One thing to consider with intermodal traffic, is that Detroit is an easy dray from any of the Chicago terminals, with the added benefit that it's easy to find loads to take back to Chicago. (Indianapolis is in a similar situation)
On the other hand, CSX and CP both move container traffic to/from Detroit via North Baltimore OH, in CSX's instance how much of that arrives/departs North Baltimore via the UP & BNSF trains that originate/terminate there, I do not know.
In the Penn Central era, it made sense not to have any interest in the line west of Kalamazoo and to force it on Amtrak as part of Conrail's creation, considering everything could still be routed through Elkhart yard. As for the Canada Southern, yes it was a victim of Conrail's 1980's era rationalizations. There's a Trains magazine article from the era that details the proposed sale, who else proposed purchasing the line besides CN & CP (Matty Moroun was one of them) and the fear - which proved to be correct, that if CN & CP won, they would keep the border crossings and abandon the rest. (it's also interesting to note that the other two US railroads that ran Detroit-Buffalo via Canada (NS & CSX) at the time, gave up their routings as well)
Long story short, if the trailer/container bound for Detroit leaves the rail car at any of the Chicago terminals - it's most likely going to go to Detroit on the Interstate.
ConrailDetroit wrote: ↑Sat Apr 16, 2022 4:25 pmHow does the NS justify allowing another railroad with trackage rights to lay track between theirs, and being excluded from using?