https://s3-us-west-2.amazonaws...ne/index.html?page=9
I posted this link earlier in this thread however, it is worth posting again. Read the article, near the end graphite as a rail treatment is discussed. Also in this article is a link to what the black gunk actually is. I would also recommend the reader comments link. There is much info and discussion in Model railroad Hobbyist about cleaning track and wheels. Drop this link in Google:
cleaning wheels site:model-railroad-hobbyist.com
Tom Stoltz
in Maine