Let me think... I believe in order to exceed 79mph one would have to cut out the over speed switch. No reason to tinker with the cab signal or other PTC systems as they would not be active. Once back, the over speed would have to be cut back in and sealed.
Toronto-Windsor currently has 4 trains per day, with running time of about 4h to 4h30
https://www.viarail.ca/sites/all/files/ ... etable.pdf