all-conference band. They became good friends and began dating when she was a senior and he was a junior.

They were married on a rainy October day at their local Ridgeland church as the Wisconsin trees flashed golden and red. Kelvin, now an avid collector of frogs, made them a family, and Avery followed three years later.

'You can't build a community'

Longtime Williston Mayor Ward Koeser says "it's critical to have families here" if Williston is going to evolve with its oil industry. He says all the workers fueling frac trucks and cleaning sludge, only to depart with their paychecks for homes in Wisconsin, Oklahoma, Montana and Minnesota, leave his community on wobbly footing.

"When you have thousands of workers staying in man camps, you can't build a community," the mayor says. "You have no teenagers to work at McDonald's, no spouses to work as nurses at the hospital."

Halliburton and others have started building fully furnished townhouses to woo families to join their oil workers, convinced of the Bakken's staying power as new government studies insist there's at least twice as much oil under North Dakota as earlier predicted.

But Klefstad shakes his head at the notion of bringing his family here. Though he recently moved into a newer townhouse, he bristles at the thought of Tiffany walking through the aisles at the Williston Wal-Mart, where oil-field workers have been known to leer — or worse.

"I just can't see having my family here, and no way would I let her go to Wal-Mart — it isn't safe enough," he says. "It just doesn't seem like there's any type of connection with anybody. Everyone is here for their own self, doing their own thing and then going home."

He speaks from experience. Andrew and Tiffany tried it last year, moving the family to Billings, Mont., from June to October. Kelvin, diagnosed on the autism spectrum with Asperger's, struggled before Montana teachers shrugged and told Tiffany there was nothing they could offer her or her first-grader.

"The schools sucked, and we missed our community," Klefstad says. "I was working all the time, so it's not like we could go out and meet new friends."

Finally, Tiffany said, "That's it: We're going home."

Andrew's physical stature can be intimidating, but when a wife half his size makes up her mind, their power balance becomes clear. He didn't even try to talk her into staying. They packed up and returned to Ridgeland, where most of the neighbors attended their wedding. Kelvin is thriving in a smaller classroom. His teacher? Andrew's sister, Beth Comstock.

Panic attack at rainbow's end

For the first few days of his three-week stints in North Dakota, Klefstad is constantly on his phone, Google-talking with Tiffany about the house, the kids, the well. Then he'll get busy on a project and the phone time dwindles.

"All of a sudden, I disappear into work mode for two weeks and then I'll stop myself and say, 'Hey, I'm going home in three days …"

The psychological roller coaster, he says, is more wearing than the physical toll of his job. Back in Ridgeland, Tiffany is too busy to fret. She's chasing the kids, getting the well connected, painting Avery's room in a princess theme with glow-in-the-dark dragonflies and sparkled pink and purple walls.

"I look at this as something Andrew likes to do and does a really good job at," she says. "I just keep thinking there's a light at the end of the tunnel here, and it's coming shortly. Even if you don't call a couple years short, it's short."

The kids miss their dad but they've grown up with him being away in North Dakota, so that's all they know.

"I've missed so much that I'm never going to get back," he says. "But I've got my part to play and she's got hers."

They talk, Andrew and Tiffany, about where they want to be five and 10 years down the road. When Tiffany said it would be nice to be debt-free by 40, Andrew said: "I can do that. And I will."

As summer trains grew crowded with vacationers, Klefstad persuaded his company to start springing for sleeper compartments on the rides home from Williston. Tiffany picks him up with a long hug around 7 a.m. and it's back to the pot at the end of this rainbow.

They plunked down $85,000 of sludge cleanup money to buy the abandoned farmhouse on 2 acres a couple of miles from his folks' dairy farm.

The carpeting recently went in. The kitchen is finished. The well is hooked up.

"It's way laid back out here with a different stress all its own," he says. "I have to remember I'm not just around guys. There's my wife and kids, and I have to be more reserved and not just be the beast I can be out in the wild, wild West."

On the day he's scheduled to return, Klefstad can feel a weight on his chest.

"I look at the clock at 8 at night and go through a little panic attack," he says. "The train is coming in three hours. It's just ridiculous. I can't believe I'm doing this again."

But there he is at 11 p.m., hugging Tiffany farewell and stepping from a darkened sidewalk into the train station in St. Paul. He'll sit alone until his westbound train pulls into the station for another trek — and another paycheck — amid the sludge and spills of North Dakota's oil fields.

Curt Brown • 612-673-4767