The only Soo Line caboose that I have been privileged to ride in is this one, #31, which is beautifully preserved at the Minnesota Transportation Museum in St. Paul. On the day of my visit, August 1, 2009, the MTM was giving rides to museum guests in caboose 31. Sorry, I don't recall what locomotive was in use that day, but I am pretty sure it wasn't a Soo engine. As for whether or not this caboose was ever used for the famous "mixed trains" in Wisconsin and Michigan, which lasted into the mid-1980s, is anyone's guess.