Hard to tell, I was under the impression that the WC was formed to take over all the abandoned C&NW and SOO secondary lines sometime after the 70s, but someone else told me they existed long after that. Here's a pic of the other side of 2713 in Stevens Point;
SOO on the tender, Wisconsin Central on the cab. I moved to Stevens Point in 2005, and I have seen several WC switchers and even an Illinois Central loco from who knows where mixed in with all the CN stuff in that yard. Who owned what when is still a mystery to me.
WCL...
That brings back some fond memories for sure.
I can still remember being young, pacing two IC SD40-2's and a WC SD45 down US 45 from Arcola to Mattoon, Illinois. The sound of two 16 cylinder 645's and a 20 cylinder 645 throbbing at full bore accelerating from a 40mph zone to a 55 with nearly 10,000 feet of train behind. Nathan P5 airhorn blaring on the lead IC unit...
Can't find that stuff on YouTube hardly, but the memories will never leave me.