Somewhere in this house, stuffed away in a box, are slides I took of all passenger stations in Soux Falls in 1971. I don't remember if C&NW had one, but if they did, I have its picture.
A little more to the point, you have to remember that these stations were built in the era when competing railroads were not on speaking terms. Maybe thirty years later, they would co-operate (at the city's urging) in building a union station.
This situation was typical for the time. Aberdeen SD had four stations: M&StL; MILW; C&NW, GN. All were still standing when I lived in SD until 1994. The M&StL station was, I think, a dairy. The GN station housed a law office. This station was right downtown, and was unusual in that although it was small, it was a stub-end terminal. The C&NW station was used for MOW by the DM&E (I think it was later donated to an historical society), and the MILW station was used by the BN on the ex-MILW line they were using for coal trains.
Winona, MN had five railroad stations. Also built during the period when railroads were not on speaking terms.
I'll post an update when I find my slides.