State rate regulation

The state may not select either of these departments for arbitrary control. Thus, it would not be contended that the state might require passengers to be carried for nothing, or that it could justify such action by placing upon the shippers of goods the burden of excessive charges in order to supply an adequate return for the carrier's entire service. And, on the same principle, it would also appear to be outside the field of reasonable adjustment that the state should demand the carriage of passengers at a rate so low that it would defray the cost of their transportation, when the entire traffic under the rate was considered, or would provide only a nominal reward in addition to cost.