This is obviously a deadheading move of an empty Siemens trainset, which doesn’t trigger any of the speed restrictions, as CN has no problem detecting the presence of the leading legacy trainset.
Very obviously, not.
Edit: are you on train 50/60 or 52/62? In which case, this would indeed be a practical way of getting around the issue. Even more so, if both trains were Siemens trainsets (though the Montreal-bound trainset would be subject to the restrictions once the trains have split in Brockville). However, it only applies to these two departures per day, so a tiny fraction of departures which need to be covered by Siemens trainsets on any given day...