Thanks Richard. There were 10 in January 1954 still in TOFC service and by November 1954 (shared by you) they were all listed as FM’s again.
In May 1950 there were over 40 converted (I stopped counting)
Therefore, for my August 1957 layout my Intermountain model of 17317 will be fine as a flat car.
Brian J. Carlson, P.E.