You're correct in that they're free to make a commitment. Nobody can force them. If they make a commitment in filing the application for arbitration, the act is very clear that they have to undertake to the railway that they will comply with the commitments they are making for the duration of the arbitrator's decision.
We're trying to get the parties to be bound by a commercial arrangement whereby a shipper commits to do this and an arbitrator, on the basis of the commitments, issues a decision that factors in these commitments, and post arbitrator's decision the relationship between the parties is set forth by the commitments and the arbitrator's decision. So if the shipper does not comply with a commitment and a railway feels harm in any shape or form, the railway can pursue whatever action it wants to pursue, in the same way that a shipper would have the same ability under contract.