• Bow Thayer and Perfect Trainwreck

Perfect Trainwreck front man Bow Thayer — who thinks he’s 46 but isn’t sure — says he began the Tweed River Music Festival out of frustration. “It was pretty much impossible to get into the bigger festivals like Bonnaroo or Gathering of the Vibes without being represented by Live Nation,” he says, referring to the behemoth promotion company that’s presently trying to merge with Ticketmaster. Instead of paying exorbitant traveling costs just to play early, sideshow sets to a middling audience, Thayer thought, why not host his own summer fest featuring local, unsigned bands?

His answer, in 2009, was the Tweed River Music Festival, which is set to begin its fourth annual three-day run this Friday, August 3. Thayer says he expects bigger stages and video screens will help make the festival “more pro than ever,” though he intends to keep the capacity at 2000, and the location on the banks of the Tweed River in Stockbridge, at the junction of routes 100 and 107.

Tim Gearen and Andrea Gillis are two of the festival’s longtime musical staples. A songwriter from Boston who says her sound is somewhere between Mahalia Jackson and Eddie Money, Gillis considers Tweed “just the greatest.”

“In Boston,” she says, “I’m always playing on the same night as someone I want to see. At Tweed, you get to see all of your favorite bands in two days.”

Thayer takes pride in his festival’s diversity. “We’re not just like a roots festival or a blues festival or a jam-band festival or a bluegrass festival,” he says. “We got it all.”

Roadsaw, a Boston-based metal band with a steady European following, exemplifies Thayer’s claim.

Josh Hager, formerly of the Elevator Drops, is also slated to offer mellow, end-of-the-day head-bobber tunes with his current band, Garvey J. and the Secret Pockets of Hope and Resistance.

Other festival highlights include Township (bona fide bell-bottom rockers), Waylon Speed (Vermont speedwestern outlaws) and Caravan of Thieves (playful gypsy boot-stompers). Thayer says he makes sure that all bands are paid and well fed, and have all the beer they can drink.

“I have to say,” says Gillis, “they don’t really skimp on anything. They treat their friends like gold.”

Thayer’s own Perfect Trainwreck anchors the festival. The Stockbridge-based band materialized in 2007 after Thayer had drifted for years from band to band, trying to make it in the Boston music scene.

“I felt like I was playing music just to fit in with a bunch of other bands,” Thayer says. Inspired by the Band, whom Thayer considers “a bunch of freaky dudes that moved up north to make music,” Thayer absconded to Vermont in search of a new identity.

After rigging up and striking down a notable country-grunge band called Elbow, Thayer founded the Benders, who scored a hit, “Mountain Radio,” on the HBO show “True Blood.” The Benders last played at the 2010 Tweed River fest, reuniting for one night only.

While the Benders played rapid, jug-sluggin’ bluegrass, Perfect Trainwreck defy simple classification with thoughtful tunes that don’t necessarily sound like the Grateful Dead but are certainly inspired by that band’s mid-career studio work.

Other Trainwreck members are Jeff Berlin on drums, Jeremy Curtis on bass, Chris McGandy on pedal steel and James Rohr on piano.

The band recorded its forthcoming third album, Eden, at Thayer’s recently finished home studio in Stockbridge. His was modeled after Band member Levon Helm’s studio, which is where Trainwreck recorded their first release, Bow Thayer and Perfect Trainwreck. The late drummer and vocalist also lent his iconic ones and twos on Thayer’s solo album, Spend It All.

Eden is a follow-up to Trainwreck’s 2010 album, Bottom of the Sky, though the former’s lyrics venture further into politics and social concerns.

“It’s going to be a very epic, kind of thematic record,” Thayer says, though he’s quick to add that the album isn’t preachy. “It’s all based on the notion that, as we live here on Earth, we’re living here in Eden, and we’re creating a scarcity out of an abundant society.”

Though Eden won’t be available until January, Thayer plans to satiate his fans with the reunion of another bygone band, Seven League Boots, who will release a remastered copy of their album 12 Songs at this year’s Tweed.

SLB served up much punkier fare than have Thayer’s other projects, and shared stages in the ’80s and ’90s with Bad Brains, Fugazi, Green Day and Pearl Jam. According to Thayer, Rage Against the Machine cited SLB as an early influence.

“We disbanded before we had a chance to shine,” Thayer laments. “We just couldn’t keep it together, because we were young and stupid.” The band members’ reunion will mark their first time playing together — or even seeing each other — in 20 years.

Also on Thayer’s docket is Hindsight, a celebration of his last 15 years of songwriting in Vermont. The record will be sold exclusively at the festival prior to its August 7 release to the public.

Unlike last year’s Tweed, which hosted famed soul man Booker T., the 2012 fest won’t boast quite such a big marquee name.

“Booker did us a solid by playing our festival for less than he usually gets,” Thayer says, “but it was still very expensive.” To get the festival out of debt, bands volunteered to play for free at a Winter Tweed, held at Pico Mountain last March.

The absence of a nationally renowned name simply underscores an essential value of Tweed: that great bands are close at hand.

To show festivalgoers just how much fun they’re having, a doc shot last year by Grey Sky Films, Tweed River Music Festival: A Documentary, will debut this year, as well. Newcomers and “Tweedies” alike can catch a sneak peek on the festival’s website. Judging by the enticing clips of cold streams, hot grills and tents stretched out over sweeping, verdant fields, Tweed seems the perfect place to watch a Trainwreck.

Tweed River Music Festival, Friday, August 3, through Sunday, August 5, in Stockbridge. $40/100/140. AA. tweedrivermusicfestival.com