Perhaps you define "graces" differently than I do. They pay to use those rails and are therefore at the mercy of the contract they sign, not the good graces of the owner.
Rail cargo is not generally high-priority stuff, but they do have to pay to have the train underway.
Rail lines do have to be repaired and up north summer is the time for doing it.
Part of that contract specifies that if the passenger train doesn't make its time window, the freight is coming through. Passenger service just has to wait.