When a Southern California girl such as Gillian Welch gets onstage in a house dress and channels a Depression-era Iowan, it proves the spirit of traditional bluegrass won't be tempered. It also proves you don't need anything more than a guitar to have soul. With the seductiveness of snake charmers, the Freight Hoppers spin out dance tunes on guitar, banjo, fiddle and bass. A quartet influenced by the Stanley Brothers and Uncle Dave Macon, the Freight Hoppers take "Mississippi Breakdown" and "Sandy River" as mountain music purists, and the grieving lament "Little Sadie" never sounded better. As the liner notes say, it's the golden age of country that the Freight Hoppers recapture, the era in the 1920s-30s when mountain musicians hybridized their styles with popular music, jazz and classical. No question about it, the spirit of old-timey music from when Maybelle Carter was knee-high to a june bug lives on in the younger generation (younger for now, anyway). But while purism has its place, it begs the question: What about inventiveness? Maybe the Freight Hoppers will one day come down from the mountains for a look at modern music.