In February 1989, I find myself in Portland, Oregon, at the Pine Street Theatre, a venue that sounds somewhat grander than it actually is, which is not much fancier than a room above a bar where tonight I see Cowboy Junkies play for the first time.

Their Trinity Session album – recorded in November 1987 at Toronto’s Church Of The Holy Trinity for 200 dollars – has become a Stateside phenomenon, selling 300,000 copies on its way into the US Top 30, amazing business at the time for a group no one’s really heard of before, whose music has been described as too morose for radio play.

I’ve been besotted with the record for the last few months and I’m here to write a cover story for what used to be Melody Maker, the album finally coming out in the UK. At the time, it’s like not much I’ve ever heard, although now we can hear it as an important influence on what we have since called Americana, Cowboy Junkies playing in their preferred whispering hush almost full a decade before Lambchop turned down the volume and it became cool to name-check Hank Williams, Willie Nelson and Patsy Cline.

The set that night in Portland mixes album tracks like “Misguided Angel” and “Blue Moon Revisited (Song For Elvis)” with startling versions of things like Robert Johnson’s “Me And The Devil”, Neil Young’s “Powderfinger”, the Stones’ “Dead Flowers” and, of course, their celebrated take on The Velvet Underground’s “Sweet Jane”, whose spectral hush has inspired congratulatory comments Lou Reed, who I know from experience is not easily impressed by anything he hasn’t done himself.

Nearly 20 years on, Cowboy Junkies have recently returned to the church where they recorded The Trinity Session for the Trinity Revisited album, recorded with guest appearances by Ryan Adams and Vic Chesnutt, which reworks the original template to quietly devastating effect.

And that’s the version we get tonight at the Albert Hall, as part of ATP’s Don’t Look back series – the original Junkies quartet of vocalist Margo Timmins, her brothers Michael and Peter Timmins on guitar and drums, and bassist Alan Anton joined by longstanding collaborator Jeff Bird on harmonica, mandolin and percussion, Ryan on guitar and vocals and also on vocals, a revelatory Thea Gilmore.

Amazingly, the group appear not to have changed much since I first saw them – although Margo’s mislaid her curls and Peter’s lost most of his hair – and what they play is wholly as astonishing now as it was two decades ago in Portland, Margo’s voice still uniquely spectral but with a hint more grain to it these days, here brilliantly supported by Ryan and Thea – the trio combining to especially thrilling effect on “I’m So Lonesome I Could Die” and a raw bluesy “Working On A Building”, which wouldn’t have sounded out of place on Robert plant and Alison Krauss’ raising Sand.

Ryan, looking trim and dapper in a black suit, takes the lead on a terrific version of “200 More Miles”, looking pleased to be part of all this and relieved perhaps for once not to be the centre of unwelcome attention. He also combines brilliantly with Margo on a heartbreaking “Dreaming My Dreams With You” and Michael Timmins on the squall-heavy guitar outbursts of “Postcard Blues”.

They close the show out with a brooding “Walking After Midnight”, Margo returning with Michael and Jeff Bird for a version of Ryan’s “In My Time Of Need”, from Heartbreaker, so startling in its stripped down beauty you could have heard a cat cough. Everbody’s comes back on, then, for “My Little Basquait” from last year’s At The End Of Paths Taken, and “Sun Comes Up, It’s Teusday Morning” and “Cos Cheap Is How I Feel”, two outstanding examples of Michael Timmins’ songwriting from The Caution Horses.

A stunning evening.