As the final night of the Railroad Revival Tour drags into the early-morning hours in New Orleans' French Quarter, the music shows no sign of stopping. Mumford & Sons, Edward Sharpe and the Magnetic Zeros, and Old Crow Medicine Show have just spent a week traveling across the country on a train of vintage Amtrak cars, playing half a dozen shows along the way for more than 32,000 fans. And, except for the few hours a day when they were eating, playing late-night poker games or sleeping, all they've done is jam. They jammed onstage, backstage, under a tree in Austin, on an Oakland street corner and anywhere else they set foot. The horn players' lips are swollen from after-hours funk sessions in the "Pony Express" car, where they'd play, drink and dance until the sun came up. "There's a lot that could go wrong," an excited Marcus Mumford, the band's front-man, said before the journey. "The train could break down. And it's a very slow train – it's a slow train coming!"
Since the Railroad Revival Tour was conceived, the Mumfords have exploded in popularity – following their Grammy performance with Bob Dylan in February, the U.K. foursome's debut LP, Sigh No More, hit Number Two, its sales pushing past a million more than a year after its release. "As amazing as the last couple of years have been, because of the schedule sometimes creativity suffers," singer-keyboardist Ben Lovett says. "On the train, you've got all these instruments lying around and you can play any time of the day. The downside of touring has gone out the window."
In New Orleans, the musicians persuade the house band at a tiny dive called the Apple Barrel to let them play for a while – and when the band demands its stage back, Mumfords, Zeros and Old Crows gather in the street and keep playing. "This is the most music we've ever played on tour," says Lovett. "There's a lot of musical brotherhood, and it's like a release." Both onboard and onstage, the musicians trade instruments and bands – and each show closes with an encore of more than 30 of them tearing into a rowdy Dixieland rendition of Woody Guthrie's "This Train Is Bound for Glory," featuring horns, fiddles, banjos and even dueling accordions.
The cinematic backdrop – a cocktail car that looks like a set from Mad Men, the parched rural tableau of Marfa, Texas, the shiny silver train rumbling down the tracks – added to the sense of excitement about having it all chronicled by a film crew. A Railroad Revival Tour movie is due later this year, directed by Emmett Malloy, who has made music videos for Jack Johnson (whom he manages), Vampire Weekend and Metallica, and also directed last year's White Stripes tour documentary, Under Great White Northern Lights. Modeled after the 1970 Festival Express train tour across Canada, featuring the Grateful Dead, Janis Joplin and the Band, the tour was conceived by Dave Conway, founder of Web broadcaster Little Radio, to encourage collaboration between the bands and explore alternate ways of taking a rock show on the road. Along the way, the Railroad Revival turned into a massive rolling party, its 15-car load packed with 130 passengers, including actor Jake Gyllenhaal – a friend of the Mumfords who jumped onboard in San Pedro, California, without even a change of clothes.
The journey kicked off in Oakland as the train pulled out just after midnight. The music car had an open bar to keep the jams whiskey-and tequila-fueled; there was catering in the dining car and Texas Hold 'Em in the observation deck of another. On Easter Sunday, the jam car even turned into an improvised church, with a small congregation gathering to watch Old Crow Medicine Show co-front-man Ketch Secor's father lead services, with members of the bands reading Bible passages and singing hymns. "It's not just the music," says Lovett. "There's no feeling of segregation between the musicians and the friends and everyone who's doing everything else on the train. It doesn't feel like three bands separately furthering their audience fan bases or any of that shit."
Secor says that when the Zeros' manager called to invite them on the tour several months ago, "it felt like we had all had a ticket burning in our pockets for a long, long time." But as excited as they'd been to take the trip, the reality of it surpassed their expectations: "I feel in an altered state on that train," he says. "It's like the gods dropped down some kind of manna, and we're having a feast together. Maybe the folk music is one common denominator, but it's much deeper than that."
In New Orleans, Edward Sharpe and the Magnetic Zeros frontman Alex Ebert walks the riverfront, reflecting on the journey. "It's only seven days, but it happened as soon as we stepped on the train," Ebert says. "As soon as we stepped on, the magic began." The Zeros are about to go into an L.A. studio to finish work on the follow-up to their hit debut LP, Up From Below, and the singer says the Railroad Revival rekindled the excitement his band felt when it was just starting. "There's something so beautiful about it, and I don't even know why," he says. "It's just a bunch of bands that got on a train to do a tour, but there's so much hope in it."
"It's like a dream only a kid would really try and make happen," he adds. "It's an end unto itself, it's a thing unto itself, it's a realization that doesn't need any furthering."
This story is from the May 26th, 2011 issue of Rolling Stone.