AS THE RECORDING industry continues to sweat over the fortunes of disco, new wave, "power pop" and various other products of the late 1970s, a few of rock's relics, stumbling awkwardly in the background, dodge extinction and rumble on.

Several of these antiques, including Led Zeppelin and the Rolling Stones, have adjusted to current trends, trying to retain some of their grandeur, but one survivor has refused to change his tune. Neil Young highlighted 1979 with his Rust series, a three-part statement that reaffirms his faith in rock and in himself.

Young began his eccentric campaign last summer with the release of a concert film and a new album, both titled Rust Never Sleeps. The record illustrated his two-headed ability to craft folkie ballads and to spit sizzling rockers while avoiding accusations of hypocrisy. Young is serious about both styles, and his integrity defies critics who claim that he has never committed himself to one type of music. The final installment of Rust is the soundtrack of the movie, Live Rust, a double-album set which stands on its own as a summary of Young's 16-year career.

Live Rust is more than a revision or repackaging of Young's first greatest hits anthology, Decade. Most of the tracks are veterans of the Young repertoire, but he presents them with a startling power he often failed to generate in the past. Freed form the technical perfection of the studio, he unleashes the emotions that have provided the foundations for his best song-writing.

Live Rust fulfills the requirement of a live album; it reproduces the aura of the performance. Young sounds very alone on stage as he strums through the melodic "I Am A Child." He infuses all of his acoustic work with an honest urgency, conveying the innocence he once knew and the troubles he has weathered. His down-homey harmonica improvisation meshes well with unpretentious guitar and piano arrangements. When backed by the lastest edition of Crazy Horse, Young reveals his flair for the heavy decibels, and shows the rough, untarnished energy of his electric music.

Although the songs themselves are undisciplined, Young has carefully constructed Live Rust as a thematic progression, a roadmap of his journey. The tour begins appropriately with "Sugar Mountain," a song he wrote on his nineteenth birthday.

Young's voice remains confident in this version, and never wanders to the falsetto for which he is so often criticized. In fact, he belts out an unaccompanied chorus with strength and style. He no longer mourns for the lost days of his youth, but instead celebrates them.

THE ACOUSTIC FIRST SET ends with "My My, Hey Hey (Out of the Blue)"--the unaccompanied version of his enigmatic tribute to rock and roll. As he did on Rust Never Sleeps, Young repeats the song later with the enthusiastic aid of Crazy Horsemen Frank Sampedro (rhythm guitar), Billy Talbot (bass) and Ralph Molina (drums).

Perfect execution has never been Crazy Horse's aim, but their pounding and buzzing are ideal for Young's meandering, jam session-like electric productions. The foursome strut through a sterling performance of "When You Dance I Can Really Love" to open the second set, and they render "The Loner" with equal abandon. Young sings of realm far away from the serenity of the Sugar Mountain, of people who are no longer children:

If you see him in the subway, he'll be down at the

end of the car,

Watching you move until he knows who you are,

When you get off at your station alone, he'll

know that you are.

Know when you see him