Hipsters, beware: there's a hugely popular act that's been packing arenas of late, but you won't be hearing about it on Pitchfork or in Harp and Alternative Press. There's no emo, screamo, or dreamo involved, just heavy doses of Christmas-themed rock opera. As guitarist Al Pitrelli admits over the phone before heading to a sound check in Fresno, California, the success of his decidedly unhip ensemble, the Trans-Siberian Orchestra, goes against all odds.

"You're correct, rock opera is not that popular right now," he points out. "But about a dozen years or so ago, Paul O'Neill, Bob Kinkel, Jon Oliva, and myself just sat down and said, 'We want to make a record that's representative of all four of our musical backgrounds.' It's not like we were trying to write a record that was current, or get on the charts, or keep up with kids 20, 30 years younger than us.

"I think what happened is that the community that listens to TSO just gets the honesty of it," he continues. "You know, when I was growin' up there was something just real honest about that music. When you listened to [Alice Cooper's] Billion Dollar Babies, that was a record that made no sense, but it was a masterpiece. And when you listened to Blue Oyster Cult or the Allman Brothers or AC/DC, they were just writin' stuff that they loved, and if the population took hold, then great."

Pitrelli first collaborated with O'Neill, Kinkel, and Oliva–the other core members of TSO's creative team–while he was a member of prog-metal group Savatage, which released 11 studio recordings between 1983 and 2001, mostly concept albums or rock operas. Over the years, he has also worked as a hired gun for acts like Alice Cooper, Megadeth, Asia, and Joe Lynn Turner. Before that the 45-year-old Long Island native cut his teeth in New York–area cover bands, performing a mix of Humble Pie, Bad Company, Robin Trower, Pat Travers, Johnny Winter, and Rick Derringer tunes–or, as he describes it, "all the cool stuff". But folks with similar classic-rock tastes aren't the only ones snapping up tix for Trans-Siberian Orchestra gigs these days.

"Fortunately for us, it kinda crosses every genre and every age demographic," Pitrelli says. "I mean, the first time we did a show, back in '99, we walked on-stage and there were kids with Slayer T-shirts on, sitting next to their grandmothers with crocheted reindeer sweaters. I mean they run from seven to 70, and that's the beauty of it. You go into any of the venues that we play and you see, like, three generations of families sitting together, having a great time enjoying the same stuff."

TSO's latest CD, The Lost Christmas Eve, is its fourth rock opera, and the closing chapter of the holiday trilogy that began with 1996's Christmas Eve and Other Stories. In the group's current bio, producer-lyricist and primary composer O'Neill states that The Lost Christmas Eve is "about so much more than Christmas. It's a rock album that you can listen to while driving your car."

Pitrelli agrees. "There's Christmas songs on there, obviously, and it's become part of a lot of people's Christmas traditions, but at the end of the day it's just a flamin' rock 'n' roll record. I mean, this album is pretty ferocious–as are all the records, you know, the three Christmas ones, Beethoven's Last Night–which is not a holiday rock opera–and the new one that we're working on, Nightcastle. I mean, this is as if you took Pink Floyd and Yes and Kansas and AC/DC and mixed it all together and added some elements of gospel, jazz, and country."

The Trans-Siberian Orchestra's current lineup sees Pitrelli playing with a seven-piece band, a seven-piece string section, and 10 vocalists, so at any given time there are about two dozen performers on-stage–and that's just the West Coast edition. The year after TSO's debut, popular demand required that its membership be split in two for touring purposes.

"There was physically no way to go from Boston to San Francisco overnight," Pitrelli explains. Now he and his wife, keyboardist Jane Mangini, run the West Coast ensemble, while composer-coproducer Kinkel is in charge of its East Coast counterpart. Between the large number of musicians, the immense staging, and the state-of-the-art light show–which uses extensive pyrotechnics and lasers–it's an immense undertaking to get the group's Christmas-themed stories of loss and redemption across to the public. With little or no commercial-radio play, the group counts on word of mouth to help fill hockey rinks across North America, and apparently word is getting out. The two bands will perform nearly 100 shows over a seven-week span, playing to more than half a million people.

So with his soul mate and several long-time friends along for the ride, Pitrelli must get quite the warm, fuzzy feeling from TSO's Christmas tunes, right? Not necessarily. "Christmas wasn't always a happy holiday," he relates. "So sometimes it affects me in a good way, and sometimes it affects me in a bad way. But no matter what, it kinda puts you back on your heels and makes you take inventory of the year that's gone by and what's happened–people we've lost, people we've gained.

"Christmas runs the emotional gamut, and you can hear a lot of that on our records because not all of it is uplifting; some of it is dark, some of it is sad," he continues. "And we're just not afraid to bring attention to that, saying, 'You know what? It's okay to laugh, and it's okay to cry.'"

The Trans-Siberian Orchestra plays GM Place on Friday (November 30).