DM&E was making money - Not a lot, but doing quite well based on the track upgrades they did to much of the main line. Remember, they were not a public corporation, and did not have to issue financial statements for public inspection.
As far as I know if you dig @ the STB you can find carloadings and finacials…It may take a while but I know its there.
It might be in the annual “R-1” report to the STB, which contains most (if not all) of that kind of data:
http://www.stb.dot.gov/stb/industry/econ_reports.html
http://www.stb.dot.gov/econdata.nsf/f039526076cc0f8e8525660b006870c9?OpenView
However, it looks like those reports at this link are for Class I’s only, which would not include the DM&E (a Class 2, I believe).
Class 2 in the FRA sense, “Regional” in the AAR sense. (the two are different)