It's true that there are negotiations between CN and CP about using the tracks. But now, urban transit authorities will be forced to get the certificate. If there are discussions on the quality of the tracks, for example, they will have to refer directly to the contract negotiations with the operators, because the operators don't have the same responsibilities. An operator carrying or transporting wood does not have the same responsibilities as an operator transporting people. Their responsibilities are currently bound by a contract. So, if you are ever questioning a certificate because you find there is a problem with the track or whatnot, the parties will be forced to go renegotiate the contract.
What urban transit authorities are afraid of is the cost. They are not necessarily afraid of getting that, but rather of who is going to pick up the bill. Ultimately, they are going to be the ones paying. And you are well aware of that. There is no choice when it comes to transporting people; it must be done every day and if, at some point, work has to get done, some of the risks will be transferred over. You are about to transfer the burden to the transit authorities. That is not your intent, but I am telling you that is what is going to happen...