I know what you’re thinking, ‘cause I thought it myself before the last Ramble in 2008: By anyone’s measure, he’s one of the greatest drummers of the century — but given his well-publicized health troubles, how much steam could the guy really have in him? I know the full weight of these words, so I’m not just slinging them lightly: the show that ensued was likely one of the best ever performed at The Ryman — a night where the host’s indefatigable spirit, the all-star guests’ obvious affection and the music’s swaggering vitality fused into a carnival you never wanted to end, a schooling in American music from the Civil War on. Every song, Helm the timekeeper found a way to rewire your heartbeat. (Every time he spoke between songs, all I could hear was the glorious drawl of his narration from The Right Stuff: “And for a brief mow-ment, Gordo Cooper became the greatest pahlot anyone had ever seen!”) This one features Gillian Welch, the David Rawlings Machine, Rodney Crowell and Sam Bush, and those are just the announced guests. As for the man of honor, well, nobody told him there was any last waltz: he’s still playing like he’s two hours into a square dance and he’s just getting limbered up.