This Tetsudou Fan news item mentions the 川越貨物線, the Kawagoe Freight Line. A search on this turns up nothing. Is this an error? I don't see any obviously separate tracks on aerial maps, either. Infrequently used connector/bypass lines are a major interest of mine, what's this all about? :)
http://railf.jp/news/2015/02/28/170000.html