Well volks, for better or worse, it certainly looks as if the KCS-CP combination will soon be a done deal.
Noted earlier in the topic is the "reshoring" of manufactured goods. The manufacturing "base South of the Border" appears to be centered around Monterrey, NL. which is exclusively served by KCSM, or soon-to-be KCS-CP. I continue to hold, even if the "crisis" confronting ocean shipping from inadequate maritime port berths has abated, if security issues can be addressed, the Port of Lazaro Cardenas, Mich could become a "world class" facility. It's a very safe assumption that the costs to handle a vessel there, are considerably less than at, say, LA or Savannah, and, again, KCSM "owns it".
Now what "countermeasures" will our "two Uncles" attempt? "Pete" already serves Mexico with his substantial ownership interest in the Ferromex lines, which are largely comprised of the one time Southern Pacific-Mexico system, and through Mexicali, can interchange to his UP system.
But what will "Warren" do? He appears now to be shut out of X-border traffic. Yes, he has very tenuous trackage rights into Laredo over MP/UP (the "Mop-up"

) and does make rates with KCSM there, but will he be even more disadvantaged than he presently is?
I would not put it past Uncle Warren to seek trackage rights (his own trains) into the Monterrey industrial area.
All told for me, personally, is to note that the "hulk of a railroad" to which claimed eleven years of my life, will now become a player in providing transportation through the Midwest (100 car Container trains through Stillman Valley, Davis Jct, and Kirkland? who would ever dream that). So far as the Chicago area communities that claim to be adversely affected by the prospect of increased freight traffic, "sorry 'bout that". The railroads were there first; the communities built up lineside.
All told, this KCS-CP combination will benefit the railroad industry.
disclaimer: author held position KSU; sold out much too early.