Maybe Del McCoury missed out on the late ’60s and early ’70s, perhaps lying low in some hollow – make that “holler” – in the hills of Tennessee, letting the tie-dyed, hippie influences on bluegrass roll on past him.

To see McCoury and his band on the Railroad Stage on Saturday afternoon, each member looking as sharp as the creases in their crisp suits and ties, you might wonder if the year were 1955 instead of 2005. The band’s approach to the timeless bluegrass tunes it played was also decidedly old-fashioned, the players stepping up to a single microphone to add harmony vocals.

But rather than seem anachronistic, the Del McCoury Band’s set was stellar, serving up the elements of bluegrass that make the music so joyful, and such a natural in a live, festival setting.

McCoury on guitar and vocals was joined by sons Ronnie on mandolin and Rob on banjo, both perennial award-winners on their instruments. The group was rounded out by Jason Carter on fiddle and Dennis Crouch on bass fiddle.

The elder McCoury’s voice – a thin, reedy and twangy tenor – would have fit in well on the “Oh, Brother Where Art Thou?” soundtrack. By itself, it might have grown tiresome, but the group harmony provided a fine variety.

The set alternated vocal songs with instrumentals. And make no mistake, lest the suits deceive – these boys could play with gusto, pickin’ and sawin’ as well as anyone playing bluegrass today.

A priceless moment came in their cover of the John Sebastian tune, “Nashville Cats.” On the chorus, McCoury sang “Nash-ville cats,” then the others stepped one long stride to the center-stage microphone to add, “Play clean as country water” in four-part harmony.

McCoury asked for requests, and played a version of English singer-songwriter Richard Thompson’s “1952 Vincent Black Lightning” that could have persuaded a listener to believe the song was written in the 1940s instead of a few years ago.

Other styles have been successfully grafted onto bluegrass over the years, but for an example of the pure strain, it’s hard to top the Del McCoury Band.