There is a long discussion of "The Wreck of the Old 97" and its antecedents in Norm Cohen's book, the Long Steel Rail.
The Metrorail Song, a shortened version of "Charlie on the MTA" (The MTA Song) is in the DT, but the full song is not in the DT or the Forum. The Kingston Trio changed some words and left out a verse.
"Charlie On the MTA" is © by Jacqueline Steiner and Bess Lomax-Hawes. Only 2 copies of the original recording are known to exist. Find another and you can buy a world cruise at the least.
The full song and story are on the Mass. Inst. Tech. site: http://web.mit.edu/jdreed/www/t/charlie.html