One day a friend posts a video on Facebook, with Elizabeth Cotten singing "Freight Train" (with Pete Seeger). The next day I see a question on What's Rattlin' asking what song Robert Wyatt and Gilad Atzmon credit as "trad" on "I wonder how your breath can last" (only on the vinyl edition of "Shleep" (Domino 2008)). And of course I think it has to be "Freight Train" (and my wife agrees!). Cotten actually wrote this song.
Wyatt sings this (my guess): "Coltrane, Coltrane play so fast. Wonder how your breath can last? I don't know what mode you're in, They all sound great to me".