A few months ago I discussed the absolute signaling disaster the potential purchase of Pam Am by CSX would be. Since rail mergers are suddenly in vogue again, Canadian National and Canadian Pacific are nowboth bidding for Kansas City Southern and I am sure at least someone out there is interested in what this will mean for the signaling on the KCS.
To make a long story short, not much. Not only is KCS pretty much entirely Darth Vader masts or slightly older traffic lights, both CN and CP are good about preserving the unique signal rules of their subsidiaries. For example the CN owned Grand Trunk Western route uses a very NORAC style speed signaling system. That feeds into the CN owned Illinois Central that still uses a bland weak route signaling system, which is also distinct from the CN owned EJ&E's signaling system. So yeah, don't sweat this one, just sit back and enjoy the C40-8s or SD70ACUs.