CN has a busy yard in Neenah astride the main line between Superior, WI and Chicago, IL.
It can be reached by exiting off of I-41 and following the tracks north into Neenah.
The former Wisconsin Central mainline that splits off to the north from Neenah to Appleton, Kaukauna, Green Bay, and Marinette heads into the Upper Peninsula.
Near and at Escanaba it splits with lines to Phillips, WI, Iron Mountain, MI, Baraga, MI, and Sault Ste. Marie, MI.
The lines to Phillips and Sault Ste. Marie are remnants of the original Minneapolis, St. Paul & Sault Ste Marie mainline from Minneapolis to Sault Ste. Marie, which was the original Soo Line.
Purportedly the original Soo Line was conceived as the original Chicago Bypass for traffic from Minneapolis to Detroit, Southern Ontario, and the large population centers of the Northeast.)
https://cnebusiness.geomapguide.ca/
The Watco-owned Fox Valley & Lake Superior (FOXY) operates one line from Appleton to New London and Manawa, and one line from Appleton to Shawano.
At Green Bay, FOXY operates a line from Green Bay to Denmark and a line from Green Bay to Luxemburg.
https://www.watco.com/system-map/
GP38-2 models are the locomotive of choice for FOXY.
https://www.railpictures.net/photo/794232/