Wow, there's something I never expected to see on TRW.
I may have that article, I'll have to look.
The first things you want to do is join the MNSHistory and possibly the TwinCityRails yahoo groups. The MNS groups isn't very active on it's own but has a bunch of files to look at including hand sketched maps, and the TCR group has mostly gone to Facebook. But the Twin Cities has one of the most avid railroad fans you'll ever find and I'm fairly certain there's individuals who worked for either the MNS or SOO post merger.
If you haven't seen them, there's videos on youtube of the High Line.
If nothing else, try and get a hold of Greg Smith (he'll probably be on all those groups). I know he can get you in touch with the right people as there are (at least as of a few years ago) still annual get togethers for the MN&S.
I grew up near the MN&S in St. Louis Park and used to railfan with my dad often. I'm more partial to the north end and still have memories of watching them switch cars along Theo, Worth golf course. But my ultimate memory will always be this bridge in St. Louis Park.
This is where the MN&S crossed over the parallel CNW and MILW lines west out of Minneapolis. Lot's of my childhood was spent walking these lines.
Jason