One reason early 1970s Vertigo releases hold up so well is they were progressive but not explicitly arty. This Gravy Train album is a fantastic example. Basically this is blues derived rock. But as many of the best progressive bands, Gravy Train did not try to reinvent the wheel, or make the wheel a symphony. A fresh turnaround here, an expansion of a bridge there, and the form was new with only subtle modifications.
With the flute giving this music a sharp and welcome twist and roots deep in both jazz and blues, Gravy Train has not dated a bit.