I don't know about that slime green color. As you said, it didn't go with anything else, It may have been a color that Grand Detour, EB or Osborne used.
Here is a tidbit from our dealer arcives. the Herkimer rail yard is the one that did not have a freight depot, just a siding, so unloading rail cars was a chalange. A lot of our NI equipment came in there also.