Very good question.
The M&StL yahoo website references the IC conection in Albert Lea handling IC reefers with bananas into the Twin Cities. Part of the post lists state of MN blocking further IC access into the state beyond Albert Lea as the IC was a rebel road. (Vern Wigfield post on M&StL yahoo list). Not sure if this would affect things.
The M&StL and the NP also had very close relations. (When the NP Pasco, WA yard was rebuilt about 1955, there was one sort track designated for M&StL, and from Pasco, the nearest direct interchange was St. Paul, MN).
Why the NP paperwork lists the Milwaukee as having a lock, is not entirely clear however in absense of other data, as a researcher, I am rather tied into what I find on paper unless a better source is found.
It is really to bad all our first person sources are thinning out. And I am happy that people like Tony T. and other interviewed those that they did find about reefer traffic. Jim Dick - St. Paul