This depends on the train lines and what trackage rights they have with the others. So it's not a given that one company will haul cargo from the west coast to

This depends on the train lines and what trackage rights they have with the others. So it's not a given that one company will haul cargo from the west coast to the east coast. Interchanges will continue to be important since even within a specific train company the goods may have to be changed to a different train at least once.