THE TRAILER PARK Boys episode currently in production could be called Trains, Flames and Automobiles.

On Tuesday afternoon, Ricky, Julian and Bubbles (a.k.a. actors Robb Wells, John Paul Tremblay and Mike Smith) are camping out in the parking lot at Cole Harbour Place, nursing a roaring fire next to Ricky’s infamous dilapidated Chrysler New Yorker (a.k.a. The S**tmobile). For the sake of the show, the Forest Hills recreation facility is disguised as a civic centre in Bangor, Maine, complete with American flags, and the boys are gearing up for a model train convention hosted by hard rock icon Sebastian Bach.

Yes, in that twisted blend of innocence and bad behaviour that Trailer Park Boys does so well, the former Skid Row singer has been transformed into the poster boy for model railroading. So while Ricky plots to smuggle cheap American smokes back over the border and Julian downs another rum and coke, Bach sits in a director’s chair behind the camera next to director Mike Clattenburg, cracking up every time Bubbles screams his name.

"Sebastian (expletive deleted) Bach!" yells Smith in his patented Bubbles screech as he passes by on his way to back to his trailer.

"It’s all about where you put the (expletive deleted)," beams Bach, looking every inch the rock star in a spark plug silk-screened T-shirt and cascading blond hair.

Bach’s guest star turn is one of the highlights of Trailer Park Boys’ seventh season, currently halfway through shooting 10 episodes in 40 days. As in years past, Clattenburg will edit the shows over the fall and winter for a season launch in April. Between now and then there’s also the release to theatres on Oct. 6 of the feature film Trailer Park Boys: The Big Dirty and the hope that TPB-mania will finally catch on big time south of the border.

Plus it doesn’t hurt to gain the cachet of all-star fans like Bach spreading the word about the show.

"I told Axl Rose about the show when we were on tour in Europe with Guns ’n’ Roses," Bach tells Clattenburg between takes. "He needs you to send him some copies. When he gets into something, he just goes for it."

"Can you imagine Axl Rose on Trailer Park Boys?" muses Clattenburg. "We could do a special where the boys go out on the road. We can fly out to wherever he is.

"I know they have trailer parks in California."

Until that happens, Bach is probably the biggest star to visit the show yet, following in the footsteps of Rush guitarist Alex Lifeson and Cape Breton songstress Rita MacNeil. This year also promises appearances by Pictou County country star George Canyon as a forest ranger and Mamas and Papas founder Denny Doherty. The few days he’s in Halifax are an act of pure fandom; Bach was turned on to Trailer Park Boys by fellow Canadian metalhead Brian Vollmer of Helix (who’s also appeared on and been referenced on the show), and later found bootleg DVDs of the show in a New York City comics store and was immediately hooked.

"I heard he was a fan, so I called him up and told him we had an idea where he would be endorsing model trains, and he just said, ‘Hell yeah! I’d love to do it!’ " says Clattenburg.

"When he shows up it turns out he knows every episode, knows every line in the show."

For Bach, who was born in the Bahamas and raised in Ontario, the appeal of the show was instantaneous.

"This show IS Canada," he says of the characters and their low-rent take on family values. "It’s very much like growing up in Peterborough.

"And it’s a very rock and roll show; it has a very rock feel. There really should be a musical episode. I mean, I heard that Alex and Geddy (Lifeson and Lee, from Rush) are doing a song for the movie soundtrack. That’s amazing!"

While Bach has recently been stretching his acting chops on Broadway, where he appeared in a musical version of Jekyll and Hyde, and in a recurring role on the hit dramedy Gilmore Girls, his work on Trailer Park Boys is closer to his role on the VH1 series SuperGroup — which also features Ted Nugent, Anthrax’s Scott Ian, Biohazard’s Evan Seinfeld and Jason Bonham — that is, playing himself.

"Hey guys! Who loves trains?" bellows Bach to a group of fans in his introductory scene, after pulling up to the curb in a canary yellow Camaro SS muscle car with the Tyson Trains rep, played by Halifax actor Shawn Duggan. Despite singing hard rock karaoke at Cheers into the wee hours the night before, Bach shows no signs of flagging energy as he pumps the air with his fists.

"Do you want the security guard to hold back the rock chicks?" an assistant director asks Clattenburg, who nods in favour of the idea. Increased activity is always a good thing.

"I’ve never looked forward to a season more than this one," says Clattenburg after wrapping the scene, back at the show’s home base and back lot at the former Cole Harbour Rehabilitation Centre. "Season six was tough; we were shooting the movie, we had no scripts ready, although in the end we came up with some really good stuff.

"This time we had three months to write, which is one month more than usual, and we’ve gotten more ambitious with our locations. The stories include some more elaborate scenarios, and even some bigger special effects."

Season six ended on a happy note with nobody going to jail for a change, although Clattenburg says everything goes to hell in a handbasket in no time flat as season seven opens. Ricky is able to grow the best dope of his entire misbegotten career, only to have the bottom drop out of the market due to an overwhelming number of new grow-ops cropping up.

Bach enters the picture when he offers to buy up Ricky’s stash, while Bubbles’ theft of a model trail turns him into an international fugitive from justice. "It’s a huge story engine . . . literally and figuratively," grins Clattenburg.

"We’re reinventing the journey of selling dope," he adds, standing on the pile of pallets that passes for a porch at Ricky’s mobile home.