Under this plan it is evident that every community would pay its equitable share of the cost of transportation, since the rates would be based on the cost of service.[6] Instead of roads running along, bankrupt for years, as now, we would have every community paying for its transportation facilities just what it cost to furnish them. But if, on any road, such a rule would raise the rates above a certain prescribed maximum point, then the rate could be lowered, if necessary, to a point where it was only great enough to pay the operating expenses; and part or all the bond interest would be paid out of the government railway fund. [6] It should be explained that it is only proposed to base the _rates as a whole_ upon the cost of service. As regards the relative rates on different commodities, the author, in common with all who have given careful study to the question, recognizes that the only equitable principle for proportioning rates is the much maligned one of "charging [in proportion to] what the traffic will bear." The argument against this principle is so very plausible that, until he had given the subject thorough study he held a diametrically opposite opinion. To make plain to the reader that this is really the only equitable principle, the following illustration may serve: A coal-mine operator and a sewing-machine manufacturer build together a railroad to carry their respective products to a market. They will fix the total rates of freight at such a point as to just pay the cost of service; but it is required to find what relative rates each should be equitably charged on the shipments from his works. Evidently, to have the rates perfectly equitable, they must be in exact proportion to the _benefit_ which each party derives from the use of the road. But this benefit which each derives is _measured_ by the profits which each makes from his business; and this profit, in turn, is the measure of the amount each can afford to pay for the use of the road,--that is to say, "what the traffic will bear." _Q. E. D._