Norm Cohen, Long Steel Trail: The Railroad in American Folksong (University of Illinois Press, 1981, pp. 491-502, under "The Longest Trail/In the Pines") gives quite a comprehensive discography, with title variants. Other indexes on the web include Folk Music Index ("in the pines" etc.), and The Traditional Ballad Index (only a handful). CD search such as glacenote may be helpful (Click here for the results).

~Masato