Some favorites:

BILL MASON-Charlie Poole, Jim Watson,
THE MONKEY AND THE ENGINEER-Jesse Fuller
LONELY DEADHEAD BOXCAR-Al Grierson
THE TRAIN CARRYING JIMMIE RODGERS HOME-Greg Brown, Nashville Bluegrass Band
WAY OUT THERE-Sons Of The Pioneers, Pete Seeger
LININ' TRACK-Library Of Congress field recordings, Leadbelly, Koerner Ray & Glover, Taj Mahal
THE WILD DOGS OF KITWANGA-Al Grierson

And Check out the Library of Congress album Railroad Songs and Ballads (originally AFS L61 on LP-now Rounder CD 1508)